What is the Weight (Mass) Conversion Calculator?
This tool converts a measurement of mass from one unit to another. It supports the most common metric and imperial units: kilograms (kg), grams (g), milligrams (mg), pounds (lb), ounces (oz), and metric tons (t). It works for any country since these unit definitions are international standards.
How to use it
Enter the value you want to convert, choose the unit it is currently in under From, then pick the unit you want the answer in under To. The calculator shows the converted amount and also displays the equivalent in grams as a reference.
The formula explained
Every unit is expressed relative to a single base — the gram. Each unit has a factor equal to how many grams it contains: 1 kg = 1000 g, 1 mg = 0.001 g, 1 lb = 453.59237 g, 1 oz = 28.349523125 g, and 1 metric ton = 1,000,000 g. To convert, the value is first turned into grams (value × fromFactor), then divided by the target unit's factor (grams ÷ toFactor). This two-step base conversion lets any unit convert to any other unit reliably.
$$\text{result} = \dfrac{\text{value} \times \text{fromFactor}}{\text{toFactor}}$$
$$\text{grams} = \text{value} \times \text{fromFactor}$$
$$\text{result} = \dfrac{\text{grams}}{\text{toFactor}}$$
Worked example
Convert 5 kilograms to pounds. First to grams: \(5 \times 1000 = 5000\) g. Then to pounds: \(5000 \div 453.59237 = 11.0231\) lb. So \(5\ \text{kg} \approx 11.02\ \text{lb}\).
FAQ
Is a metric ton the same as a US ton? No. This calculator uses the metric ton (1000 kg = 1,000,000 g), not the US short ton (907.18 kg) or UK long ton.
Are pounds and ounces exact? Yes, they use the international avoirdupois definitions: 1 lb = 453.59237 g exactly, and 1 oz = 28.349523125 g exactly.
What's the difference between weight and mass? Strictly, mass is the amount of matter and weight is a force, but in everyday use these units (kg, lb, etc.) describe mass, which is what this tool converts.
