Blog
Unit converters

Mass unit converter

Enter a value, choose a source and target unit, and the converter recalculates mass between any pair of eight units: milligrams, grams, kilograms, tonnes, pounds, ounces, stones and carats.

Your data never leaves this device

Result

Result

This page has no server side at all. The table you paste is parsed by JavaScript inside your own browser, the chart is drawn on a canvas element on your machine, and the export file is assembled locally. Nothing is uploaded, stored or written to any log. You can disconnect from the network after the page has loaded and everything will still work — which is the simplest way to verify the claim yourself.

Facts and limits of this method

Base unit Kilogram — all other units convert through it
1 pound 0.45359237 kg (exact international definition)
1 ounce 28.349523125 g (1/16 pound)
1 stone 6.35029318 kg (14 pounds, British unit)
1 carat 0.2 g (200 mg, jewelry and gemology unit)
Total units 8 — mg, g, kg, t, lb, oz, stone, carat

When it misleads you

How it is calculated

Each of the eight units has a preset conversion factor to kilograms — for example, 1 pound = 0.45359237 kg, 1 carat = 0.0002 kg.

The entered value is multiplied by the factor of the selected "from" unit, giving mass in kilograms.

The mass in kilograms is divided by the factor of the "to" unit, giving the result in the target unit.

The result is rounded to the chosen number of decimal places and updates instantly whenever the value, units or precision change.

Questions and answers

Which tonne is used — metric or US?

The metric tonne (1000 kg). The US short ton (907.18 kg) and UK long ton (1016.05 kg) aren't supported here — their factors differ from the metric one.

Are carats about diamond weight?

Yes, the metric carat (0.2 g) is the standard unit of mass for gemstones and pearls.

Can I convert pounds to stones?

Yes, the converter works for any pair among the eight units, including conversions within the British system of units.

Is my data sent anywhere?

No, the whole calculation runs in your browser.

Related tools

All tools