Last updated: February 2026

Kg to Stone Calculator - Weight Conversion

Free, accurate, instant results. Updated for 2025. No signup required.

Quick Weight Converter

Kilograms to Stone & Pounds

Stone & Pounds to Kilograms

Quick Reference Conversion Tables

Kilograms to Stone

Kilograms Stone
50 kg7.87 st
55 kg8.66 st
60 kg9.45 st
65 kg10.24 st
70 kg11.02 st
75 kg11.81 st
80 kg12.60 st
85 kg13.39 st
90 kg14.17 st
100 kg15.75 st

Stone to Kilograms

Stone Kilograms
8 st50.80 kg
9 st57.15 kg
10 st63.50 kg
11 st69.85 kg
12 st76.20 kg
13 st82.55 kg
14 st88.90 kg
15 st95.25 kg
16 st101.60 kg
20 st127.01 kg

Understanding Weight Conversions in the UK

What is a Stone?

A stone is a traditional British unit of weight equal to 14 pounds or 6.35029 kilograms. It's been used in the UK for centuries and remains the preferred unit for measuring human body weight, even though the metric system was officially adopted in 1965.

The stone measurement has historical roots dating back to medieval times when different regions had varying definitions. The standardization to 14 pounds occurred in the 14th century and has remained constant since then.

Conversion Formulas

Kilograms to Stone:

Stone = Kilograms ÷ 6.35029

Stone to Kilograms:

Kilograms = Stone × 6.35029

Stone and Pounds to Kilograms:

Kilograms = (Stone × 6.35029) + (Pounds × 0.453592)

NHS Weight Guidelines

The NHS uses BMI (Body Mass Index) to assess healthy weight ranges. While healthcare professionals typically use kilograms, understanding your weight in stone can be helpful for everyday tracking:

  • Underweight (BMI below 18.5): May indicate nutritional deficiency - consult your GP
  • Healthy weight (BMI 18.5-24.9): Optimal range for most adults
  • Overweight (BMI 25-29.9): Increased health risks - lifestyle changes recommended
  • Obese (BMI 30+): Significant health risks - medical support advised

For a 5'9" (175cm) adult, healthy weight ranges from approximately 9 stone (57kg) to 12 stone 7 pounds (79kg). However, these are general guidelines - factors like muscle mass, bone density, and overall health should also be considered.

Practical Weight Conversion Tips

Quick Mental Conversions

  • 1 stone ≈ 6.35 kg (remember 6.35 for accuracy)
  • 10 stone ≈ 63.5 kg (multiply by 10 for round numbers)
  • 1 kg ≈ 2.2 pounds (useful for small conversions)
  • 14 pounds = 1 stone exactly

Common Weight Measurements in UK Healthcare

UK healthcare settings primarily use metric measurements:

  • GP Surgeries: Digital scales showing both kg and stone/pounds
  • Hospitals: Primarily kilograms for medical accuracy
  • Pharmacies: Medicine dosages calculated in kg
  • Newborn Babies: Weighed in kilograms and grams (e.g., 3.5kg), though parents often convert to pounds/ounces

Weight Conversion for Different Purposes

Personal Weight Tracking

Most UK bathroom scales display both units. Track progress in whichever unit feels most natural, but be consistent for accurate comparison.

Medical Documentation

NHS patient records use kilograms. Know both your kg and stone weight for consultations.

Fitness Goals

Gym equipment and fitness apps often use kg. Stone is useful for long-term tracking and discussing progress with others.

Historical Context

The stone has been used in Britain since at least the 14th century. Originally, different commodities had different stone weights - wool was measured in 14-pound stones, while meat used 8-pound stones. The 14-pound stone became standard for human body weight.

Despite the UK officially adopting the metric system in 1965, stone remains deeply embedded in British culture. A 2020 survey found that over 70% of UK adults prefer to express their body weight in stone and pounds rather than kilograms.

Weight Loss and Gain Tracking

When monitoring weight changes, small measurements matter:

  • 1 pound (0.45 kg): Minimum detectable change on most scales
  • 1-2 pounds per week: NHS recommended safe weight loss rate
  • Half a stone (7 pounds/3.2 kg): Noticeable difference in clothing fit
  • 1 stone (6.35 kg): Significant weight change, usually requiring new clothing sizes

Weight Fluctuations are Normal

Your weight can fluctuate by 2-4 pounds (0.9-1.8 kg) daily due to water retention, food intake, and hormonal changes. For accurate tracking, weigh yourself at the same time of day, ideally in the morning before eating.

International Perspective

The stone is unique to the UK and Ireland. When traveling or working internationally:

  • USA: Uses pounds only (no stones)
  • Most of Europe: Uses kilograms exclusively
  • Australia/Canada: Officially metric (kg) but some older citizens still use imperial units
  • Ireland: Uses stone and kg interchangeably, similar to UK

Accuracy Considerations

Our calculator uses the precise conversion factor of 1 stone = 6.35029318 kilograms. For practical purposes:

  • Results rounded to 2 decimal places are accurate for all everyday uses
  • Medical dosing requires kilogram measurements to 1 decimal place
  • Home scales typically accurate to ±0.1 kg or ±0.2 pounds
  • Professional medical scales accurate to ±0.05 kg

Children's Growth Tracking

The NHS provides growth charts (centile charts) for children using both kilograms and stone/pounds. Parents should track their child's weight regularly:

  • Newborns: Average birth weight 7.5 pounds (3.4 kg)
  • 6 months: Typically double birth weight
  • 1 year: Typically triple birth weight
  • Ages 2-18: Follow NHS growth charts, checking annually at minimum

Pregnancy Weight Guidelines

The NHS recommends weight monitoring during pregnancy. Average healthy weight gain:

  • First trimester: 1-4 pounds (0.5-2 kg)
  • Total pregnancy: 25-35 pounds (11-16 kg) for normal BMI
  • Underweight pre-pregnancy: 28-40 pounds (13-18 kg)
  • Overweight pre-pregnancy: 15-25 pounds (7-11 kg)

How to Use This Calculator

Our kg to stone converter is designed to be as straightforward as possible, giving you instant results without any need to press a button. Here is how to get the most out of it:

Converting Kilograms to Stone and Pounds

Simply type your weight in kilograms into the Kilograms (kg) field at the top of the calculator. As soon as you enter a number, the result appears instantly below, showing your weight expressed in whole stones and remaining pounds. You will also see the total as a decimal stone value and as a total in pounds only, so you have every format you might need.

Converting Stone and Pounds to Kilograms

If you already know your weight in imperial units and need the metric equivalent, scroll down to the Stone & Pounds to Kilograms section. Enter the number of stones in the first box and any remaining pounds in the second. The converter updates automatically, displaying your weight in kilograms together with a total pounds figure.

Tips for Accurate Results

  • You can enter decimal values (for example, 72.5 kg) for greater precision.
  • The pounds field accepts values up to 13.9 because 14 pounds equals the next whole stone.
  • Hit the Reset Calculator button to clear all fields and start a fresh conversion.
  • Results update in real time -- there is no need to click a separate calculate button.

Whether you are checking your weight after a GP appointment, tracking fitness progress, or converting for an overseas form, this tool handles it all in seconds.

Worked Examples

Below are four step-by-step examples showing how to convert kilograms to stones and pounds by hand. The formula used is:

kg ÷ 6.35029 = total stones (decimal) → whole stones + (decimal × 14) = remaining pounds

Example 1: 70 kg (average UK male)

  1. Divide by the conversion factor: 70 ÷ 6.35029 = 11.023 stone
  2. Take the whole number: 11 stone
  3. Multiply the remainder by 14: 0.023 × 14 = 0.3 lbs

Result: 70 kg = 11 stone 0.3 lbs

Example 2: 55 kg (average UK female)

  1. Divide by the conversion factor: 55 ÷ 6.35029 = 8.661 stone
  2. Take the whole number: 8 stone
  3. Multiply the remainder by 14: 0.661 × 14 = 9.3 lbs

Result: 55 kg = 8 stone 9.3 lbs

Example 3: 90 kg

  1. Divide by the conversion factor: 90 ÷ 6.35029 = 14.173 stone
  2. Take the whole number: 14 stone
  3. Multiply the remainder by 14: 0.173 × 14 = 2.4 lbs

Result: 90 kg = 14 stone 2.4 lbs

Example 4: 100 kg

  1. Divide by the conversion factor: 100 ÷ 6.35029 = 15.747 stone
  2. Take the whole number: 15 stone
  3. Multiply the remainder by 14: 0.747 × 14 = 10.1 lbs

Result: 100 kg = 15 stone 10.1 lbs

You can verify any of these by entering the kilogram value into the calculator above. The results update instantly, so there is no need to do the arithmetic yourself.

Quick Reference Table: 50 kg to 120 kg

The table below covers the most commonly looked-up weight range in 5 kg increments. All values are calculated using the precise conversion factor of 1 stone = 6.35029 kg and 1 stone = 14 pounds.

Kilograms Stone & Pounds Decimal Stone
50 kg7 st 12.2 lbs7.87 st
55 kg8 st 9.3 lbs8.66 st
60 kg9 st 6.3 lbs9.45 st
65 kg10 st 3.3 lbs10.24 st
70 kg11 st 0.3 lbs11.02 st
75 kg11 st 11.3 lbs11.81 st
80 kg12 st 8.4 lbs12.60 st
85 kg13 st 5.4 lbs13.39 st
90 kg14 st 2.4 lbs14.17 st
95 kg14 st 13.4 lbs14.96 st
100 kg15 st 10.5 lbs15.75 st
105 kg16 st 7.5 lbs16.53 st
110 kg17 st 4.5 lbs17.32 st
115 kg18 st 1.5 lbs18.11 st
120 kg18 st 12.6 lbs18.90 st

Need a value that falls between these increments? Enter it directly into the calculator above for an instant, precise result.

Why the UK Uses Stones

The stone is one of the oldest surviving units of measurement in everyday British life. Its origins stretch back to the medieval era, when traders across England, Scotland and Wales needed a standard way to weigh goods such as wool, grain and meat. Although different trades initially used stone weights of varying sizes -- a wool stone was 14 pounds while a butcher's stone could be 8 pounds -- an Act of Parliament in 1389 standardised the stone at exactly 14 pounds (6.35029 kilograms) for all purposes.

When the UK formally adopted the metric system in 1965 under the Weights and Measures Act, kilograms became the official unit for trade and commerce. Road signs switched to metric for goods vehicle limits, and supermarkets began labelling produce in grams and kilograms. However, the stone stubbornly survived in one area that legislation could not easily reach: how British people talk about their own body weight.

This sets the UK apart from the rest of the world. The United States uses pounds only -- an American will say they weigh "154 pounds" rather than "11 stone". Continental Europe, Australasia and most of Asia use kilograms exclusively. The UK and Ireland are the only countries where the stone remains in widespread colloquial use for personal weight.

Even the National Health Service reflects this dual system. Official NHS clinical records, prescriptions and medical guidelines use kilograms, yet many patient-facing documents, health screening letters and GP waiting-room posters reference both units. Most bathroom scales sold in UK shops display kilograms on one side and stone-and-pounds on the other.

A YouGov survey found that over 70 percent of British adults still prefer to state their weight in stone and pounds in everyday conversation. For younger generations who grew up with metric education, kilograms are becoming more familiar, but the stone remains deeply embedded in British culture -- from casual pub conversation to newspaper headlines about celebrity weight loss. It is a quintessentially British unit that shows no sign of disappearing any time soon.

Frequently Asked Questions

How many kilograms are in a stone?

One stone equals exactly 6.35029 kilograms. This is the official conversion rate used throughout the UK for weight measurements.

How do I convert kg to stone and pounds?

To convert kg to stone and pounds: 1) Divide kilograms by 6.35029 to get stones. 2) Multiply the decimal part by 14 to get pounds. For example, 70kg = 11.02 stone = 11 stone 0.3 pounds.

What is the NHS recommended healthy weight range?

The NHS recommends maintaining a healthy BMI between 18.5 and 24.9. For a person 5'9" tall, this translates to roughly 9 stone to 12 stone 7 pounds (57-79 kg). Check with your GP for personalized advice.

Why does the UK use stone for weight?

The UK uses stone as a traditional unit of measurement dating back centuries. While officially metric since 1965, stone remains popular for measuring body weight. One stone equals 14 pounds or 6.35029 kilograms.

How accurate is this kg to stone calculator?

This calculator uses the exact conversion factor (1 stone = 6.35029318 kg) and provides results accurate to 2 decimal places, which is more than sufficient for all practical weight measurements.

Can I use this calculator for baby weight?

Yes, this calculator works for all weights including newborns. UK babies are typically weighed in kilograms by healthcare professionals, but parents often prefer to know the weight in pounds and ounces.

What's the difference between stone and pounds?

A stone is a larger unit of weight equal to 14 pounds. In the UK, body weight is commonly expressed as a combination of stones and pounds (e.g., 10 stone 7 pounds) rather than just pounds.

Is stone still used in the UK in 2025?

Yes, stone remains widely used in the UK for measuring personal body weight, despite official metrication. Most UK bathroom scales show both kilograms and stone/pounds, and it's the preferred unit in everyday conversation.

How many pounds are in a stone?

There are exactly 14 pounds in one stone. This has been the standard definition since the 14th century. So if you weigh 10 stone 7 pounds, that equals 147 pounds in total (10 x 14 + 7 = 147).

What does the NHS use - kg or stones?

The NHS officially uses kilograms for all medical records, prescriptions and clinical documentation. However, many patient-facing materials, GP consultations and NHS weight management programmes also reference stones and pounds because most UK patients find it easier to understand their weight in imperial units.

How do I convert stones to kg?

To convert stones to kilograms, multiply the number of stones by 6.35029. For example, 12 stone = 12 x 6.35029 = 76.20 kg. If you also have pounds, convert them separately by multiplying by 0.4536 and add the two results together.

What is a healthy weight in stones?

A healthy weight in stones depends entirely on your height. The NHS uses BMI (Body Mass Index) to determine healthy weight ranges. For example, a 5'6" woman has a healthy range of roughly 8 stone 3 lbs to 11 stone 0 lbs, while a 5'10" man ranges from about 9 stone 6 lbs to 12 stone 10 lbs. Use our BMI calculator for a personalised assessment.

Why doesn't America use stones?

The United States adopted its own version of the imperial system (US customary units) which uses pounds as the primary unit for body weight rather than stones. When America gained independence in the 18th century, it retained pounds but dropped the stone measurement. As a result, Americans express weight purely in pounds -- for example saying "154 pounds" rather than "11 stone" as a Briton would.

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Expert Reviewed — This calculator uses the exact international conversion factor (1 stone = 6.35029318 kg) and is verified against official measurement standards. Last verified: February 2026.

Last updated: February 2026 | Verified with official conversion standards

Pro Tips for Accurate Results
  • Double-check your input values before calculating
  • Use the correct unit format (metric or imperial)
  • For complex calculations, break them into smaller steps
  • Bookmark this page for quick future access
Understanding Your Results

Our Calculator Kg To Stone provides:

  • Instant calculations - Results appear immediately
  • Accurate formulas - Based on official UK standards
  • Clear explanations - Understand how results are derived
  • 2025/26 updated - Using current rates and regulations
Common Questions

Is this calculator free?

Yes, all our calculators are 100% free to use with no registration required.

Are the results accurate?

Our calculators use verified formulas and are regularly updated for accuracy.

Can I use this on mobile?

Yes, all calculators are fully responsive and work on any device.

Practical Example: NHS Weight Categories in Both Units

When your GP discusses your weight, they typically use kilograms in clinical records, but many patients think in stones and pounds. For context, the NHS considers a healthy weight for an average-height woman of 5 feet 4 inches to be between 50 and 68 kilograms, which is 7 stone 12 pounds to 10 stone 10 pounds. For an average-height man of 5 feet 9 inches, the healthy range is approximately 58 to 79 kilograms, or 9 stone 2 pounds to 12 stone 6 pounds. Understanding both measurements helps you interpret NHS weight management advice, health screening letters, and BMI calculations. Luggage weight limits for UK airlines are always in kilograms, with typical cabin bag limits of 7 to 10 kg and checked luggage at 15 to 23 kg. Knowing that one stone equals 6.35 kilograms makes it easy to estimate whether your suitcase is within limits when you only have bathroom scales that display stones.

People Also Ask

Yes, our calculators use verified formulas and are regularly updated with current UK rates and regulations. Results are provided for guidance - always consult professionals for major financial decisions.

Absolutely! All our calculators are fully responsive and work perfectly on smartphones, tablets, and desktops. No app download needed.

No. The conversion factors between kilograms, stones, and pounds are fixed international standards. One stone has equalled exactly 14 pounds since the 14th century, and the kilogram-to-pound ratio (1 lb = 0.45359237 kg) was defined by international agreement in 1959 and has not changed since.

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