AI Weight Loss Simulator Logo
FREE · INSTANT

Pounds to Kilograms

Convert pounds to kilograms and back, instantly. Type in either box and the other updates — plus stones, a quick mental shortcut, and a reference table of the weights people look up most.

1 lb = 0.45359237 kg · 1 kg = 2.2046226218 lb · Works both ways

In kilograms

68.04 kg

In pounds

150.00 lb

In stones

10 st 10.0 lb

Still standard for body weight in the UK and Ireland.

The mental shortcut

Halve the pounds, then take off about 10 percent. 150 lb → 75 → minus 10 percent → about 67.5 kg. The exact answer is 68.0 kg, so the trick is within a pound at normal body weights.

Pounds to kilograms table

The conversions people look up most often, rounded to one decimal place.

PoundsKilograms
100 lb45.4 kg
110 lb49.9 kg
120 lb54.4 kg
125 lb56.7 kg
130 lb59.0 kg
140 lb63.5 kg
150 lb68.0 kg
160 lb72.6 kg
170 lb77.1 kg
175 lb79.4 kg
180 lb81.6 kg
190 lb86.2 kg
200 lb90.7 kg
210 lb95.3 kg
220 lb99.8 kg
230 lb104.3 kg
250 lb113.4 kg
275 lb124.7 kg
300 lb136.1 kg
KilogramsPounds
45 kg99.2 lb
50 kg110.2 lb
55 kg121.3 lb
60 kg132.3 lb
65 kg143.3 lb
70 kg154.3 lb
75 kg165.3 lb
80 kg176.4 lb
85 kg187.4 lb
90 kg198.4 lb
95 kg209.4 lb
100 kg220.5 lb
110 kg242.5 lb
120 kg264.6 lb

Where the number comes from

Since the International Yard and Pound Agreement of 1959, one avoirdupois pound has been defined as exactly 0.45359237 kilograms. The conversion is not measured or approximated — the pound is legally defined in terms of the kilogram, which is why the factor runs to eight decimal places and never changes. Going the other way, one kilogram is 2.2046 pounds, a repeating decimal that gets rounded to 2.2 in everyday use.

For body weight this precision rarely matters — the difference between 2.2 and 2.2046 is under half a pound at 200 lb. It matters more for medication dosing and lab work, which is why clinical settings work in kilograms almost everywhere, including in countries that otherwise use pounds.

Pounds and Kilograms FAQ

Conversion factors, stones, and where each unit is used.

How do you convert pounds to kilograms?

Divide the number of pounds by 2.2046226218, or multiply by 0.45359237. For a quick mental estimate, halve the pounds and then subtract about 10 percent — 150 lb halves to 75, minus 10 percent gives 67.5 kg, and the exact answer is 68.0 kg.

How many kg is 1 pound?

One pound is exactly 0.45359237 kilograms. That figure is not an approximation — the international avoirdupois pound has been legally defined against the kilogram at that exact value since 1959.

How many pounds is 1 kg?

One kilogram is about 2.2046226218 pounds. The rough version most people use is 2.2, which is accurate enough for everyday body weight — it drifts by less than half a pound at 200 lb.

Why do some countries use pounds and others kilograms?

The kilogram is the SI base unit and is standard almost everywhere. The pound survives in everyday use mainly in the United States, and alongside stones in the United Kingdom and Ireland for body weight. Most medical and scientific settings use kilograms regardless of country.

What is a stone in pounds and kilograms?

One stone is 14 pounds, or about 6.35 kilograms. It is still commonly used for body weight in the UK and Ireland — someone who says they weigh 11 stone 4 means 158 pounds, or about 71.7 kg.

Is this converter free?

Yes. It runs entirely in your browser, needs no account, and uses no credits. Credits on this site only apply to the AI photo simulator.

Now that you have the number, put it to work: check your BMI, find your daily calories, or get a date for your goal weight.

See the weight, in any unit

Pounds or kilograms, the picture is the same. Upload one photo and preview a realistic before-and-after at your target weight. First simulation is free.

Try the Weight Loss SimulatorSee Pricing