Pounds to Kilograms Converter

The converter above is already set to pounds and kilograms, so you only need to enter your number. The result updates as you type, and nothing is sent anywhere.

1. Type your value in the Value box, for example 150. Decimals and negative numbers are accepted.
2. Check that From shows pounds and To shows kilograms. Both menus can be changed if you need a different pair.
3. Read the answer in the large result box. The note under it shows the exact factor used for one pound.
4. Press Copy result to put the answer on your clipboard, or Swap units to convert in the opposite direction.
5. Look at In every unit on the right to see the same amount in all the other weight units.

One pound is about 0.453592 kilograms, so the formula is kilograms = pounds x 0.453592. Going the other way, one kilogram is about 2.20462 pounds. The pound is defined as exactly 0.45359237 kilograms, and the abbreviation lb comes from the Latin word libra. The kilogram is the base unit of mass in the metric system and is used for body weight in most countries.

Worked examples with the same factor:

• 150 pounds: 150 x 0.453592 = 68.0389 kilograms
• 375 pounds: 375 x 0.453592 = 170.097 kilograms
• 1,500 pounds: 1,500 x 0.453592 = 680.389 kilograms

Halve it and take off 10 percent of that: 150 lbs is 75 minus 7.5, which is 67.5 kg, exactly 68.04.

To check the converter by hand, take 375 pounds and apply the rule once: the result should be 170.097 kilograms. If you go back again with the reverse factor 2.20462 you land on 375 pounds, which confirms that the two directions agree. Rounding the factor to fewer digits for mental math gives a result that is close but not identical, so use the tool when the last digits matter.

These reference values come from the same factor the converter uses, so they match what you see above. Use the table for common amounts, and the converter for anything else.

Pounds, ounces and stone belong to the avoirdupois system, while grams and kilograms belong to the metric system. Since 1959 the pound has been defined as exactly 0.45359237 kilograms in the United States and the Commonwealth, so conversions are exact rather than approximate. Shops, gyms, airlines and doctors each pick one system, which is why people switch between them so often.

Use the table as a sanity check rather than a substitute for the converter. The result must scale with the input: double the weight and the converted figure doubles. For anything that matters, such as a medicine dose or a shipping charge, read the unit printed on the scale or label first, because the same number means very different things in each system.

Fitness trackers, baby weights, luggage limits and shipping labels use pounds in the United States and kilograms nearly everywhere else.

Weight and mass are used interchangeably in everyday speech, and these units measure mass. The pound-mass and kilogram conversion is exact, but a kitchen scale can only show the precision it was built with, so do not trust more decimals than the scale gives. Also keep ounces of weight apart from fluid ounces of volume.

Related pages: Kilograms to Pounds Converter for the reverse direction, and the stone to kilograms and kilograms to grams pages. For other weight units use the weight converter.

The page keeps no history, so each visit starts again from the defaults, 150 pounds. Your numbers are processed by JavaScript in your own browser and are never sent to a server, which makes the converter safe for private figures such as medical, financial or work measurements.