Stone to Microgram Converter
Convert stones to micrograms with our free online weight converter.
Quick Answer
1 Stone = 6350293180 micrograms
Formula: Stone × conversion factor = Microgram
Use the calculator below for instant, accurate conversions.
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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.
Stone to Microgram Calculator
How to Use the Stone to Microgram Calculator:
- Enter the value you want to convert in the 'From' field (Stone).
- The converted value in Microgram will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Weight category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Stone to Microgram: Step-by-Step Guide
Converting Stone to Microgram involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Stone = 6350290000 microgramsExample Calculation:
Convert 5 stones: 5 × 6350290000 = 31751500000 micrograms
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 weight units?
View all Weight conversions →What is a Stone and a Microgram?
1 stone = 14 avoirdupois pounds (lb) = 6.35029318 kilograms (kg) EXACT
The stone (symbol: st) is a unit of mass in the Imperial system, legally defined in terms of pounds, which are themselves defined in terms of kilograms. The exact conversion is:
1 pound = 0.45359237 kilograms (international definition, 1959)
1 stone = 14 × 0.45359237 kg = 6.35029318 kg
Stone and Pounds Notation
The stone is almost never used alone for body weight. Instead, it's combined with additional pounds:
Format: "X stone Y pounds" or "X st Y lb"
Examples:
- 10 st 0 lb = 10 stone exactly = 140 lb = 63.5 kg
- 10 st 7 lb = 10 stone + 7 pounds = 147 lb = 66.7 kg
- 12 st 3 lb = 12 stone + 3 pounds = 171 lb = 77.6 kg
Why this format? It provides precision without unwieldy decimal places. Saying "10.5 stone" is rare—people say "10 stone 7" instead (10 stone + 7 pounds = 10.5 stone).
Stone vs. Kilogram vs. Pound
Three systems for measuring body weight:
| System | Unit | Used In | Precision | |-----------|----------|-------------|---------------| | Imperial (UK) | Stone + Pounds | UK, Ireland | "11 st 7 lb" (161 lb) | | Imperial (US) | Pounds only | United States, Canada | "161 lb" | | Metric | Kilograms | Most of the world | "73 kg" |
Cultural difference:
- Americans say "I weigh 161 pounds"
- British say "I weigh 11 stone 7" (rarely "161 pounds")
- Europeans say "I weigh 73 kilograms"
Why 14 Pounds?
The number 14 has no scientific basis—it's purely historical. Medieval England used base-12 counting (duodecimal) for some systems:
- 12 inches = 1 foot
- 12 pence = 1 shilling (pre-1971)
- But 14 pounds = 1 stone (not 12!)
Theory: The 14-pound wool stone emerged from trade practices. A "sack of wool" weighed 364 pounds = 26 stones (26 × 14 = 364), a convenient round number for taxation and commerce.
A microgram (symbol: µg or mcg) is a unit of mass in the metric system equal to one millionth (1/1,000,000) of a gram, or one thousandth (1/1,000) of a milligram.
Key relationships:
- 1 microgram = 0.000001 grams (g)
- 1 microgram = 0.001 milligrams (mg)
- 1,000 micrograms = 1 milligram
- 1,000,000 micrograms = 1 gram
- 1 microgram ≈ 0.0000000353 ounces
Symbol variations:
- µg: Standard scientific symbol (µ = Greek letter mu)
- mcg: Common in medicine/pharmacy (avoids confusion if µ looks like m)
- Both mean exactly the same thing
The prefix "micro-":
- From Greek "mikrós" meaning "small"
- SI prefix denoting 10⁻⁶ (one millionth)
- Also used in: micrometer (µm), microsecond (µs), microliter (µL)
In perspective (how small is it?):
- 1 grain of table salt ≈ 1,000 µg (1 mg)
- 1 speck of dust ≈ 1-10 µg
- Human red blood cell ≈ 100 µg
- A typical dose of Vitamin B12 ≈ 2.4 µg
⚠️ CRITICAL SAFETY WARNING: Never confuse µg (microgram) with mg (milligram). Taking 1 mg when prescribed 1 µg = 1,000x overdose! Always double-check labels and prescriptions.
Note: The Stone is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Microgram belongs to the metric (SI) system.
History of the Stone and Microgram
Ancient and Medieval Origins (Pre-1300)
The concept of standardized stones: Before precise metallic weights, communities used stones as trade counterweights. A merchant would keep a reference stone in the marketplace, verified by local authorities, against which goods were weighed.
Advantages:
- Durability: Stones don't corrode or wear like metal
- Availability: Every village had stones
- Tamper-resistance: Hard to secretly shave weight off a stone
Problem: Every region had different stones! The "stone of wool" in Yorkshire differed from the "stone of wool" in Kent.
Medieval Standardization Attempts (1300-1824)
Edward III's wool stone (1340): King Edward III standardized the wool stone at 14 pounds as part of regulating the lucrative wool trade (England's economic backbone in the Middle Ages). The "sack of wool" was defined as 364 pounds = 26 stones.
Commodity-specific stones: Different goods had different stone weights:
| Commodity | Stone Weight | Reasoning | |--------------|-----------------|---------------| | Wool | 14 lb (6.35 kg) | Trade standard | | Meat | 8 lb (3.63 kg) | Butcher's stone | | Glass | 5 lb (2.27 kg) | Fragile goods | | Cheese | 16 lb (7.26 kg) | Agricultural products | | Iron | Variable (8-15 lb) | Regional differences |
Why different weights? Practical reasons:
- Heavy commodities (iron, lead): Smaller stone weight made counting easier
- Light, valuable goods (wool, spices): Larger stone weight reduced fractions
- Tradition: Each guild jealously guarded its customary weights
The Weights and Measures Act 1824
The problem: By 1800, Britain had dozens of incompatible stone definitions, creating chaos in trade and taxation.
The solution: The 1824 Act standardized British weights and measures:
- 14 pounds = 1 stone (for general use, not tied to specific commodities)
- Stone officially defined in relation to the pound
- Commodity-specific stones discouraged (but not banned)
Imperial standardization: The Act also defined:
- 1 pound = 7,000 grains
- 16 ounces = 1 pound
- 14 pounds = 1 stone
- 8 stone = 1 hundredweight (112 pounds)
- 20 hundredweight = 1 ton (2,240 pounds)
Body weight adoption: The Victorian era (1837-1901) saw the stone become the standard for human weighing. Bathroom scales, medical records, and public health data used stones and pounds.
Metrication and Persistence (1965-Present)
The Weights and Measures Act 1965: The UK officially adopted the metric system, making kilograms the legal unit for trade. However, the Act exempted personal weighing—bathroom scales could continue showing stones.
Why the exemption?
- Cultural resistance: Brits refused to abandon stones for body weight
- Economic lobbying: Scale manufacturers didn't want to retool
- Medical inertia: NHS records already used stones; conversion would be costly
The result: 60+ years later, the stone persists:
- Bathroom scales: Default to stones in the UK (even modern digital ones)
- NHS medical records: Still record patient weight in stones/pounds
- Weight loss programs: Slimming World, Weight Watchers UK use stones
- Media: British newspapers report celebrity weight in stones
- Sports: Boxing, horse racing, rowing use stones for weight classes
Ireland's experience: Ireland officially adopted metric units in 2005, but the stone remains common for body weight, especially among older generations.
Generational divide:
- Older Brits (60+): Think exclusively in stones
- Middle-aged (30-60): Bilingual (stones and kilograms)
- Younger (<30): Increasingly use kilograms, but still understand stones
Cultural Tenacity
The stone is the most persistent Imperial unit in British daily life, outlasting:
- Fahrenheit: Replaced by Celsius (weather, ovens)
- Inches/feet for height: Partially replaced by metres (though feet still common)
- Pints: Milk sold in litres (though beer still sold in pints!)
- Miles: Road signs still use miles (the UK never fully switched)
Why the stone survives:
- Emotional connection: Body weight is personal; changing units feels invasive
- Convenient range: For adults, weight is 8-20 stones (easy to remember vs. 50-127 kg)
- Medical exemption: Doctors use stones, so patients use stones
- Social reinforcement: Everyone around you uses stones, so you do too
-
Metric System Origins: The microgram is derived from the gram, a base unit in the early metric system defined in the late 18th century during the French Revolution (1790s).
-
Prefix Development: The prefix "micro-" (symbol: µ) was formalized in the late 19th century as part of the systematic development of metric prefixes to indicate a factor of 10⁻⁶ (one millionth).
-
Scientific Need: As analytical chemistry and biology advanced in the 19th and early 20th centuries, scientists needed to measure increasingly smaller masses - leading to widespread adoption of the microgram.
-
Pharmaceutical Revolution: The microgram became critically important in the 20th century with:
- Development of potent hormones (thyroid, insulin)
- Discovery of vitamins requiring trace amounts
- Creation of modern pharmaceuticals with precise dosing
- Antibiotics and specialized medications
-
Vitamin Discovery Era (1910s-1940s):
- Scientists discovered vitamins needed in microgram quantities
- Vitamin B12, biotin, folate measured in µg
- Nutrition labels began using micrograms
- Public health campaigns addressed micronutrient deficiencies
-
Symbol Standardization:
- µg adopted as standard scientific notation
- mcg introduced in medical settings to prevent confusion (µ can look like m if handwritten poorly)
- Both symbols officially recognized and equivalent
-
Modern Usage: Today, micrograms are essential in:
- Pharmaceutical dosing (especially endocrinology)
- Nutritional labeling (vitamins, minerals)
- Environmental monitoring (air/water quality)
- Toxicology and forensic science
- Analytical chemistry (trace analysis)
Common Uses and Applications: stones vs micrograms
Explore the typical applications for both Stone (imperial/US) and Microgram (metric) to understand their common contexts.
Common Uses for stones
1. Body Weight Measurement
The stone is the unit for body weight in the UK and Ireland.
Bathroom scales:
- Display: "11 st 7 lb" (digital) or analog dial with stone markings
- Dual units: Many scales toggle between st/lb and kg
- Default: Stones for UK-sold scales, even from international brands
Weighing yourself:
- British: "I'm 12 stone 3"
- American: "I'm 171 pounds"
- European: "I'm 78 kilograms"
Weight goals:
- "I want to lose a stone" = 14-pound goal
- "I'm aiming for 10 stone" = target weight
- "I've gained half a stone" = 7-pound increase
2. Medical and Healthcare
NHS patient records: British hospitals and GPs record weight in stones/pounds (with kg conversion).
Medical forms:
- Pre-op questionnaires: "Weight: __ st __ lb"
- Prescription dosing: Sometimes based on weight (converted to kg for calculations)
- Anesthesia planning: Weight in stones converted to kg for drug dosages
Maternity care:
- Booking appointment: "What was your pre-pregnancy weight?" (stones)
- Pregnancy weight tracking: "You've gained 2 stone, which is healthy"
- Post-natal: "Most women lose 1-2 stone in the first weeks"
Mental health context: Eating disorder treatment tracks weight changes in stones (e.g., anorexia recovery: "gained 1 stone to 7 stone 10").
3. Weight Loss and Fitness
Slimming clubs:
- Slimming World, Weight Watchers UK: Weigh-ins in stones
- Awards: "Half-stone hero," "Stone club," "3-stone milestone"
- Targets: "Lose 10% of body weight" (e.g., 1.5 stone from 15 stone start)
Fitness apps (UK versions):
- MyFitnessPal UK: Input weight in stones
- Fitbit/Garmin: UK users set goals in stones
- Weight tracking graphs: Y-axis shows stones, not kg
Personal trainers: British trainers discuss client progress in stones: "You've dropped from 14 stone to 12 stone 8—fantastic!"
4. Sports Weight Classes
Boxing: British boxing traditionally used stones for weight classes (now officially kilograms, but stones still common in commentary).
Horse racing:
- Jockey weights: Includes jockey + saddle + lead weights to meet required "riding weight"
- Handicapping: Horses carry different weights (in stones) to equalize competition
- Penalties: "Carrying 9 stone 7" vs. "Carrying 10 stone" affects race outcomes
Rowing: Lightweight rowers must weigh under certain stone limits (now metric, but historically stones).
5. Everyday Conversation
The stone pervades British informal speech:
Common phrases:
- "I'm 11 stone, give or take" = approximate weight
- "She must be 10 stone soaking wet" = very light
- "He's put on a stone since Christmas" = seasonal weight gain
- "I haven't been 9 stone since I was 15!" = nostalgic reference
Social etiquette:
- It's impolite to ask someone's weight directly, but acceptable to discuss your own
- Women might say "I'm trying to get back to 9 stone" (goal weight)
6. Media and Entertainment
British TV shows:
- Reality TV: "Love Island" contestants' weights discussed in tabloids (stones)
- Medical shows: "Embarrassing Bodies" references patient weight in stones
- Game shows: "The Biggest Loser UK" tracked loss in stones
Newspapers and magazines:
- Celebrity weight speculation: "Has she lost 2 stone?"
- Health articles: "How to lose half a stone by summer"
- Success stories: "I lost 8 stone and transformed my life!"
7. Historical and Cultural References
Literature: Victorian novels reference weight in stones:
- Dickens, Austen rarely mention specific weights (impolite)
- 20th-century literature: "She was a strapping girl of 12 stone"
British humor: Comedians joke about weight in stones:
- "I'm not overweight, I'm just undertall for my 14 stone!"
Generational markers:
- Older Brits: "When I got married, I was 8 stone"
- Modern comparison: "That's only 112 pounds—too thin by today's standards!"
When to Use micrograms
The microgram is essential for measuring extremely small quantities across multiple fields:
Medicine & Pharmaceuticals
Measuring dosages of potent medications and hormones where milligrams would be too large a unit. Critical for endocrinology, psychiatry, and specialized therapeutics.
Why micrograms matter:
- Potent drugs have narrow therapeutic windows
- Prevents overdose from rounding errors
- Allows fine-tuning of hormone replacement
- Essential for pediatric dosing
Common medications in µg:
- Thyroid hormones (25-200 µg)
- Birth control (15-35 µg estrogen)
- Vitamin B12 supplements (100-1,000 µg)
- Folic acid (400-800 µg)
- Digoxin (62.5-250 µg)
⚠️ Safety: Pharmacists use mcg (not µg) on prescriptions to prevent µ being misread as m.
Convert medication doses: µg to mg | mg to µg
Nutrition
Specifying amounts of trace minerals and vitamins in food, especially those needed in very small quantities but essential for health.
Nutrients measured in µg:
- Vitamin B12 (2.4 µg/day)
- Vitamin D (10-20 µg/day)
- Vitamin K (90-120 µg/day)
- Folate (400 µg/day)
- Selenium (55 µg/day)
- Biotin (30 µg/day)
Why µg for nutrition:
- Daily requirements are very small
- Prevents decimal errors (easier than 0.0024 g)
- International standard for supplement labeling
- Matches medical terminology
Food Fortification:
- Breakfast cereals: Fortified with µg amounts of B vitamins
- Milk: Vitamin D added in µg
- Salt: Iodine fortification (45-100 µg per gram of salt)
Chemistry & Biology
Quantifying trace amounts of substances in experiments, especially in analytical chemistry, biochemistry, and molecular biology.
Laboratory Applications:
- Sample preparation: Weighing µg of rare compounds
- Protein quantification: Bradford/BCA assays use µg protein
- DNA/RNA: Quantified in µg for PCR, sequencing
- HPLC/GC: Injection standards in µg amounts
- Mass spectrometry: Detection at µg to pg levels
Biochemical Standards:
- Enzyme activity: Units per µg protein
- Cell culture: Growth factors at 1-100 µg/mL
- Antibody concentration: Often µg/mL
Environmental Science
Measuring concentrations of pollutants or contaminants in air, water, and soil at parts-per-million (ppm) or parts-per-billion (ppb) levels.
Environmental Monitoring:
-
Air quality: µg/m³ (micrograms per cubic meter)
- PM2.5 particulates
- Heavy metals (lead, mercury)
- Volatile organic compounds (VOCs)
-
Water quality: µg/L (micrograms per liter = ppb)
- Arsenic, lead, mercury in drinking water
- Pesticide residues
- Pharmaceutical contaminants
- Microplastics
-
Soil contamination: µg/kg (micrograms per kilogram = ppb)
- Heavy metal contamination
- Persistent organic pollutants
Regulatory Standards:
- EPA sets limits in µg/m³ or µg/L
- WHO guidelines use µg measurements
- EU environmental regulations
Toxicology and Forensics
Measuring extremely small amounts of toxic substances, drugs, or poisons in biological samples.
Forensic Toxicology:
- Blood drug levels (µg/L)
- Urine drug screening (µg/mL)
- Hair analysis (µg/mg hair)
- Tissue samples (µg/g tissue)
Clinical Toxicology:
- Heavy metal poisoning (blood lead: µg/dL)
- Drug overdose assessment
- Therapeutic drug monitoring
- Poison detection
Detection Limits:
- Modern instruments: Can detect picograms (0.001 µg)
- High sensitivity needed for trace toxins
Research and Development
Pharmaceutical R&D, materials science, and nanotechnology use micrograms for:
- Drug formulation studies
- Nanoparticle synthesis
- Catalyst development
- Biosensor fabrication
- Quality control testing
Use our weight converter for scientific conversions.
Additional Unit Information
About Stone (st)
1. How many pounds are in a stone?
Exactly 14 pounds.
This is a defined constant. There are no regional variations—1 stone always equals 14 pounds in any context.
Calculation examples:
- 5 stone = 5 × 14 = 70 pounds
- 12 stone = 12 × 14 = 168 pounds
- 0.5 stone = 0.5 × 14 = 7 pounds
2. Is the stone used outside the UK and Ireland?
Rarely. The stone is almost exclusive to the UK and Ireland.
Usage by country:
- UK: Dominant for body weight (even with official metrication)
- Ireland: Common, especially among older generations
- Canada, Australia, New Zealand: Not used (fully metric)
- United States: Not used (pounds only)
- Rest of world: Not used (metric)
Exception: British expats abroad sometimes use stones, and international weight loss forums may reference stones when discussing UK participants.
3. Why is it called a stone?
Historical practice: Actual stones were used as standardized weights in medieval markets.
How it worked:
- A community selected a reference stone of agreed weight
- The stone was kept in the marketplace (sometimes literally built into a wall)
- Merchants used the reference stone on balance scales to verify weights
- Different stones existed for different commodities (wool stone, meat stone, etc.)
Modern name: The unit name "stone" is a fossil of this practice, long after actual stones stopped being used.
4. How do you convert stone to kilograms?
Formula:
Kilograms = Stone × 6.35029318
Quick approximation:
Kilograms ≈ Stone × 6.35 (good to 3 decimal places)
Examples:
- 10 stone × 6.35 = 63.5 kg
- 12 stone × 6.35 = 76.2 kg
- 15 stone × 6.35 = 95.25 kg
Online tools: Most conversion sites and apps include stone ↔ kilogram calculators.
5. How do British people talk about their weight?
Typical format: "I'm X stone Y pounds" or "I'm X stone Y"
Examples:
- "I'm 11 stone 7" = 11 stone + 7 pounds = 161 lb = 73 kg
- "I'm just over 12 stone" = slightly more than 168 lb
- "I'm nearly 10 stone" = approaching 140 lb
Rarely said:
- "I'm 11.5 stone" (uncommon—people say "11 stone 7" instead)
- "I'm 161 pounds" (too American—Brits don't think in pounds alone)
- "I'm 73 kilograms" (used by younger generations, but less common)
Conversational weight: Discussing weight is somewhat taboo, so people often avoid specifics: "I need to lose a bit of weight" rather than "I need to drop from 13 to 11 stone."
6. Do British bathroom scales show kilograms?
Yes, most modern scales show both.
Typical features:
- Default: Stones and pounds (st/lb)
- Toggle button: Switch to kilograms
- Dual display: Some show both simultaneously
Older scales: Analog scales from before 2000 often show stones only.
Buying scales in the UK: Even international brands (Fitbit, Garmin) sell UK-specific versions that default to stones.
7. Will the UK ever stop using stones?
Unlikely in the near future.
Reasons for persistence:
- Cultural attachment: Body weight is personal; people resist change
- Legal exemption: Personal weighing scales exempt from trade regulations
- NHS inertia: Changing medical records costly
- Generational use: Older generations use stones exclusively
- No enforcement: No push to mandate kilograms for personal use
Trend: Younger Brits (under 30) increasingly use kilograms, especially those who travel or use fitness apps with international audiences. However, the stone will likely persist for decades among older populations.
Comparison: Similar to Fahrenheit in the US—officially discouraged but culturally entrenched.
8. What is a "half stone"?
Half stone = 7 pounds = 3.175 kg
Usage:
- Weight loss: "I've lost half a stone" = 7 lb loss
- Weight gain: "I've put on half a stone over Christmas" = 7 lb gain
- Milestones: "Half-stone club" in weight loss programs
Why significant? Half a stone is a noticeable weight change—enough to affect how clothes fit and how you feel, but achievable in 3-7 weeks of dieting (at 1-2 lb/week loss).
9. How do you write stone and pounds?
Common formats:
Formal:
- "11 stone 7 pounds"
- "11 st 7 lb"
Informal:
- "11 stone 7"
- "11st 7lb" (no spaces)
- "11-7" (very casual, context-dependent)
Avoid:
- "11.7 stone" (ambiguous—could mean 11 stone 7 lb or 11 stone 9.8 lb)
- "11/7 st" (confusing notation)
Medical records: NHS typically uses "st/lb" format: "Patient weight: 12 st 3 lb"
10. Why do Americans not use stone?
The United States never adopted the stone for body weight.
Historical reasons:
- Colonial divergence: By the time the stone standardized in Britain (1824), the US had already established pounds as the body weight unit
- Decimal preference: Americans favored simpler base-10 systems where possible
- No cultural push: No equivalent to UK's Victorian-era adoption of stones for weighing people
Result: Americans think in pounds only:
- "I weigh 180 pounds" (no stones)
- Weight loss: "I lost 30 pounds" (not "2 stone 2 pounds")
Canadian note: Canada officially metricated in the 1970s and uses kilograms, not stones or pounds (though older Canadians may still think in pounds).
11. Is stone a legal unit?
Yes, in the UK and Ireland, but with restrictions.
Legal status:
- Personal use: Fully legal (bathroom scales, self-weighing)
- Trade: Must use metric (kilograms) for selling goods by weight
- Medical: Allowed in patient records (NHS uses stones)
Weights and Measures Act: Kilograms are the legal unit for commerce, but stones remain legal for "non-trade" purposes (personal weighing, medical records).
Comparison: Similar to miles on UK road signs—officially metric, but exceptions preserve traditional units in specific contexts.
12. How much is a stone in other historical weight units?
Stone in troy and apothecary systems:
Troy weight (precious metals):
- 1 stone (avoirdupois) = 14 pounds (avoirdupois)
- 1 pound (avoirdupois) = 7,000 grains
- 1 stone = 98,000 grains (troy)
- 1 troy pound = 5,760 grains
- 1 stone ≈ 17.01 troy pounds
Apothecaries' weight (pharmacy):
- Same grain as troy and avoirdupois (64.79891 mg)
- 1 stone = 98,000 grains (apothecaries')
Why this matters: Historically, pharmacists used apothecaries' weights, so understanding stone conversions was important for dosing medicines based on body weight.
About Microgram (µg)
How many micrograms are in a milligram?
There are 1,000 micrograms (µg) in 1 milligram (mg).
Conversion:
- 1 mg = 1,000 µg
- To convert mg to µg: multiply by 1,000
- To convert µg to mg: divide by 1,000
Examples:
- 0.5 mg = 500 µg
- 1.5 mg = 1,500 µg
- 0.025 mg = 25 µg
- 10 mg = 10,000 µg
Memory aid: "Milli" is bigger than "micro" - mg is 1,000 times larger than µg.
Use our mg to µg converter for instant conversions.
How many micrograms are in a gram?
There are 1,000,000 micrograms (µg) in 1 gram (g).
Calculation: 1 g = 1,000 mg, and 1 mg = 1,000 µg, therefore: 1 g = 1,000 × 1,000 µg = 1,000,000 µg
Conversion:
- 1 g = 1,000,000 µg
- To convert g to µg: multiply by 1,000,000
- To convert µg to g: divide by 1,000,000
Examples:
- 0.001 g = 1,000 µg
- 0.01 g = 10,000 µg
- 0.1 g = 100,000 µg
- 1 g = 1,000,000 µg
Perspective: A grain of salt (~1 mg) contains ~1,000 µg.
What is the symbol for microgram?
The standard symbol is µg (using the Greek letter µ, pronounced "mu").
Alternative symbol: mcg (used especially in medical contexts)
Why two symbols?:
- µg: Standard scientific notation, internationally recognized
- mcg: Safer in medical prescriptions - prevents µ being misread as m
- Both mean exactly the same thing: 1 µg = 1 mcg
Safety issue:
- Handwritten µ can look like m
- "µg" misread as "mg" = 1,000x dosing error
- Medical professionals prefer "mcg" to prevent fatal errors
How to type µ:
- Mac: Option + M
- Windows: Alt + 230
- Or just type "mcg" in medical contexts
Is µg the same as mcg?
Yes! µg and mcg mean exactly the same thing.
- µg: Microgram (using Greek letter µ)
- mcg: Microgram (using letters m-c-g)
- Both = 0.001 mg = 0.000001 g
Why both exist?:
- µg: Standard in science, chemistry, environmental science
- mcg: Preferred in medicine/pharmacy for safety
- Prevents µ being misread as m (which would be mg)
Where you'll see each:
- µg: Scientific papers, environmental reports, lab results
- mcg: Prescription bottles, medical records, pharmacy labels
- Both: Nutrition labels (may show either or both)
Important: Always verify which unit - never assume!
How much is 1 microgram visually?
1 microgram is EXTREMELY small - too small to see with the naked eye.
Visual comparisons:
- 1,000 µg = 1 mg = 1 grain of table salt
- 100 µg = Approximate weight of a human red blood cell
- 10 µg = Large grain of pollen
- 1 µg = Small speck of dust
Perspective:
- 1 paperclip ≈ 1,000,000 µg (1 gram)
- 1 grain of salt ≈ 1,000 µg (1 mg)
- 1 eyelash ≈ 10-100 µg
- 1 human hair (1 cm) ≈ 60-90 µg
For medication:
- A typical Vitamin B12 tablet (1,000 µg) looks like any small pill
- The active ingredient weighs 1 mg
- The rest is filler/binder
You cannot "see" individual micrograms - you need a precision scale to measure them accurately.
What medications are dosed in micrograms?
Many potent medications use microgram dosing:
Thyroid Hormones (most common):
- Levothyroxine: 25-200 µg
- Liothyronine: 5-50 µg
Hormonal Medications:
- Birth control pills: 15-35 µg estrogen
- Testosterone: Some formulations
Cardiovascular:
- Digoxin: 62.5-250 µg
- Clonidine: 100-600 µg
Pain Management:
- Fentanyl: Patches deliver µg/hour
- (Fentanyl is EXTREMELY potent - µg doses)
Vitamins (technically supplements):
- Vitamin B12: 100-5,000 µg
- Vitamin D: 10-125 µg (400-5,000 IU)
- Folate: 400-800 µg
- Biotin: 30-10,000 µg
Why micrograms?:
- Very potent drugs need small doses
- Narrow therapeutic window
- Prevents overdose from measurement errors
⚠️ Safety: These medications have microgram-level dosing precisely because they're potent. Never adjust dose without medical supervision.
How do I measure micrograms at home?
Short answer: You generally CAN'T and SHOULDN'T measure micrograms at home.
Why not?:
- Kitchen scales: Accurate to 1 gram (1,000,000 µg) - NOT precise enough
- Jewelry scales: Accurate to 0.01-0.1 g (10,000-100,000 µg) - still not precise
- Milligram scales: Accurate to 1 mg (1,000 µg) - closer but not µg-level
- Microgram precision: Requires laboratory analytical balance ($1,000-$10,000)
For Medications:
- ✅ Use pre-measured tablets/capsules - safest option
- ✅ Follow prescription exactly - don't compound at home
- ✅ Liquid medications: Use provided dropper/syringe
- ❌ Never try to measure powder medications at home
For Supplements:
- Buy pre-dosed pills (e.g., 1,000 µg B12 tablets)
- Use products with certified dosing
- Don't buy raw powder unless you're a lab
If you need microgram precision:
- Laboratory analytical balance required
- Calibrated weights for accuracy
- Controlled environment (no air currents)
- Cost: $1,000+ for quality balance
Safety warning: ⚠️ For medications, NEVER attempt home measurement. Fatal dosing errors possible. Always use professionally prepared medications.
What's the difference between µg/mL and mg/L?
They are exactly the same!
µg/mL = mg/L (both equal parts per million in water)
Why?:
- 1 mL = 0.001 L (or 1 L = 1,000 mL)
- 1 mg = 1,000 µg
- Therefore: 1 mg/L = 1,000 µg/1,000 mL = 1 µg/mL
Examples:
- Lead in water: 15 µg/L = 0.015 mg/L
- Drug concentration: 100 µg/mL = 100 mg/L
- Vitamin solution: 50 µg/mL = 50 mg/L
Common uses:
- µg/mL: Laboratory concentrations, drug solutions
- mg/L: Environmental standards, water quality
- Both: Used interchangeably depending on field
Parts per million (ppm):
- In water: 1 ppm = 1 mg/L = 1 µg/mL
- In air: 1 ppm is different (depends on molecular weight)
How many IU is a microgram?
It depends on which vitamin! IU (International Units) convert differently for each substance.
Vitamin D (most common):
- 1 µg = 40 IU
- 1 IU = 0.025 µg
Common Vitamin D conversions:
- 400 IU = 10 µg
- 800 IU = 20 µg
- 1,000 IU = 25 µg
- 2,000 IU = 50 µg
- 5,000 IU = 125 µg
Vitamin A (retinol):
- 1 IU ≈ 0.3 µg retinol
- 1 µg retinol ≈ 3.33 IU
Vitamin E (α-tocopherol):
- 1 IU ≈ 0.67 mg α-tocopherol
- (Note: mg not µg for Vitamin E!)
Why different?:
- IU measures biological activity, not mass
- Each vitamin has different potency
- Historical measurement system
- Modern labels often show both µg and IU
Tip: Check supplement labels - most show both µg and IU for clarity.
What is µg/dL in blood tests?
µg/dL = micrograms per deciliter - commonly used in blood test results.
What it means:
- Concentration of a substance in blood
- 1 dL = 100 mL (1 deciliter = 10th of a liter)
- µg/dL tells you: micrograms per 100 milliliters of blood
Common blood tests using µg/dL:
Blood Lead Level:
- Normal: <5 µg/dL
- Elevated: 5-10 µg/dL
- High: >10 µg/dL (concern)
- Toxic: >45 µg/dL
Blood Glucose (note: mg/dL, not µg/dL):
- Normal fasting: 70-100 mg/dL
- (This is milligrams, not micrograms!)
Iron/Ferritin: Sometimes reported in µg/dL Vitamin B12: Often ng/mL or pg/mL (nanograms/picograms)
Conversion:
- 1 µg/dL = 10 µg/L
- 1 µg/dL = 0.01 mg/L
- 1 µg/dL = 10 ng/mL
Clinical significance:
- Reference ranges vary by lab
- Always check lab's normal range
- Consult healthcare provider for interpretation
Note: µg/dL is different from µg/mL:
- 1 µg/dL = 0.01 µg/mL (100 times smaller)
Conversion Table: Stone to Microgram
| Stone (st) | Microgram (µg) |
|---|---|
| 0.5 | 3,175,146,590 |
| 1 | 6,350,293,180 |
| 1.5 | 9,525,439,770 |
| 2 | 12,700,586,360 |
| 5 | 31,751,465,900 |
| 10 | 63,502,931,800 |
| 25 | 158,757,329,500 |
| 50 | 317,514,659,000 |
| 100 | 635,029,318,000 |
| 250 | 1,587,573,295,000 |
| 500 | 3,175,146,590,000 |
| 1,000 | 6,350,293,180,000 |
People Also Ask
How do I convert Stone to Microgram?
To convert Stone to Microgram, enter the value in Stone in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our weight converter page to convert between other units in this category.
Learn more →What is the conversion factor from Stone to Microgram?
The conversion factor depends on the specific relationship between Stone and Microgram. 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 Microgram back to Stone?
Yes! You can easily convert Microgram back to Stone by using the swap button (⇌) in the calculator above, or by visiting our Microgram to Stone converter page. You can also explore other weight conversions on our category page.
Learn more →What are common uses for Stone and Microgram?
Stone and Microgram are both standard units used in weight measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our weight converter for more conversion options.
For more weight conversion questions, visit our FAQ page or explore our conversion guides.
Helpful Conversion Guides
Learn more about unit conversion with our comprehensive guides:
📚 How to Convert Units
Step-by-step guide to unit conversion with practical examples.
🔢 Conversion Formulas
Essential formulas for weight and other conversions.
⚖️ Metric vs Imperial
Understand the differences between measurement systems.
⚠️ Common Mistakes
Learn about frequent errors and how to avoid them.
All Weight Conversions
Other Weight Units and Conversions
Explore other weight units and their conversion options:
- Kilogram (kg) • Stone to Kilogram
- Gram (g) • Stone to Gram
- Milligram (mg) • Stone to Milligram
- Pound (lb) • Stone to Pound
- Ounce (oz) • Stone to Ounce
- Ton (metric) (t) • Stone to Ton (metric)
- Ton (US) (ton) • Stone to Ton (US)
- Ton (UK) (long ton) • Stone to Ton (UK)
- Carat (ct) • Stone to Carat
- Slug (sl) • Stone to Slug
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 — US standards for weight and mass measurements
International Organization for Standardization — International standard for mechanics quantities
Last verified: December 3, 2025