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Weight Converter

Convert between metric, imperial and other weight units.

Choose the right conversion tool

The converters share a common interface, but each uses different units and data.

The weight converter changes a value between 12 supported mass units using fixed factors relative to the kilogram. It covers metric units as well as ounces, pounds, stone, US and UK tons, carats and grains.

How it works

Enter a value, select the source mass unit and target unit, then choose Convert. Internally the calculator multiplies the value by the source unit's kilogram factor and divides by the target unit's kilogram factor. The swap control reverses the two units.

The formula

Converted value = entered value × source-unit kilogram factor ÷ target-unit kilogram factor

Supported units are microgram, milligram, gram, kilogram, metric ton, ounce, pound, stone, US ton, UK ton, carat and grain. The implemented factors include 1 lb = 0.45359237 kg, 1 oz = 0.028349523125 kg, 1 US ton = 907.18474 kg, 1 UK ton = 1016.0469088 kg and 1 carat = 0.0002 kg.

Worked example

One kilogram converts to approximately 2.20462262185 pounds. One ounce converts to exactly 28.349523125 grams using the implemented factors, and one stone converts to 14 pounds.

The calculator converts numerical mass units using fixed factors. It does not account for scale calibration, measurement uncertainty or local trade rules governing physical weighing.

Frequently asked questions

Is a metric ton the same as a US or UK ton?

No. A metric ton is 1,000 kg, while a US ton is 907.18474 kg and a UK ton is 1,016.0469088 kg in the calculator.

Can the converter handle jewelry units?

Yes. Carat and grain are included. One carat is represented as 0.2 gram.

Why is this called a weight converter if the units are mass units?

In everyday usage these units are commonly described as weight units. The mathematical conversion implemented here converts fixed mass quantities and does not calculate gravitational force.

Last content reviewAugust 8, 2026
Editorial reviewHe-Sab Editorial Review

Sources and references

These sources are used to verify terminology, formulas, and information related to this calculator.