{ } How to use

Type the mass you want to convert.
Pick the unit you have in From and the unit you want in To — the result updates as you change them.

{ } How it works

Mass / Weight Converter works on the text you provide. Adjust the options, then select Process ▸ and it runs entirely in your browser — nothing is uploaded to a server — then shows the result in the Output panel.

Inputs

Amount — paste or type your input in the left panel (use Sample for an example)
From — choose one — Milligrams (mg), Grams (g), Kilograms (kg), Metric tons (t), Ounces (oz), Pounds (lb), Stone (st) (default: Kilograms (kg))
To — choose one — Milligrams (mg), Grams (g), Kilograms (kg), Metric tons (t), Ounces (oz), Pounds (lb), Stone (st) (default: Pounds (lb))

Output

TXT text — copy or download it from the Output panel.

{ } Common uses

Convert a figure from a recipe, a datasheet or a spec written in other units.
Check a supplier or paper that quotes the metric value against the imperial one.
Settle a unit mismatch between two systems before the number goes into code.

{ } Limitations

Enter a plain number: a value with the unit typed into it, a thousands separator or a fraction is not parsed.
Results are rounded to 12 significant digits, which is past the precision of any measurement but not exact for every ratio.
This converts mass, not force: a kilogram is a mass and a pound here is the pound-mass, not pound-force. Stone is the imperial 14-pound stone.

{ } FAQ

Is my data uploaded to a server?

No. Everything runs locally in your browser — your files never leave your device.

Can I process more than one file at once?

This tool works on one input at a time.

Is this tool free?

Yes — it’s completely free and needs no sign-up.

Is the conversion exact?

The factors are the exact defined ones where a definition exists — a pound is 0.45359237 kg by definition, an inch is 25.4 mm. What rounds is the arithmetic, at the twelfth significant digit.