Does this unit converter need an internet connection?

No. Every conversion factor is built into the page, so it keeps working offline once loaded and never sends your numbers anywhere.

Can I convert a whole list of numbers at once?

Yes — switch to Advanced mode and paste one value per line into the batch box to get every result converted in one go, downloadable as CSV.

How accurate are the conversions?

Factors use standard international definitions (e.g. exact SI values, the international foot and pound). You control the displayed precision with decimal places or significant figures.

Why does temperature behave differently from other units?

Temperature scales use an offset as well as a scale factor (Celsius to Fahrenheit is ×9/5 + 32), so it is handled with its own formula rather than a simple multiplier.

Can I restrict the list to only metric or only imperial units?

Yes, use the unit system filter in Advanced mode to show only Metric, Imperial, US customary or UK units in the pickers.

ToolMano

Unit converter

Convert length, weight, temperature and 15 more unit categories.

No uploadNo signupWorks offline

Unit	Value
Millimetre (mm)	1,000.0000
Centimetre (cm)	100.0000
Metre (m)	1.0000
Kilometre (km)	0.0010
Inch (in)	39.3701
Foot (ft)	3.2808
Yard (yd)	1.0936
Mile (mi)	0.0006
Nautical mile	0.0005

About unit converter

Unit converter switches instantly between metric, imperial and US customary units across twenty categories: length, weight, temperature, area, volume, speed, time, pressure, energy, power, data storage, data transfer, angle, fuel economy, frequency, force, torque, density, illuminance and cooking measures.

Type a value once and see it converted to every other unit in that category at the same time, with the formula shown so you can check the maths yourself. Batch mode converts a whole list of numbers in one pass, and everything runs locally in your browser — no external conversion API, no network round-trip.

Fine-tune precision with decimal places, significant figures, rounding mode and scientific or engineering notation, filter the unit list to just the system you use, and export any conversion table as CSV.

How to use Unit converter

1Pick a category such as Length, Weight or Temperature.
2Choose the unit you're converting from and to, and type a value.
3Read the instantly-updated result, formula and multi-unit table.
4Switch to Advanced for precision controls, batch conversion and CSV export.

What it does

20 unit categories from length to illuminance and cooking measures
Live multi-target conversion table, not just one result
Formula and step-by-step working shown for every conversion
Batch converts a whole list of values, one per line
Decimal, scientific, engineering and fraction notation
Metric / imperial / US / UK system filters
Swap direction with one click and keep a conversion history
Favourite unit pairs for quick access
CSV export of the full conversion table

Frequently asked questions

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