How to Convert kg to lb by Hand (With the Exact Formula)

Published 2026-10-01

Kilograms to pounds is one of the most common conversions people need, whether it is body weight, luggage limits, or a recipe from another country. The good news is that you only need one number to do it by hand: 1 kilogram is 2.20462 pounds. This guide shows you where that number comes from, how to do the math on paper, and a mental shortcut that gets you within a percent or two in seconds.

Why the factor is 2.20462

The conversion factor is not an approximation someone measured once. It falls out of a definition. Since 1959, the international pound has been defined as exactly 0.45359237 kilograms. That is a fixed, legal definition, not a measurement with error bars.

So if 1 pound is 0.45359237 kilograms, then 1 kilogram is 1 divided by 0.45359237 pounds, which works out to 2.2046226218… pounds. The digits keep going, but 2.20462 is plenty for everyday use. Rounded to fewer places, you will also see 2.2, which is fine for rough estimates but drifts noticeably at larger weights.

To convert in the other direction, from pounds to kilograms, multiply by 0.45359237 instead.

The basic method

To convert kilograms to pounds:

Write down the weight in kilograms.
Multiply it by 2.20462 (or by 2.2046226218 if you want the full precision).
Round the result to whatever precision makes sense for the situation.

That is the whole method. One multiplication, no tricks.

Worked examples

Example 1: 5 kg to lb. Multiply 5 by 2.2046226218 to get 11.023113109, so 5 kg is about 11.02 lb. A 5 kg bag of rice weighs just over 11 pounds.

Example 2: 70 kg to lb. Multiply 70 by 2.2046226218 to get 154.323583526, so 70 kg is about 154.32 lb. This is a common adult body weight, and you will often see it rounded to 154 lb.

Example 3: 0.5 kg to lb. Multiply 0.5 by 2.2046226218 to get 1.1023113109, so half a kilogram is about 1.10 lb.

Example 4: going the other way, 150 lb to kg. Multiply 150 by 0.45359237 to get 68.0388555, so 150 lb is about 68.04 kg.

The mental shortcut: double it and add 10 percent

If you do not have a calculator handy, there is a well known shortcut: double the kilograms, then add 10 percent of that doubled value. This works because 2.2 is very close to 2.20462.

Here is how it plays out with the examples above:

5 kg: double is 10, plus 10 percent (1) gives 11 lb. The exact answer is 11.02 lb.
70 kg: double is 140, plus 10 percent (14) gives 154 lb. The exact answer is 154.32 lb.

The shortcut undershoots by about 0.2 percent, which is invisible for luggage estimates and casual conversation. For anything medical, legal, or commercial, use the exact factor or a converter.

Common mistakes to avoid

Mixing up the direction. Multiplying pounds by 2.2 makes the number bigger, which is wrong: pounds to kilograms should make the number smaller. If your result goes the wrong way, you used the wrong factor.
Using 2 instead of 2.2. “Two pounds per kilo” is a 10 percent error, and it compounds at higher weights.
Confusing mass and force. The kilogram is a unit of mass and the pound is used for both mass and force depending on context, but for body weight and groceries the simple factor above is all you need.

When to skip the math entirely

Doing it by hand is a good skill, but if you are converting a list of values or need exact decimals, the converter on our homepage does it instantly in your browser. Type the number, get the answer, and move on. For more background on why these two systems coexist, see our guide to metric versus imperial history.