Stones, Pounds, and Kilograms: A Complete Weight Conversion Guide

Updated: February 2026 6 min read Practical Guide

Body weight is one of those measurements where three different systems collide. In the United States, people talk in pounds. In the United Kingdom and Ireland, stones and pounds are the norm. Everywhere else, kilograms rule. If you have ever wondered how to compare a weight given in stones with one in kilograms, or why your UK friend says "11 stone" instead of pounds, this guide explains the three systems, gives you exact conversion formulas, and shows when each unit is used.

The Three Weight Systems Explained

Pounds (lb or lbs) are the standard unit for body weight in the United States. When Americans step on a scale, the number is in pounds. One pound is roughly 0.45 kilograms. Pounds are also used in the UK for smaller amounts and in contexts like boxing or wrestling.

Stones (st) are used mainly in the UK and Ireland for personal weight. One stone equals exactly 14 pounds. So when someone says they weigh "10 stone 5," they mean 10 stone plus 5 pounds, or 145 pounds in total. Stones are rarely used in the US or in most metric countries.

Kilograms (kg) are the metric unit of mass and the global standard. Most of the world, including doctors and scientists, uses kilograms. One kilogram is about 2.2 pounds, and one stone is about 6.35 kilograms.

Conversion Formulas

Use these formulas for precise conversions:

Stones to kg: Multiply stones by 6.35. Example: 10 stone = 10 x 6.35 = 63.5 kg.
Stones to pounds: Multiply stones by 14. Example: 10 stone = 140 lb.
Pounds to kg: Multiply pounds by 0.4536. Example: 154 lb = 154 x 0.4536 = 69.85 kg.
Kg to stones: Divide kg by 6.35. Example: 75 kg = 75 / 6.35 = 11.81 stone (11 stone 11 lb).

Weight Conversion Chart

Use this table to quickly look up body weight from 8 stone to 20 stone in pounds and kilograms.

Stone	Pounds (lb)	Kilograms (kg)
8 st	112 lb	50.8 kg
9 st	126 lb	57.2 kg
10 st	140 lb	63.5 kg
11 st	154 lb	69.9 kg
12 st	168 lb	76.2 kg
13 st	182 lb	82.6 kg
14 st	196 lb	88.9 kg
15 st	210 lb	95.3 kg
16 st	224 lb	101.6 kg
17 st	238 lb	108.0 kg
18 st	252 lb	114.3 kg
19 st	266 lb	120.7 kg
20 st	280 lb	127.0 kg

Why Does the UK Use Stones?

The stone has been used in the British Isles for centuries. Historically, it was a practical unit for weighing goods and people. When the UK moved toward metric in the late 20th century, kilograms became the official unit for trade and health, but stones stayed in everyday speech. Today, many Brits still think of their weight in stones and pounds out of habit. It is cultural, not legal: official records and medicine use kilograms.

When You Need Each Unit

Knowing which unit to use saves confusion:

Medical and clinical: Kilograms. Doctors, nurses, and drug dosing use kg. BMI is calculated from height in meters and weight in kg.
Fitness apps and scales: Depends on region. US apps often use pounds; UK ones may offer stones and pounds; many global apps use kg. Check your app settings.
Airline baggage: Kilograms. Most airlines worldwide state limits in kg (e.g. 23 kg per bag).
Boxing and wrestling: Pounds. Weight classes are in lb (e.g. heavyweight, welterweight).
Everyday UK conversation: Stones and pounds. "What do you weigh?" is usually answered in stone and lb.

Common Body Weight References

Here are some typical weights in all three units for quick reference.

Stones & lb	Pounds only	Kilograms
8 st 0 lb	112 lb	50.8 kg
10 st 0 lb	140 lb	63.5 kg
11 st 0 lb	154 lb	69.9 kg
12 st 7 lb	175 lb	79.4 kg
14 st 0 lb	196 lb	88.9 kg
15 st 10 lb	220 lb	99.8 kg

Quick Conversion Tricks

For a rough stones to kg estimate, multiply stones by 6. For kg to stones, divide kg by 6. To get pounds from kg quickly, double the kg and add 10 percent (e.g. 70 kg is about 154 lb). For exact values, use the formulas above or our kg to lbs and lbs to kg tools.

Frequently Asked Questions

How many kg is 1 stone?

One stone equals 6.35 kilograms. To convert stones to kg, multiply by 6.35.

How many pounds is 1 stone?

One stone equals exactly 14 pounds.

Why does the UK weigh people in stones?

The stone has been used in the British Isles for centuries. While the UK officially adopted the metric system, stones remain the cultural norm for discussing body weight in casual conversation.

How do I convert 75 kg to stones and pounds?

Divide 75 by 6.35 to get 11.81 stones, which is 11 stone 11.3 pounds (11 st 11 lb).

Do doctors in the UK use stones or kilograms?

UK medical professionals use kilograms for clinical purposes, including prescribing medication and calculating BMI. Stones are used informally by patients in conversation.