Fortnight (fn) - Unit Information & Conversion

Quick Answer

1 fortnight = exactly 14 days = 2 weeks

Time equivalents:

• 336 hours
• 20,160 minutes
• 1,209,600 seconds
• 0.5 lunar months (approximately)
• ~0.038 years (1/26 of a year)

Common usage: "I'll see you in a fortnight" = "I'll see you in two weeks"

Geographic distribution: Standard term in UK, Ireland, Australia, New Zealand, and Commonwealth nations; rare in North America.

Quick Comparison Table

Period	Days	Fortnights	Common Use
Week	7	0.5	Standard work/school cycle
Fortnight	14	1	UK/AU pay periods, rent cycles
Month (average)	30.44	2.17	Calendar months
Lunar month	29.53	2.11	Moon cycle
Quarter	91.25	6.52	Business quarters
Year	365.25	26.09	Annual cycle

Definition

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.

History

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.

Real-World Examples

Employment and Payroll

UK/Australia/NZ standard: Most salaried and hourly workers receive wages every fortnight (every other Friday, for example).

Annual salary to fortnight:

• Annual salary: $52,000
• Fortnightly gross pay: $52,000 ÷ 26 = $2,000 per fortnight

Contrast with other systems:

• Weekly pay: 52 pay periods per year
• Fortnightly pay: 26 pay periods per year
• Monthly pay: 12 pay periods per year

Rental Agreements (Australia)

Australian rent: Rental listings in Australia quote rent per fortnight, not per month.

Example:

• Rent: $600 per fortnight
• Monthly equivalent: $600 × 26 ÷ 12 = $1,300 per month

Why fortnightly? Aligns with pay cycles—tenants paid fortnightly can budget one paycheck for rent.

Publishing Schedules

Magazines and journals: Some UK publications release issues every fortnight.

Examples:

• The Spectator: Weekly (but historically had fortnightly periods)
• Private Eye: Fortnightly satirical magazine (UK)
• Academic journals sometimes use fortnightly review cycles

Television and Media

Reality TV: British and Australian reality shows often feature "fortnightly evictions" or challenges.

Example:

• Big Brother UK/Australia: Contestants evicted every fortnight

Sports: Some sports leagues use fortnightly schedules for matches or tournaments.

Government Benefits and Payments

UK benefits:

• Universal Credit: Can be claimed fortnightly
• Some pensions: Paid every two weeks

Australian Centrelink:

• JobSeeker Payment: Fortnightly installments
• Age Pension: Paid fortnightly

Project Planning and Scheduling

Agile development: Some software teams use two-week sprints (essentially fortnights) for iterative development.

Construction: Fortnightly progress meetings for UK/Australian construction projects.

Common Uses

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."

Conversion Guide

Fortnights to Days

Formula: Days = Fortnights × 14

Examples:

• 1 fortnight = 14 days
• 2 fortnights = 28 days
• 0.5 fortnight = 7 days (1 week)

Fortnights to Weeks

Formula: Weeks = Fortnights × 2

Examples:

• 1 fortnight = 2 weeks
• 3 fortnights = 6 weeks
• 6 fortnights = 12 weeks

Fortnights to Hours

Formula: Hours = Fortnights × 336

Examples:

• 1 fortnight = 336 hours
• 0.5 fortnight = 168 hours (1 week)
• 2 fortnights = 672 hours

Fortnights to Months (Approximate)

Formula: Months ≈ Fortnights × 0.4603 (using average month of 30.44 days)

Examples:

• 1 fortnight ≈ 0.46 months
• 2 fortnights ≈ 0.92 months
• 3 fortnights ≈ 1.38 months

Fortnights per Year

Formula: 365.25 days ÷ 14 days = 26.089 fortnights per year

Practical rounding: 26 fortnights per year (for pay periods)

Annual Salary to Fortnight Pay

Formula: Fortnight gross = Annual salary ÷ 26

Examples:

• $52,000/year ÷ 26 = $2,000/fortnight
• $70,000/year ÷ 26 = $2,692.31/fortnight
• $100,000/year ÷ 26 = $3,846.15/fortnight

Common Conversion Mistakes

1. Confusing Bi-Weekly with Fortnightly

The Mistake: Assuming "bi-weekly" always means "every two weeks"

The Problem: "Bi-weekly" has two meanings in English:

• Every two weeks (American usage, equivalent to fortnightly)
• Twice per week (also valid)

The Fix: Use "fortnightly" (Commonwealth English) or "every two weeks" (American English) for clarity. Avoid "bi-weekly" in international contexts.

Example:

• Ambiguous: "Bi-weekly meetings"
• Clear: "Fortnightly meetings" or "Meetings every two weeks"

2. Incorrect Annual Fortnight Count

The Mistake: Assuming 24 or 25 fortnights per year

The Truth: 365.25 days ÷ 14 = 26.089 fortnights per year

Payroll standard: 26 pay periods for fortnightly wages

Impact: Using 24 fortnights creates 4-week gap in annual calculations.

3. Month-to-Fortnight Rent Conversion Errors

The Mistake: Multiplying fortnight rent by 2 to get monthly rent

Why It's Wrong:

• 1 month ≠ 2 fortnights
• Average month = 30.44 days
• 2 fortnights = 28 days

Correct formula: Monthly rent = Fortnight rent × 26 ÷ 12

Example:

• Fortnight rent: $800
• Wrong: $800 × 2 = $1,600/month
• Correct: $800 × 26 ÷ 12 = $1,733.33/month

Difference: $133.33/month (significant!)

4. Mixing American and British Terminology

The Mistake: Using "fortnight" in American business documents

The Problem: Many Americans don't understand "fortnight" and may misinterpret schedules.

The Fix:

• In US contexts: Use "two weeks" or "every two weeks"
• In UK/Commonwealth contexts: "Fortnight" is standard and clear

5. Assuming Fortnight = Half Month

The Mistake: Treating fortnight as exactly half a calendar month

The Truth:

• Fortnight: 14 days (fixed)
• Half month: 14-15.5 days (varies by month)
• February: 14 days = half month (coincidence!)
• January: Half month = 15.5 days (11% longer than fortnight)

Impact: Semi-monthly pay (1st and 15th) ≠ fortnightly pay (every 14 days)