Pounds to Kilograms (lbs to kg) Converter
A fast, bidirectional converter for pounds, ounces, and kilograms. Enter a value in any field to see all values update instantly.
How to Convert Pounds to Kilograms
Converting pounds (lbs) to kilograms (kg) is a common conversion, especially for body weight, international travel, and science. The process is simple, whether you use the exact formula or a quick mental math trick.
The Exact Formula
By international agreement (the International Yard and Pound Agreement of 1959), one pound is defined as exactly **0.45359237 kilograms**.
To convert any value from pounds to kilograms, you simply multiply the pound value by 0.45359237.
Example: Convert 150 lbs to kg.
150 lbs × 0.45359237 = 68.03885... kg
The Mental Math Trick (How to Convert in Your Head)
For a fast, everyday estimate, the easiest way is to divide by **2.2**. A simple trick for this (as mentioned on Reddit and other forums) is to **"divide by 2, then subtract 10%".**
Example: Convert 180 lbs to kg using the trick.
- Divide by 2:
180 / 2 = 90 - Find 10% of that result:
10% of 90 = 9 - Subtract:
90 - 9 = 81 kg
This gives you a very fast and accurate estimate. The exact answer is 81.64 kg, so your mental math is less than 1% off.
How to Include Ounces (oz)
Since there are 16 ounces (oz) in 1 pound (lb), you must first convert your ounces to decimal pounds by dividing them by 16.
Example: Convert 150 lbs, 5 oz to kg.
- Convert ounces to decimal pounds:
5 oz / 16 = 0.3125 lbs - Add to the total pounds:
150 + 0.3125 = 150.3125 lbs - Convert total pounds to kg:
150.3125 × 0.45359237 = 68.179... kg
Lbs to Kg Quick Conversion Chart
| Pounds (lbs) | Kilograms (kg) |
|---|---|
| 1 lb | 0.45 kg |
| 5 lbs | 2.27 kg |
| 10 lbs | 4.54 kg |
| 50 lbs | 22.68 kg |
| 100 lbs | 45.36 kg |
| 150 lbs | 68.04 kg |
| 200 lbs | 90.72 kg |
Frequently Asked Questions (FAQ)
Is 1 kg 2 lbs or 2.2 lbs?
1 kilogram (kg) is approximately equal to **2.2 pounds (lbs)**. The exact conversion is 1 kg = 2.2046226218 lbs. Using '2' is a very rough estimate and will be inaccurate.
What is the easy trick to convert lbs to kg?
The easiest mental math trick is to divide the pounds by 2.2. You can do this quickly by **dividing by 2, and then subtracting 10% of that result.** For 200 lbs: 200 / 2 = 100. Then 100 - (10% of 100) = 90 kg. (The exact answer is 90.7 kg).