Weight Converter

Free weight converter: convert between kilograms, grams, milligrams, pounds, ounces, metric tons, and stones instantly.

AI-ready Use this tool with AI

This tool has a free JSON API. Copy a prompt or skill below to use it with ChatGPT, Claude, or any AI agent — no API key needed.

API docs
—
Enter a value to convert.

How weight converter works

This converter changes a weight from one unit to every other supported unit in a single step. It works by first converting the input to grams (the base unit), then dividing by the target unit factor. For example, 1 kilogram becomes 2.20462 pounds because one pound is exactly 453.592 grams.

The metric units (kilogram, gram, milligram, metric ton) are related by powers of 1000. The imperial units (pound, ounce, stone) use exact conversion factors: 1 pound = 453.592 grams, 1 ounce = 28.3495 grams, 1 stone = 6350.29 grams.

Results are rounded to six decimal places for readability. Very large or very small values are shown in scientific notation. The conversion runs live as you type, so you can experiment with values instantly.

Frequently asked questions

How do I convert kilograms to pounds?
Multiply the kilogram value by 2.20462. For example, 10 kg times 2.20462 = 22.0462 lbs. The converter does this automatically when you select kg as the source unit.
How do I convert pounds to kilograms?
Divide the pound value by 2.20462 (or multiply by 0.453592). For example, 150 lbs / 2.20462 = 68.04 kg. The converter handles this for any value.
What is a stone?
A stone is a British unit equal to 14 pounds or 6.35029 kilograms. It is commonly used in the UK and Ireland for body weight. One kilogram equals about 0.157473 stones.
Are the conversion factors exact?
The metric-to-metric conversions are exact. The imperial conversions use internationally agreed exact values: 1 pound = 453.592 grams, 1 ounce = 28.3495 grams. Results are rounded only for display.

Related tools

Converters

Length Converter

Convert meters, feet, inches, miles, km and more.

 Converters

Temperature Converter

Convert between Celsius, Fahrenheit, and Kelvin instantly.

 Converters

Data Size Converter

Convert between bytes, kilobytes, megabytes, gigabytes, and terabytes.