Stone, Pounds and Kilograms Explained
If you have ever heard someone in Britain or Ireland describe their weight as "eleven and a half stone" and quietly wondered what that meant in numbers anyone else would recognise, you are in good company. The stone is one of the last surviving everyday imperial units, and it sits awkwardly between pounds and kilograms. This guide explains how it works.
What is a stone?
A stone is a traditional unit of weight used in the United Kingdom, Ireland and a few Commonwealth countries. Its symbol is st, and the rule is simple: one stone equals fourteen pounds.
Despite the United Kingdom officially adopting the metric system decades ago, the stone has stubbornly held on for one purpose in particular: describing personal body weight. Step on a bathroom scale at a gym in Manchester and the display might read 12 st 4 lb. The same scale in Manchester, New Hampshire would read 172 lb instead.
This page is a unit guide. It explains how the numbers work, but does not offer health, fitness or medical advice on body weight.
Stone, pounds and kilograms at a glance
Here are the three relationships that connect every conversion in this guide. Memorise these and the rest is multiplication.
| Relationship | Exact value | Round figure |
|---|---|---|
| 1 stone | 14 pounds | 14 lb (exact) |
| 1 stone | 6.35029318 kilograms | ~6.35 kg |
| 1 kilogram | 0.157473 stone | ~0.157 st |
The stone-to-pound link has no decimals at all, which keeps mental arithmetic tidy. The stone-to-kilogram link is the messy one, with that 6.35 multiplier that does not round to anything friendly.
Converting stone to pounds
Multiply the stones by 14. That is the whole method.
| Stone | Pounds |
|---|---|
| 1 st | 14 lb |
| 5 st | 70 lb |
| 8 st | 112 lb |
| 10 st | 140 lb |
| 12 st | 168 lb |
| 14 st | 196 lb |
| 16 st | 224 lb |
| 20 st | 280 lb |
Converting pounds to stone
To go the other way, divide pounds by 14. The result splits naturally into a whole number of stones plus a remainder in pounds.
| Pounds | Stone (decimal) | Stone & pounds |
|---|---|---|
| 50 lb | 3.57 st | 3 st 8 lb |
| 100 lb | 7.14 st | 7 st 2 lb |
| 120 lb | 8.57 st | 8 st 8 lb |
| 140 lb | 10.00 st | 10 st 0 lb |
| 160 lb | 11.43 st | 11 st 6 lb |
| 180 lb | 12.86 st | 12 st 12 lb |
| 200 lb | 14.29 st | 14 st 4 lb |
| 250 lb | 17.86 st | 17 st 12 lb |
Converting stone to kilograms
Multiply the stones by 6.35029 to get kilograms. For most everyday cases, rounding to 6.35 is plenty accurate.
| Stone | Pounds | Kilograms |
|---|---|---|
| 7 st | 98 lb | 44.45 kg |
| 8 st | 112 lb | 50.80 kg |
| 9 st | 126 lb | 57.15 kg |
| 10 st | 140 lb | 63.50 kg |
| 11 st | 154 lb | 69.85 kg |
| 12 st | 168 lb | 76.20 kg |
| 13 st | 182 lb | 82.55 kg |
| 14 st | 196 lb | 88.90 kg |
| 15 st | 210 lb | 95.25 kg |
| 16 st | 224 lb | 101.60 kg |
| 17 st | 238 lb | 107.95 kg |
| 18 st | 252 lb | 114.31 kg |
| 20 st | 280 lb | 127.01 kg |
Need just one number? The stone to kilograms converter handles any value, including stone-and-pound combinations.
Converting kilograms to stone
Divide the kilograms by 6.35029, then split the answer into whole stones and leftover pounds — just like the pounds-to-stone method.
| Kilograms | Stone (decimal) | Stone & pounds |
|---|---|---|
| 40 kg | 6.30 st | 6 st 4 lb |
| 50 kg | 7.87 st | 7 st 12 lb |
| 60 kg | 9.45 st | 9 st 6 lb |
| 65 kg | 10.24 st | 10 st 3 lb |
| 70 kg | 11.02 st | 11 st 0 lb |
| 75 kg | 11.81 st | 11 st 11 lb |
| 80 kg | 12.60 st | 12 st 8 lb |
| 90 kg | 14.17 st | 14 st 2 lb |
| 100 kg | 15.75 st | 15 st 11 lb |
| 110 kg | 17.32 st | 17 st 5 lb |
| 120 kg | 18.90 st | 18 st 13 lb |
Why does Britain still use the stone?
The short answer is habit. The longer answer involves a series of half-finished metric transitions that started in the 1960s and never quite reached the bathroom scale.
Britain officially began moving to the metric system for trade in 1965. Most areas — science, medicine, food packaging, road distances on technical signs — adopted metric units smoothly over the following decades. But everyday speech kept hold of certain familiar units. Pints stuck around for beer and milk. Miles stuck around for road distances. And the stone stuck around for personal weight, even though the kilogram is on every modern set of scales sold in the country.
The result is a curious split. A British person checking their weight at home will likely think in stone. The same person at a doctor's appointment will see kilograms on the chart. Most modern scales display both, which keeps everyone happy and means nobody has to do the maths in their head.
Reading "stone and pounds" notation
Body weight in stone is almost always given in two parts: a whole number of stones, then a remainder in pounds between 0 and 13. You will see it written several ways:
- 11 st 4 lb — the most explicit form, with both unit symbols.
- 11st 4 — common shorthand on fitness apps and chat.
- 11 stone 4 — how someone would say it out loud.
- 11.29 st — decimal form, less common in everyday speech but useful on calculators.
The remainder pounds always stop at 13. Once you reach 14 lb, you have a full extra stone, so the next weight up is the next whole stone with 0 lb. This is why "11 st 14 lb" is never used — it would mean exactly 12 stone.
Quick mental shortcuts
Three approximations that get you close enough for most situations:
Stone to pounds
Multiply by 14, or — for a quick rough figure — multiply by 15 and subtract a stone's worth. For 9 st: 9 × 14 = 126, or 9 × 15 = 135 minus 9 ≈ 126. Same answer either way.
Stone to kilograms
Multiply by 6 and add about a third more. So 10 stone is roughly 60 + 3 = 63 kg (the exact value is 63.50).
Kilograms to stone
Divide by 6, then trim about 5 percent. So 70 kg is roughly 70 ÷ 6 ≈ 11.7, take a touch off → about 11 stone (the exact answer is 11.02).
Where the stone shows up beyond body weight
Although personal weight is by far the most common modern use, the stone has a longer history with other goods.
- Livestock and meat. Sheep and cattle were traditionally priced and sold by stone in British markets. Some butchers still quote certain cuts this way.
- Wool and farm produce. Historically the "stone of wool" varied by region — anywhere from 8 to 24 pounds — until standardisation pinned it to 14 lb in 1835.
- Sport. Boxers and jockeys are sometimes weighed in stone and pounds, particularly in British and Irish racing and combat sports.
- Older recipes and gardening books. Quantities of potatoes, flour or compost in pre-metric British cookbooks and almanacs are sometimes given in stones.
Related converters and reading
For an exact figure, head straight to the relevant tool:
You may also find these guides useful: our complete weight conversion chart, the kg, pounds and ounces guide, and the wider grams, ounces and pounds reference.