Anyone who’s tried to switch between kilograms and stones knows the numbers can get messy. The UK still measures body weight in stones and pounds, while most home scales show kilograms. This guide uses NHS-backed conversion charts to turn kg into stone and pounds in seconds.
1 stone: 14 pounds · 1 stone: 6.35029318 kg · 70 kg: ≈ 11 stone 0.3 lb
Quick snapshot
- 1 stone = 14 pounds exactly (York St John University Nursing Maths Factsheet)
- 1 stone = 6.35029318 kg (University of Manchester Conversion Chart)
- 1 pound = 0.453592 kg (Community Pharmacy Scotland NHS Chart)
- Ideal weight for height and age varies individually; BMI is a guide, not a diagnosis.
- Divide kg by 6.35029318 to get stones (UHSussex NHS Trust Weight Chart)
- Multiply the decimal remainder by 14 to get pounds (Healthy Weight Grampian NHS PDF)
- Example: 70 kg ÷ 6.35029318 = 11.02 stone → 0.02 × 14 = 0.3 lb → 11 st 0.3 lb (NHS BMI Calculator)
- Check your weight against NHS BMI guidelines using stone/pounds.
| Measure | Value | Source |
|---|---|---|
| 1 stone | 14 pounds | York St John |
| 1 stone | 6.35029318 kg | Univ. of Manchester |
| 70 kg in stones | ≈ 11.02 stone (11 st 0.3 lb) | NHS Weight Advice |
| 80 kg in stones | ≈ 12.57 stone (12 st 8 lb) | NHS Grampian |
| 5ft 3 healthy weight (BMI 18.5–24.9) | 7 st 10 lb – 10 st 0 lb | NHS Scotland |
| 60 kg in stones | ≈ 9.45 stone (9 st 6.3 lb) | UHSussex NHS |
| 90 kg in stones | ≈ 14.17 stone (14 st 2.4 lb) | Same sources as above |
| 100 kg in stones | ≈ 15.75 stone (15 st 10.5 lb) | |
| 44.5 kg (exact NHS chart) | 7 stone 0 lb | NHS Scotland Chart |
| 64.1 kg (exact NHS chart) | 10 stone 1 lb | NHS Grampian Chart |
| 35 kg (exact NHS chart) | 5 stone 7 lb | NHS Scotland Chart |
| 58.5 kg (exact NHS chart) | 9 stone 3 lb | NHS Grampian Chart |
How to calculate kg to stone and pounds?
The manual method takes under 30 seconds and uses only two steps, making it reliable when you don’t have a calculator or app handy.
What is the conversion formula?
The exact relationship between the stone and the kilogram is defined by law in the UK. One stone equals exactly 6.35029318 kilograms and 14 pounds (York St John University Nursing Maths Factsheet). One pound equals 0.453592 kilograms (Wikipedia – Stone (unit)).
How to convert kilograms to stones and pounds manually?
- Step 1: Divide your weight in kilograms by 6.35029318. The whole number is your stones.
- Step 2: Take the decimal remainder and multiply it by 14. The result is the pounds portion.
For example, to convert 70 kg: 70 ÷ 6.35029318 = 11.02 stone. The whole part is 11. The decimal 0.02 × 14 = 0.28, rounded to 0.3 lb. So 70 kg ≈ 11 stone 0.3 pounds (NHS Weight Advice).
How to use an online converter?
Many free tools let you enter kg and get stones and pounds instantly. The Stone Synergy converter is one example. NHS Scotland also publishes a Height and Weight Conversion Chart that shows exact equivalents.
What is a stone of weight in kg?
The stone remains the standard for body weight in UK healthcare, gyms, and clothing size guides — tourists and new residents often find it confusing.
How many pounds in a stone?
A stone is a UK unit of mass equal to 14 pounds avoirdupois (Wikipedia – Stone (unit)). It is still used across the UK and Ireland for body weight, but not for most other goods.
How many kilograms in a stone?
Exactly 6.35029318 kg. This number comes from the definition of the pound (0.45359237 kg) times 14 (University of Manchester Conversion Chart).
Common weight conversions (60 kg, 80 kg, etc.)
Here is a spec table for every 5 kg from 50 to 100 kg, converted into stones and pounds using NHS-aligned values.
Eight weight bands, one clear pattern: each 5 kg jump adds roughly 0.79 stone, or about 11 pounds.
| kg | Stones | Stones & Pounds | Approx. Pounds |
|---|---|---|---|
| 50 | 7.87 | 7 st 12.2 lb | 110 |
| 55 | 8.66 | 8 st 9.2 lb | 121 |
| 60 | 9.45 | 9 st 6.3 lb | 132 |
| 65 | 10.24 | 10 st 3.4 lb | 143 |
| 70 | 11.02 | 11 st 0.3 lb | 154 |
| 75 | 11.81 | 11 st 11.3 lb | 165 |
| 80 | 12.60 | 12 st 8.4 lb | 176 |
| 85 | 13.39 | 13 st 5.5 lb | 187 |
| 90 | 14.17 | 14 st 2.4 lb | 198 |
| 95 | 14.96 | 14 st 13.4 lb | 209 |
| 100 | 15.75 | 15 st 10.5 lb | 220 |
The implication: once you know your weight in kg, this table gives an immediate, NHS-compatible read in stones and pounds — no maths required.
How much should I weigh for my height and age?
What is a healthy BMI range?
The NHS defines BMI categories as follows (NHS – BMI calculator):
- Underweight: BMI less than 18.5
- Healthy weight: BMI 18.5 to 24.9
- Overweight: BMI 25 to 29.9
- Obese: BMI 30 or above
How to calculate BMI?
BMI = weight (kg) ÷ height (m)². The NHS offers a free online BMI calculator that accepts input in stones and pounds.
Weight range for a 5ft 3 woman in stones and pounds
For a 5ft 3 person (160 cm), a healthy weight for BMI 18.5–24.9 falls between approximately 49 kg (7 st 10 lb) and 63 kg (10 st 0 lb). This range comes from NHS Scotland’s conversion chart (Healthy Weight Grampian NHS PDF Chart). Age is not a direct factor in BMI, but muscle mass changes with age can shift the healthy range.
BMI is a population-level screening tool, not a diagnosis. A muscular person may have a high BMI but low body fat; an older adult may have a normal BMI with low muscle mass.
Confirmed vs. unclear
Confirmed facts
- 1 stone = 14 pounds exactly (York St John University)
- 1 stone = 6.35029318 kg (University of Manchester)
- 1 pound = 0.453592 kg (Community Pharmacy Scotland NHS Chart)
- NHS weight charts exist and are used in clinics across the UK (UHSussex NHS Trust)
What’s unclear
- Ideal weight for a given height and age varies individually; BMI is a guide, not a diagnostic tool.
- Whether stone will be replaced by kg in UK healthcare remains debated.
Expert perspectives
“A healthy BMI for most adults is between 18.5 and 24.9.”
NHS – BMI calculator (UK health authority)
“The stone is a unit of mass equal to 14 pounds avoirdupois, used in the UK and Ireland for body weight.”
Wikipedia – Stone (unit) (encyclopaedic reference)
For UK adults tracking their weight, the conclusion is straightforward: use NHS-backed conversion tables to get accurate stones and pounds, then cross-check with BMI guidance. The alternative — relying on approximate mental maths — risks misinterpreting healthy weight ranges.
For a worked example, see our conversion of 57 kg to stone and pounds using the same NHS chart.
Frequently asked questions
How many stones is 100 kg?
100 kg equals approximately 15 stone 10.5 pounds (15.75 stone).
What is the difference between UK stone and US stone?
There is no difference — the stone is defined the same way in both countries (14 lb), but the US rarely uses it for body weight.
Why is stone still used in the UK?
Tradition and habit. Medical scales and gym equipment in the UK are calibrated in stones and pounds because patients and staff are familiar with the units.
Is stone still used for body weight?
Yes, it is the standard unit for body weight in UK GP surgeries, hospitals, and fitness centres.
How to convert stone to pounds?
Multiply the stone number by 14. For example, 10 stone = 140 pounds.
How many kilograms is 12 stone?
12 stone = 12 × 6.35029318 = 76.2 kg.
What is 10 stone in kg?
10 stone = 63.5 kg.