Unit converter

Pounds to Kilograms (lbs to kg)

To convert pounds to kilograms, multiply by 0.45359237, the exact legal definition of the international pound. 150 lb is 68.04 kg and 200 lb is 90.72 kg. The converter works in both directions.

Convert lbs to kg

lbs to kg

150 lb = 68.0389 kg

1 lb = 0.453592 kg · 1 kg = 2.20462 lb

Show the math

kg = lb × 0.45359237

Uses exact legal definitions; results are rounded to 6 significant figures for display.

How to convert lbs to kg

kg = lb × 0.45359237

One pound is exactly 0.45359237 kilograms, so multiply by 0.45359237.

Worked example: converting 150 lb:

kg = lb × 0.45359237
150 lb × 0.45359237 = 68.0389 kg

Lbs to kg conversion table

Common values, each computed with the exact formula and rounded to 6 significant figures.

Pounds (lb) to Kilograms (kg)
Pounds (lb)	Kilograms (kg)
1 lb	0.453592 kg
2 lb	0.907185 kg
5 lb	2.26796 kg
10 lb	4.53592 kg
15 lb	6.80389 kg
20 lb	9.07185 kg
25 lb	11.3398 kg
30 lb	13.6078 kg
35 lb	15.8757 kg
40 lb	18.1437 kg
45 lb	20.4117 kg
50 lb	22.6796 kg
60 lb	27.2155 kg
70 lb	31.7515 kg
80 lb	36.2874 kg
90 lb	40.8233 kg
100 lb	45.3592 kg
110 lb	49.8952 kg
120 lb	54.4311 kg
130 lb	58.967 kg
140 lb	63.5029 kg
150 lb	68.0389 kg
160 lb	72.5748 kg
170 lb	77.1107 kg
180 lb	81.6466 kg
190 lb	86.1826 kg
200 lb	90.7185 kg
220 lb	99.7903 kg
250 lb	113.398 kg
300 lb	136.078 kg

Quick reference: everyday pounds in kilograms

One pound
1 lb = 0.453592 kg
US barbell plate
45 lb = 20.4117 kg
Common checked-bag limit on US airlines
50 lb = 22.6796 kg
Round 100 lb
100 lb = 45.3592 kg
Two-plate barbell (bar + two 45s)
135 lb = 61.235 kg
Round 200 lb
200 lb = 90.7185 kg

Why health tools ask for kilograms

Clinical formulas, drug labels and nutrition guidelines are almost always written in kilograms. Pediatric doses are usually given in milligrams per kilogram, so a child's weight in pounds has to be converted precisely before any dose is worked out. That's a job for a pharmacist or prescriber, not a rough rule of thumb.

For fitness math the stakes are lower but the unit still matters. Protein goals of 1.2–2.0 g per kg sound smaller than they are if you read them as grams per pound, which would be 2.2 times more. Our calories calculator and BMR calculator take weight in pounds and convert to kilograms internally, so you don't have to.

Gym plates, freight and shipping labels

US gyms use 45 lb plates, which are 20.41 kg, a little heavier than the 20 kg metric plates used in competition. A barbell loaded with two 45s on a 45 lb bar totals 135 lb (61.2 kg). If you train in both systems, work out the total once in kilograms rather than converting plate by plate, so rounding errors don't add up.

International couriers price by kilogram, and many round up to the next half-kilo. A 10 lb parcel is 4.54 kg, so it may be billed at 5 kg. If a box is light but bulky, carriers may charge by dimensional weight instead.

Frequently asked questions

What's an easy mental shortcut for lbs to kg?

Halve the pounds, then subtract 10% of that half. For 150 lb: half is 75, minus 7.5 gives 67.5 kg, against an exact 68.04 kg. The shortcut multiplies by 0.45 instead of 0.4536, so it always runs about 0.8% low. That's fine for conversation, but not for dosing or competition weigh-ins.

Why is pounds abbreviated 'lb'?

The abbreviation comes from the Latin 'libra', a Roman unit of weight, which is also where the £ sign for the British pound sterling comes from. 'Lb' and 'lbs' mean the same thing. Style guides usually prefer 'lb' for both singular and plural, but 'lbs' is common on product labels and in search queries.

Is a troy pound the same as a regular pound?

No. Precious metals use the troy system, where a troy pound is 12 troy ounces, or 373.24 g. That's about 18% lighter than the everyday avoirdupois pound of 453.59 g. Gold and silver are almost always quoted per troy ounce rather than per troy pound, and this converter uses the ordinary avoirdupois pound.