Free Weight & Mass Converter that works offline
Convert common metric and imperial mass units as you type. Standard exact factors are used for international avoirdupois pounds and ounces.
What this weight & mass converter does
Every unit is normalized to grams before conversion to the target. Everyday language often says weight, while the numerical units listed here describe mass; local gravity is not part of the calculation.
How to use the Weight & Mass Converter
- Enter or paste a numeric mass and source and target units into the tool.
- Adjust the available options so they match the format and result you need.
- Choose Convert and review the equivalent value using grams as the shared base before using it.
- Copy or download the result, then clear the page if the input was sensitive.
Common uses
- Converting recipes and package labels
- Comparing kilograms and pounds
- Changing stone to metric units
- Checking shipping and inventory examples
Private processing and offline access
This tool does not submit your input to a conversion server. Processing takes place inside the browser using local JavaScript and standard Web APIs. After the PWA has been installed or cached, the page and its core features remain available without an internet connection. Closing or clearing the page removes unsaved input; the tool does not create an account or cloud history.
Tips for accurate results
- Confirm that a source uses avoirdupois rather than troy ounces.
- A metric tonne equals 1,000 kilograms.
- Legal and scientific work may require documented rounding rules.
Frequently asked questions
Does this tool upload my data?
No. Weight & Mass Converter processes its input in the current browser and does not submit it to a conversion API.
What input does the Weight & Mass Converter accept?
Milligrams, grams, kilograms, avoirdupois ounces and pounds, stone and metric tonnes are included.
Can I use this tool offline?
Yes. Once the Offline Tools PWA has cached the page, the core feature works without an internet connection.