Week to Fortnight Converter
Convert weeks to fortnights with our free online time converter.
Quick Answer
1 Week = 0.5 fortnights
Formula: Week × conversion factor = Fortnight
Use the calculator below for instant, accurate conversions.
Our Accuracy Guarantee
All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.
Week to Fortnight Calculator
How to Use the Week to Fortnight Calculator:
- Enter the value you want to convert in the 'From' field (Week).
- The converted value in Fortnight will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Time category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Week to Fortnight: Step-by-Step Guide
Converting Week to Fortnight involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Week = 0.5 fortnightsExample Calculation:
Convert 60 weeks: 60 × 0.5 = 30 fortnights
Disclaimer: For Reference Only
These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.
Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.
Need to convert to other time units?
View all Time conversions →What is a Week and a Fortnight?
The week (symbol: wk or w) is a unit of time equal to 7 days, 168 hours, or 10,080 minutes.
Official status: The week is not an SI unit, but it is accepted for use with the SI due to its universal cultural importance. The SI base unit of time is the second, and the day is the fundamental accepted non-SI unit.
Standard conversions:
- 1 week = 7 days (exact)
- 1 week = 168 hours (7 × 24)
- 1 week = 10,080 minutes (7 × 24 × 60)
- 1 week = 604,800 seconds (7 × 24 × 60 × 60)
- 1 year ≈ 52.14 weeks (365 ÷ 7)
- 1 month ≈ 4.35 weeks (30 ÷ 7)
The 7-day structure: The week consists of seven consecutive days, typically organized as:
International (Monday-first) convention:
- Monday (Moon's day) - Start of work week
- Tuesday (Tiw's day, Norse god of war)
- Wednesday (Woden's day, Odin)
- Thursday (Thor's day, god of thunder)
- Friday (Frigg's day, goddess of love)
- Saturday (Saturn's day)
- Sunday (Sun's day) - Traditional day of rest
US (Sunday-first) convention:
- Sunday considered first day of the week on US calendars
- Work week runs Monday-Friday
- Weekend is Saturday-Sunday
ISO 8601 standard:
- Monday is officially day 1 of the week
- Sunday is day 7
- Week numbering: Week 1 contains first Thursday of year
Workweek vs. weekend:
- Workweek/weekdays: Monday-Friday (5 days) in Western tradition
- Weekend: Saturday-Sunday (2 days) in Western tradition
- Varies by culture: Friday-Saturday in Muslim countries, Sunday only historically
Why 7 days, not 5, 8, or 10? Unlike the day (Earth rotation) or year (orbital period), the week has no astronomical basis. It's purely a human cultural construct that gained universal adoption through:
- Ancient Babylonian astronomy (7 visible celestial bodies)
- Jewish religious tradition (Genesis creation, Sabbath commandment)
- Christian adoption and spread (Sunday worship)
- Islamic adoption (Friday as holy day)
- Roman Empire standardization (321 CE Constantine decree)
- Deep cultural entrenchment making change impractical
The Fourteen-Day Period
A fortnight is precisely 14 consecutive days, representing two full weeks.
Exact equivalents:
- 14 days (by definition)
- 336 hours (14 days × 24 hours)
- 20,160 minutes (336 hours × 60 minutes)
- 1,209,600 seconds (20,160 minutes × 60 seconds)
Not variable: Unlike months (28-31 days), the fortnight is always exactly 14 days, making it a consistent scheduling unit.
Etymology: Counting by Nights
The word "fortnight" combines:
- "Fourteen" (the number 14)
- "Night" (from Old English "niht")
Old English origin: "Fēowertīene niht" = "fourteen nights"
Why nights, not days? Ancient Germanic peoples observed the lunar cycle for timekeeping. The moon's visibility at night made nights more prominent for tracking time than daylight periods. This night-counting tradition appears in related Germanic languages:
- Dutch: "veertien dagen" (fourteen days) — shifted from nights to days
- German: "vierzehn Tage" (fourteen days) — also shifted to days
- Icelandic: "fj
ógur dagar" (fourteen days)
English uniquely preserves the "night" etymology, though modern usage refers to the complete 14-day period regardless of time of day.
Relationship to Weeks and Months
Two weeks: A fortnight is exactly half a lunar month (~29.5 days ÷ 2 ≈ 14.75 days), though slightly shorter. This makes it a natural intermediate period between the week (7 days) and the month.
Calendar months:
- 26-27 fortnights per year (365.25 days ÷ 14 = 26.09 fortnights)
- ~2.17 fortnights per month (30.44 days ÷ 14)
The fortnight provides a convenient subdivision smaller than a month but larger than a week, useful for payroll, rent, and recurring obligations.
Note: The Week is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Fortnight belongs to the imperial/US customary system.
History of the Week and Fortnight
of the Week
Ancient Babylonian Origins (c. 2000-1000 BCE)
The 7-day week's roots lie in ancient Mesopotamian astronomy and astrology:
Babylonian astronomy:
-
Observed seven "wandering stars" (planets) visible to naked eye:
- Sun (Shamash) - brightest object
- Moon (Sin) - most obviously changing
- Mercury (Nabu) - messenger god
- Venus (Ishtar) - morning/evening star
- Mars (Nergal) - red planet, war god
- Jupiter (Marduk) - king of gods
- Saturn (Ninurta) - slow-moving
-
Each celestial body "ruled" one day
-
Seven was considered mystical/sacred number
-
Used in astrological predictions and religious rituals
Why 7 was special:
- Seven visible "planets" (including Sun and Moon)
- Seven days between moon phases (~7.4 days per quarter)
- Mathematical: 7 is prime, making it special
- Religious significance in Near Eastern cultures
Note: The moon's phases (29.5 days ÷ 4 ≈ 7.4 days) may have influenced the 7-day cycle, though it doesn't align perfectly.
Jewish Religious Codification (c. 1500-500 BCE)
The Hebrew Bible (Torah) embedded the 7-day week in religious law:
Genesis creation narrative (Genesis 1:1-2:3):
- Day 1: Light and darkness
- Day 2: Sky and waters
- Day 3: Land, seas, plants
- Day 4: Sun, moon, stars
- Day 5: Fish and birds
- Day 6: Land animals and humans
- Day 7: God rested → Sabbath (Shabbat)
Fourth Commandment (Exodus 20:8-11):
"Remember the Sabbath day, to keep it holy. Six days you shall labor and do all your work, but the seventh day is a Sabbath to the Lord your God."
Sabbath observance:
- Saturday (7th day) as mandatory day of rest
- No work permitted (cooking, travel, commerce)
- Synagogue worship and family meals
- Violations carried severe penalties (death in ancient times)
- Core to Jewish identity for 3,000+ years
Jewish week structure:
- Days numbered: Yom Rishon (Day 1) through Yom Shishi (Day 6)
- Only Shabbat (Sabbath, Day 7) has a name
- Week begins Saturday evening (sunset) and ends following Saturday sunset
Greek and Roman Adoption (300 BCE - 400 CE)
Greek influence:
- Hellenistic astronomers (post-Alexander) adopted Babylonian astrology
- Each day associated with a planet/deity
- Week spread through Greek-speaking world
- Ptolemy's astrology (2nd century CE) codified planetary hours and days
Roman nundinal cycle (753 BCE - 321 CE):
- Romans initially used 8-day market week (nundinae)
- Days labeled A through H
- Markets held every 8th day
- Used for agricultural and commercial scheduling
Planetary week adoption (1st-3rd century CE):
- 7-day planetary week entered Rome from Near East
- Coexisted with 8-day nundinal cycle
- Gradually replaced nundinal week for religious/astrological reasons
- Days named after planets/gods:
- Dies Solis (Sun) → Sunday
- Dies Lunae (Moon) → Monday
- Dies Martis (Mars) → Tuesday (Tiw = Germanic Mars)
- Dies Mercurii (Mercury) → Wednesday (Woden = Germanic Mercury)
- Dies Jovis (Jupiter) → Thursday (Thor = Germanic Jupiter)
- Dies Veneris (Venus) → Friday (Frigg = Germanic Venus)
- Dies Saturni (Saturn) → Saturday
Constantine's decree (321 CE):
- Emperor Constantine I officially recognized the 7-day week
- Declared Sunday (Dies Solis) a day of rest
- Aligned with Christian practice (resurrection day)
- Marked official end of nundinal cycle
- Made 7-day week legal standard across Roman Empire
Christian Transformation (1st-5th century CE)
Early Christian practice:
- Jewish Christians initially observed Saturday Sabbath
- Gradually shifted to Sunday (Dies Dominica, "Lord's Day")
- Commemorated Jesus's resurrection (Sunday morning)
- Sunday worship established by 100 CE
Christian week structure:
- Sunday: Lord's Day, primary worship
- Monday-Saturday: Workdays
- No Sabbath work prohibition (unlike Judaism)
- Sunday rest became custom, not religious law initially
Church influence:
- Constantine's decree (321 CE) made Sunday official rest day
- Christian terminology replaced pagan planet names in some languages:
- Portuguese: Domingo (Sunday = Lord's Day), Segunda-feira (Monday = Second day)
- Some Slavic languages: similar pattern
- Christian calendar organized around Sunday as "first day of week" (Western tradition)
Medieval Christian week:
- Elaborate liturgical calendar
- Different saints' days on specific weekdays
- Friday fasting (commemorating crucifixion)
- Sunday mandatory Mass attendance
- Week structured around religious observances
Islamic Adoption (7th century CE)
Islamic week (al-usbūʿ):
- Adopted existing 7-day week structure
- Friday (Jumu'ah) designated as day of congregational prayer
- Not a "day of rest" like Sabbath/Sunday—work permitted
- Friday midday prayer (Jumu'ah prayer) mandatory for men
Islamic day names:
- Days numbered similar to Hebrew tradition
- Saturday: Yawm as-Sabt (Day of the Sabbath—Hebrew influence)
- Sunday: Yawm al-Ahad (First day)
- Monday: Yawm al-Ithnayn (Second day)
- ...
- Friday: Yawm al-Jumu'ah (Day of Congregation)
Spread of Islamic week:
- Islamic expansion (7th-15th centuries) spread 7-day week to:
- North Africa
- Middle East
- Central Asia
- Parts of Southeast Asia
- Reinforced 7-day week as global standard
Global Standardization (1500-1900)
European colonialism:
- Spanish, Portuguese, French, British empires spread 7-day week
- Christian Sunday observance imposed in colonies
- Replaced indigenous time-keeping systems:
- Aztec 13-day and 20-day cycles
- Mayan complex calendar system
- Various Asian lunar-based systems
East Asia adoption:
- China: Adopted 7-day week in early 20th century (previously used 10-day xún divisions)
- Japan: Officially adopted 7-day week in 1873 during Meiji Restoration
- Korea: Adopted with modernization in late 19th/early 20th century
International commerce:
- Global trade required synchronized schedules
- Shipping and maritime schedules used 7-day week
- Telegraph and later telecommunications standardized weekly communications
Failed Reform Attempts
Despite universal adoption, several attempts to "improve" the week failed:
1. French Revolutionary Calendar (1793-1805):
- Replaced 7-day week with 10-day décade
- Aligned with metric system (10 days per week, 3 weeks per month)
- Days numbered Primidi through Décadi
- Only Décadi was rest day (1 in 10 vs. 1 in 7)
- Failed because:
- Less frequent rest days unpopular with workers
- Conflicted with Christian Sunday observance
- Disrupted social and family patterns
- Napoleon abolished it in 1805
2. Soviet 5-day and 6-day weeks (1929-1940):
-
1929-1931: 5-day "continuous week"
- Days numbered 1-5
- Each worker got one of five days off (rotating)
- Goal: Continuous factory production
- Problem: Families/friends couldn't synchronize time off
-
1931-1940: 6-day week
- Days numbered 1-6
- Day 6 was universal rest day
- Goal: Improve on 5-day system
- Problem: Still disrupted religious observance, traditional patterns
-
1940: Return to 7-day week
- Abandoned experiments
- Restored traditional Sunday rest
- 7-day week too culturally embedded to change
3. International Fixed Calendar (1923-present, never adopted):
- Proposed by Moses B. Cotsworth
- 13 months of 28 days each (4 perfect weeks per month)
- Extra month called "Sol" between June and July
- One "Year Day" outside the weekly cycle
- Never adopted because:
- Would disrupt all existing calendars
- Breaking the continuous 7-day cycle unacceptable religiously
- Massive economic costs
- Resistance from established institutions
4. Other proposals:
- Decimal weeks (10 days)
- 5-day weeks (aligned with work week)
- 8-day weeks (better divides into month)
- All failed: Cultural inertia too strong
Modern Universal Adoption
Current status:
- All 195+ countries use the 7-day week
- Synchronized globally despite cultural differences
- ISO 8601 standard (Monday = day 1, week 1 contains first Thursday)
- Different weekend patterns:
- Saturday-Sunday: Most of world (Christian tradition)
- Friday-Saturday: Many Muslim countries (Saudi Arabia, UAE until 2022)
- Friday only: Iran
- Sunday only: Historical in some countries
Why 7-day week succeeded:
- Religious universality: Judaism, Christianity, Islam all use 7-day week
- Ancient origins: 3,000+ years of continuity
- Global colonization: European powers spread it worldwide
- Economic integration: International commerce requires synchronization
- Cultural entrenchment: Too deeply embedded to change
- Mathematical convenience: Fits reasonably with months (4-5 weeks)
- Work-rest balance: 5-2 or 6-1 work-rest ratio culturally accepted
Modern cultural significance:
- Phrase "work week" universal
- "Weekend" concept global (even if different days)
- Weekly planning horizon standard
- Pay periods often weekly or bi-weekly
- Television programming on weekly schedules
- Religious observances every 7 days
- Social rhythms organized weekly
Ancient Germanic Night-Counting (Pre-9th Century)
Lunar observation: Before written calendars, Germanic tribes tracked time using the moon's phases. The new moon to full moon cycle (approximately 14-15 days) created natural fortnight-length periods.
Night prominence:
- Full moons illuminated nights, making them memorable markers
- Daylight periods blurred together without distinct markers
- Nights were counted: "three nights hence," "fourteen nights from now"
This system influenced Old Norse, Old English, and other Germanic languages.
Old English Documentation (9th-11th Centuries)
Anglo-Saxon Chronicle (circa 890 CE): The earliest written English historical record uses "fēowertīene niht" to describe fourteen-day periods in battle accounts and political events.
Beowulf (8th-11th century): The epic poem references time periods measured in nights, including fortnight-length durations for journeys and feasts.
Legal codes: Anglo-Saxon law codes (Aethelberht, Alfred the Great) used fortnights for legal waiting periods and court summons.
Middle English Evolution (12th-15th Centuries)
Spelling variations:
- "Fourtenyght" (14th century)
- "Fourtenight" (15th century)
- "Fourteenyght"
- Gradual simplification toward "fortnight"
Chaucer's Canterbury Tales (1387-1400): Geoffrey Chaucer used fortnight references, solidifying the term in literary English: "And eek me thynketh in my remembraunce, / I have herd telle of a fortnyght or thre"
Medieval commerce: Markets and fairs often operated on fortnight cycles, with merchants returning to towns every two weeks.
Early Modern English (16th-17th Centuries)
Standardization: By the 1500s, "fortnight" became the dominant spelling and pronunciation.
Shakespeare's usage (1590s-1610s): William Shakespeare used "fortnight" frequently across his plays:
- The Tempest (1611): "I'll deliver all; And promise you calm seas, auspicious gales, And sail so expeditious that shall catch Your royal fleet far off. My Araby, chick! That is thy charge: then to the elements Be free, and fare thou well! Please you, draw near." (References to travel time in fortnights)
- The Two Gentlemen of Verona
- Much Ado About Nothing
Shakespeare's widespread influence ensured "fortnight" became standard educated English.
British Empire and Commonwealth Spread (17th-19th Centuries)
Colonial administration: British colonial governments used fortnightly reporting cycles, payment schedules, and administrative periods.
Spread to:
- Australia (colonized 1788 onward)
- New Zealand (colonized 1840 onward)
- India (British Raj, 18th-20th centuries)
- Canada (though later influenced by American "two weeks")
- South Africa, Caribbean, East Africa
Embedded in law: Colonial legal codes, rental agreements, and labor contracts specified fortnightly terms, creating lasting institutional usage.
Industrial Revolution and Labor Movements (19th Century)
Fortnightly wages: British factories and mills established fortnightly pay cycles during the Industrial Revolution (1760-1840):
- Workers received wages every two weeks
- Easier for employers to manage than weekly payroll
- Allowed workers to budget for monthly rent
Labor union influence: Trade unions negotiated fortnightly pay as standard, spreading throughout the British Empire.
Australian adoption: Australian colonies (becoming a federation in 1901) adopted fortnightly wages widely. Today, Australia has the world's highest fortnight usage, with most wages, rent, and bills calculated fortnightly.
American Divergence (20th Century)
"Two weeks" replaces "fortnight": American English gradually abandoned "fortnight" during the 20th century in favor of "two weeks."
Reasons:
- Simplicity: "Two weeks" is more transparent to non-native speakers
- Bi-weekly confusion: "Bi-weekly" can mean either twice per week or once every two weeks, causing ambiguity
- Cultural shift: American preference for straightforward terminology
Result: By the 21st century, "fortnight" sounds archaic or quaint to most Americans.
Modern Commonwealth Usage (1900s-Present)
United Kingdom: Fortnightly payroll, magazine publications ("published fortnightly"), TV schedules (reality shows with "fortnightly evictions").
Australia and New Zealand:
- Dominant time unit: Wages almost universally paid fortnightly
- Rental agreements: Rent calculated per fortnight (not per week or month)
- Government benefits: Welfare payments issued fortnightly
Cultural persistence: Despite global influence of American English, fortnight remains deeply embedded in Commonwealth life, appearing daily in conversation, media, and official documents.
Common Uses and Applications: weeks vs fortnights
Explore the typical applications for both Week (imperial/US) and Fortnight (imperial/US) to understand their common contexts.
Common Uses for weeks
When to Use fortnights
1. British and Commonwealth Payroll
Fortnightly pay period: The most widespread use of fortnight is in employment contracts specifying pay every 14 days.
Advantages:
- 26 pay periods per year (simpler arithmetic than 52 weekly periods)
- Budget-friendly: Easier to align with monthly bills
- Payroll efficiency: Reduces administrative burden compared to weekly pay
Typical schedule: Employees paid on alternating Fridays, creating a predictable two-week cycle.
2. Australian Rental Agreements
Rent calculation: Australian rental market uniquely quotes rent per fortnight rather than per week or per month.
Conversion formulas:
- Fortnight to month: Fortnight rent × 26 ÷ 12
- Month to fortnight: Month rent × 12 ÷ 26
Example:
- $700/fortnight = $700 × 26 ÷ 12 = $1,516.67/month
3. Scheduling and Planning
Recurring events: "The committee meets fortnightly" = every two weeks
Vacation planning: "I'm taking a fortnight off" = two-week vacation
Project timelines: "Deliver progress reports every fortnight"
4. Literary and Formal Writing
British literature: Historical novels and formal writing use "fortnight" for period flavor.
Legal documents: UK contracts may specify "a fortnight's notice" for resignations or terminations.
5. Sports and Competition Schedules
Tournament cycles: Some sports competitions use fortnightly rounds.
Training schedules: Athletes may follow fortnight-based training cycles (two weeks of intensive training followed by recovery).
6. Historical and Cultural Context
Period dramas: Films and TV set in Britain use "fortnight" for authenticity.
Example dialogue: "The Duke will return in a fortnight."
Additional Unit Information
About Week (wk)
How many days are in a week?
Exactly 7 days in every week, universally across all cultures and countries worldwide.
This has been standard for over 2,000 years, originating from:
- Ancient Babylonian astronomy (7 visible celestial bodies)
- Jewish religious tradition (Genesis 7-day creation + Sabbath)
- Roman adoption and global spread
The 7-day week has no astronomical basis (unlike day or year) but achieved universal cultural adoption.
How many hours are in a week?
Exactly 168 hours in one week.
Calculation: 7 days × 24 hours/day = 168 hours
Context:
- Work week: 40 hours (standard full-time) out of 168 total
- Sleep: 56 hours per week (8 hours/night × 7 nights)
- Leisure: 168 - 40 (work) - 56 (sleep) = 72 hours
- Work-life balance: Only ~24% of week spent working (40/168)
Why does a week have 7 days?
The 7-day week has cultural and religious origins, not astronomical:
Three main reasons:
-
Babylonian astronomy (c. 2000 BCE):
- Seven visible "planets": Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn
- Each day dedicated to one celestial body
- Seven considered sacred number
-
Jewish religious tradition (c. 1500 BCE):
- Genesis: God created world in 6 days, rested on 7th (Sabbath)
- Fourth Commandment: "Remember the Sabbath day"
- Embedded in religious law for 3,000+ years
-
Global adoption:
- Christianity spread Sunday worship (resurrection day)
- Islam adopted 7-day week with Friday prayers
- Roman Empire standardized it (321 CE Constantine decree)
- Colonial expansion made it universal
Why not 5, 8, or 10 days? All attempts to change it failed (French 10-day, Soviet 5/6-day weeks) due to deep cultural and religious entrenchment.
How many weeks are in a year?
52.14 weeks in a standard 365-day year.
Calculation: 365 days ÷ 7 days/week = 52.14 weeks (52 weeks + 1 day)
More precisely:
- Common year (365 days): 52 weeks + 1 day
- Leap year (366 days): 52 weeks + 2 days
Practical implications:
- 52 "full weeks" per year
- Extra 1-2 days cause annual calendar drift
- Same date falls on different day of week each year
ISO week-numbering:
- Most years: Weeks 1-52
- Some years: Weeks 1-53 (when year has 53 Thursdays)
What is a work week?
A work week is the 5-day period from Monday-Friday when most businesses operate, totaling 40 hours (8 hours/day × 5 days) in the US standard.
Work week structure:
- Weekdays: Monday-Friday (5 days) - work/school days
- Weekend: Saturday-Sunday (2 days) - rest days
- 5-2 split: 5 days work, 2 days rest
Hours:
- US full-time: 40 hours per week standard
- France: 35 hours per week legal standard
- Part-time: 20-30 hours per week
- Overwork: 50-60+ hours per week
Variations:
- 4-day work week: Emerging trend (32-40 hours over 4 days)
- 6-day work week: Historical standard, still common in some countries
- Muslim countries: Friday-Saturday weekend (work Sunday-Thursday)
Origins:
- Industrial Revolution: Standardized factory schedules
- Labor movements: Won 5-day, 40-hour week (1926-1940 in US)
- Henry Ford: Pioneered 5-day, 40-hour week (1926)
- Fair Labor Standards Act (1938): Codified 40-hour week in US
What is the weekend?
The weekend is the 2-day period of rest at the end of the work week, typically Saturday and Sunday in Western countries.
Weekend structure:
- Saturday: First day off
- Sunday: Second day off, traditional Christian day of worship
- Purpose: Rest, recreation, family time, errands
Global variations:
- Western countries: Saturday-Sunday (majority of world)
- Muslim countries: Friday-Saturday or Friday-Sunday (historically)
- Saudi Arabia, UAE: Switched to Saturday-Sunday in 2022
- Iran: Friday only
- Israel: Friday-Saturday (aligns with Jewish Sabbath)
- Brunei, Bangladesh: Friday-Saturday
Origins:
- Jewish Sabbath: Saturday rest day (biblical commandment)
- Christian Sunday: Lord's Day (resurrection observance)
- Industrial era: Originally only Sunday off
- 1920s-1940s: Saturday added, creating "weekend"
- Labor advocacy: "Saturday half-day" became full day off
Cultural significance:
- "Thank God It's Friday" (TGIF)
- "Weekend warrior" (active on weekends)
- "Monday blues" (dreading return to work)
- Weekend social events, sports, entertainment
How many weeks are in a month?
Approximately 4.35 weeks in an average month.
Calculation:
- Average month = 30.44 days (365 ÷ 12)
- 30.44 days ÷ 7 days/week = 4.35 weeks
Actual variation:
- February: 4.0 weeks (28 days), 4.14 weeks (29 days, leap year)
- 30-day months: 4.29 weeks (April, June, September, November)
- 31-day months: 4.43 weeks (January, March, May, July, August, October, December)
Why not exactly 4 weeks?
- 4 weeks = 28 days
- Most months = 30-31 days
- 2-3 days "extra" per month
Implications:
- "Monthly" ≠ "every 4 weeks"
- Monthly salary ≠ 4 weekly salaries
- Rent is monthly (12 times/year), not 4-weekly (13 times/year)
What is a fortnight?
A fortnight is a period of 14 days or 2 weeks.
Origin:
- Old English: fēowertīene niht = "fourteen nights"
- Common in British English
- Less common in American English
Usage:
- UK: "I'll see you in a fortnight" (2 weeks from now)
- Australia/New Zealand: Common term
- Pay periods: "Fortnightly pay" = paid every 2 weeks
- Planning: "Fortnight holiday" = 2-week vacation
Related terms:
- Bi-weekly: Every 2 weeks (26 times per year)
- Semi-monthly: Twice per month (24 times per year)
- Fortnight = bi-weekly interval, not semi-monthly
Why do weekends exist?
Weekends exist due to religious tradition and labor reform:
Religious origins:
- Jewish Sabbath: Saturday rest day (biblical commandment, ~3,000 years old)
- Christian Sunday: Lord's Day, resurrection observance (2,000 years old)
- Both religions mandate one day of rest per week
Industrial era (1800s-1900s):
- Initially: 6-day work week, only Sunday off (Christian influence)
- Workers labored Monday-Saturday, 10-16 hours per day
- Exhausting, no family time
Labor reform (1900s):
- 1908: First 5-day work week proposed
- 1926: Henry Ford adopted 5-day, 40-hour week (factory efficiency + consumer spending)
- 1929: Great Depression led to work-sharing (reduce hours to employ more)
- 1938: Fair Labor Standards Act (US) established 40-hour week with overtime
- 1940: 5-day work week became US standard
Why 2-day weekend prevailed:
- Productivity: Workers more productive with adequate rest
- Consumer economy: Workers with free time spend money
- Family time: Social benefits
- Religious observance: Accommodates both Saturday (Jewish) and Sunday (Christian)
- Union advocacy: Labor movements fought for it
Modern trends:
- 4-day work week experiments (same hours, compressed)
- Flexible schedules: "Weekend" varies by individual
- Remote work blurs work-weekend boundaries
Can weeks start on different days?
Yes, weeks can start on either Sunday or Monday depending on cultural convention, though the 7-day cycle remains constant.
Two main systems:
1. Sunday-first (traditional Christian):
- Used in: United States, Canada, parts of Latin America
- Rationale: Sunday is the Lord's Day, "first day of week" in Christian tradition
- Calendars: US calendars show Sunday as leftmost column
- Biblical: Genesis creation starts with Sunday
2. Monday-first (ISO standard):
- Used in: Europe, Asia, Africa, Australia (most of world)
- ISO 8601 standard: Monday = day 1, Sunday = day 7
- Rationale: Work week starts Monday, weekend (Saturday-Sunday) grouped together
- Calendars: International calendars show Monday as leftmost column
Which is "correct"?
- Both are valid cultural conventions
- ISO 8601 standardizes Monday-first for international business/computing
- Work week universally Monday-Friday regardless
Computing:
- Programming: ISO 8601 standard (Monday = 1)
- Excel/Google Sheets: Can be configured either way
- Date/time libraries: Often use ISO standard
Practical impact:
- Minimal—everyone uses same 7-day cycle
- Only affects calendar layout and "first day" reference
- "Weekend" always means Saturday-Sunday (or local equivalent)
About Fortnight (fn)
How many days are in a fortnight?
Exactly 14 days.
A fortnight is always 14 consecutive days, equivalent to two full weeks (7 days × 2).
Time equivalents:
- 336 hours
- 20,160 minutes
- 1,209,600 seconds
How many weeks make a fortnight?
Exactly 2 weeks = 1 fortnight.
This is the definition of the term: "fortnight" literally means "fourteen nights" (two weeks).
Where does the word "fortnight" come from?
From Old English "fēowertīene niht" (fourteen nights).
Etymology:
- "Fēowertīene" = fourteen
- "Niht" = night
Historical context: Ancient Germanic peoples counted time by nights rather than days, observing lunar cycles. The fortnight represents approximately half a lunar month (~29.5 days ÷ 2).
Evolution: Old English "fēowertīene niht" → Middle English "fourtenyght" → Modern English "fortnight"
Is "fortnight" commonly used everywhere?
No—usage is heavily geographic.
Common in:
- United Kingdom (standard term)
- Ireland (standard term)
- Australia (most common time unit for pay/rent)
- New Zealand (standard term)
- Other Commonwealth nations (varying frequency)
Rare in:
- United States (sounds archaic; "two weeks" preferred)
- Canada (mixed usage; more American influence)
Result: "Fortnight" is standard British/Commonwealth English but virtually unused in American English.
What's the difference between fortnight and bi-weekly?
Fortnight = unambiguous 14-day period
Bi-weekly = ambiguous; two possible meanings:
- Every two weeks (synonymous with fortnightly)
- Twice per week
Recommendation: Use "fortnight" or "every two weeks" to avoid confusion. "Bi-weekly" can mislead readers.
Example:
- Ambiguous: "Bi-weekly payroll" (twice per week or every two weeks?)
- Clear: "Fortnightly payroll" (unambiguous: every 14 days)
How many fortnights are in a year?
Approximately 26.09 fortnights per year.
Calculation: 365.25 days (average year with leap years) ÷ 14 days = 26.089 fortnights
Payroll standard: Employers use 26 pay periods for fortnightly wages, slightly underestimating the true annual length (creates an extra day or two per year).
How do I convert monthly rent to fortnightly rent?
Formula: Fortnight rent = Monthly rent × 12 ÷ 26
Example:
- Monthly rent: $1,500
- $1,500 × 12 ÷ 26 = $692.31 per fortnight
Reverse (fortnight to month): Monthly rent = Fortnight rent × 26 ÷ 12
Example:
- Fortnight rent: $700
- $700 × 26 ÷ 12 = $1,516.67 per month
Is a fortnight half a month?
Approximately, but not exactly.
Fortnight: 14 days (fixed)
Half month: Varies by month
- February: 14 days (coincidentally equal!)
- January, March, May, July, August, October, December: 15.5 days
- April, June, September, November: 15 days
Average half month: 30.44 ÷ 2 = 15.22 days (8.7% longer than fortnight)
Conclusion: Fortnight ≈ half month, but they're distinct concepts.
Why do Australians use fortnights so much?
Historical and practical reasons:
1. British colonial influence: Australia inherited British administrative and commercial systems, including fortnightly wage cycles.
2. Payroll alignment: Fortnightly wages became standard, so rent, bills, and budgeting adapted to match pay cycles.
3. Mathematical convenience: 26 fortnights per year simplifies annual calculations compared to 52 weeks.
4. Cultural entrenchment: Generations of Australians have grown up with fortnightly systems, making it the natural default.
Result: Australia likely uses "fortnight" more frequently than any other nation, including the UK.
Do Americans understand "fortnight"?
Most recognize it, but few use it.
Recognition:
- Americans encounter "fortnight" in British literature, period dramas, and historical contexts
- Educated Americans know it means "two weeks"
Usage:
- Virtually never used in everyday American speech
- Sounds archaic, old-fashioned, or excessively formal
Recommendation: When addressing American audiences, use "two weeks" instead of "fortnight" to ensure clarity.
Conversion Table: Week to Fortnight
| Week (wk) | Fortnight (fn) |
|---|---|
| 0.5 | 0.25 |
| 1 | 0.5 |
| 1.5 | 0.75 |
| 2 | 1 |
| 5 | 2.5 |
| 10 | 5 |
| 25 | 12.5 |
| 50 | 25 |
| 100 | 50 |
| 250 | 125 |
| 500 | 250 |
| 1,000 | 500 |
People Also Ask
How do I convert Week to Fortnight?
To convert Week to Fortnight, enter the value in Week in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our time converter page to convert between other units in this category.
Learn more →What is the conversion factor from Week to Fortnight?
The conversion factor depends on the specific relationship between Week and Fortnight. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.
Can I convert Fortnight back to Week?
Yes! You can easily convert Fortnight back to Week by using the swap button (⇌) in the calculator above, or by visiting our Fortnight to Week converter page. You can also explore other time conversions on our category page.
Learn more →What are common uses for Week and Fortnight?
Week and Fortnight are both standard units used in time measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our time converter for more conversion options.
For more time conversion questions, visit our FAQ page or explore our conversion guides.
Helpful Conversion Guides
Learn more about unit conversion with our comprehensive guides:
All Time Conversions
Other Time Units and Conversions
Explore other time units and their conversion options:
Verified Against Authority Standards
All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.
National Institute of Standards and Technology — Official time standards and definitions
Bureau International des Poids et Mesures — Definition of the SI base unit for time
Last verified: December 3, 2025