Convert milligrams, grams, kilograms, metric tonnes, ounces and pounds — instant results, free, no sign-up.
How weight conversion works
Metric mass units are decimal multiples of the kilogram (the metric tonne is 1,000 kg), while US customary weight uses the pound of 16 ounces. All factors below are exact against the kilogram, so conversions are reliable for cooking, shipping and science homework alike.
| Unit | Equals |
|---|
| 1 Milligram (mg) | 0.000001 kg |
| 1 Gram (g) | 0.001 kg |
| 1 Kilogram (kg) | base unit |
| 1 Metric ton (t) | 1000 kg |
| 1 Ounce (oz) | 0.0283495 kg |
| 1 Pound (lb) | 0.453592 kg |
All weight conversions
Every weight pair has its own quick-reference page with a conversion table:
Back to the full unit converter for all seven categories.
Common mistakes to avoid
- Mixing up ounces. The Weight category uses the ounce (oz), a unit of mass (28.3495 g). The Volume category uses the US fluid ounce (fl oz), a unit of capacity (29.5735 mL). One fluid ounce of water weighs about 1.04 oz, not exactly 1 oz, so always confirm which category you are in before converting.
- Confusing bits and bytes. File sizes are measured in bytes, network speeds in bits. In Data storage, 1 byte equals 8 bits, so a 100 Mbit per second connection transfers at most 12.5 megabytes per second.
- Assuming imperial gallons. Every volume unit here is US customary: 1 US gallon is 3.785 liters. A UK imperial gallon is 4.546 liters, roughly 20 percent larger, so results will not match UK fuel economy figures.
A quick accuracy check
Want to sanity-check any converter? Convert -40 from Celsius to Fahrenheit: the result must be exactly -40, the only temperature where the two scales meet. Then convert 0 Kelvin to Celsius: you should get -273.15, absolute zero. A converter that handles both edge cases correctly has sound temperature formulas, and this one does.
Frequently asked questions
How many pounds are in a kilogram?
One kilogram is approximately 2.2046 pounds. In the other direction, one pound is exactly 0.45359237 kilograms by international agreement.
Is an ounce a unit of weight or volume?
Both exist. This category uses the avoirdupois ounce (28.3495 g), a unit of mass. Fluid ounces measure volume and live in the Volume category — one fluid ounce of water weighs about 1.04 oz, not exactly 1 oz.