kg to lbs, Stone and Ounces: Weight Conversions That Stick

Three weight systems share the world: kilograms almost everywhere, pounds in the US, and stone for body weight in the UK and Ireland. They are all locked together by one exact definition — a pound is 0.45359237 kg.

ConversionBy Jun 27, 20265 min read
kg to lbs, Stone and Ounces: Weight Conversions That Stick — ListCalc

The three constants

1 kg = 2.20462 lb  (1 lb = 0.45359237 kg, exact)
1 stone = 14 lb = 6.35029 kg
1 oz = 28.3495 g

The pound’s definition is exact by international agreement, which makes every factor here a derived, fixed number — not a rounded convention that varies by country.

Body weight: kg ↔ lbs

kglbskglbs
50110.280176.4
55121.385187.4
60132.390198.4
65143.395209.4
70154.3100220.5
75165.3110242.5

The fast mental version: double the kilograms, then add 10%. 70 kg → 140 + 14 = 154 lb (exact: 154.3). Going the other way, take 10% off the pounds and halve: 180 lb → 162 ÷ 2 = 81 kg (exact: 81.6). The kg to lbs converter gives the precise figure both ways.

Stone: how the UK weighs people

A stone is exactly 14 pounds, and UK body weight is spoken as stone-and-pounds: “11 stone 4” means 11 × 14 + 4 = 158 lb. The leftover pounds are pounds, not decimals — 11.5 stone is 11 stone 7, not 11 stone 5.

StonePoundskg
811250.8
912657.2
1014063.5
1115469.9
1216876.2
1318282.6
1419688.9
1521095.3

A handy coincidence: 10 stone, 140 lb and 63.5 kg all name the same weight, and 70 kg sits almost exactly at 11 stone (11 st 0.3 lb). The stone to pounds converter handles the stone-and-pounds format directly.

Grams to ounces in the kitchen

Recipes cross the Atlantic constantly, and this is the conversion that decides whether they survive the trip. An avoirdupois ounce is 28.3495 g:

GramsOuncesWorth knowing
28.351.001 oz exactly
501.76
1003.53
1133.991 stick of butter / quarter pound
2508.82
45416.011 lb
50017.64

Two warnings. First, the rough “30 g per ounce” shortcut runs 5.8% heavy — fine for vegetables, risky for baking. Second, don’t confuse weight ounces with fluid ounces, which measure volume; 8 fl oz of flour does not weigh 8 oz. For dry ingredients by weight, the grams to ounces converter is the one you want.

Run your own numbers

kg to lbs Stone to pounds Grams to ounces

FAQ

How many pounds is 1 kg?
1 kilogram is 2.20462 pounds. The definition actually runs the other way: a pound is exactly 0.45359237 kg by international agreement, and 1 ÷ 0.45359237 = 2.20462.
What is the fastest way to convert kg to lbs in your head?
Double the kilograms and add 10%. For 70 kg: doubled is 140, plus 14 is 154 lb — the exact answer is 154.3. The trick works because 2.2 = 2 × 1.1.
How many pounds is a stone?
Exactly 14 pounds. UK body weight is spoken as stone and pounds — '12 stone 6' is 12 × 14 + 6 = 174 lb, or about 78.9 kg.
How many grams are in an ounce?
28.3495 grams. The common '30 grams' shortcut overshoots by nearly 6%, which matters in baking — 8 oz of flour is 227 g, not 240 g.
Is a fluid ounce the same as an ounce?
No. An ounce measures weight (28.35 g); a fluid ounce measures volume (29.57 mL). They only coincide for water-like liquids — a fluid ounce of flour or oil does not weigh one ounce.

Sources

Primary references used for the figures and rules on this page.

  1. Definition of the avoirdupois pound (0.45359237 kg) — NIST
  2. Units of weight and measure — NIST Handbook 44