Unit converter
Temperature, weight, length, volume, area and speed, converted with the exact legal definitions. Type a number; the answer updates as you type.
30 cm = 11.81102362 in
Formula: in = cm ÷ 2.54
30 cm in every length unit
- millimetre
- metre
- kilometre
- inch
- foot
- yard
- mile
- nautical mile
Faster with a keyboard
- / jump to the value box
- Alt+S swap units
- Alt+F save the pair
- Alt+C copy the result
- Alt+1–6 switch measurement type
On a Mac, Alt is the Option key.
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Why the numbers are exact
Imperial and US units are not measured against metric ones; they are defined in metric. The inch is 2.54 cm by international agreement, the pound 0.453 592 37 kg, the US gallon 231 cubic inches. Read how units are defined for the full chain back to the SI.
Questions
Is this unit converter free?
Yes. There is no account, no limit and no ads in the converter. Conversions run in your browser.
How accurate are the conversions?
Every factor is an exact legal definition (NIST SP 811, the 1959 international yard and pound agreement, the UK Weights and Measures Act 1985 and the SI Brochure). Results are shown to 10 significant digits.
Does it work offline?
Yes. After your first visit the pages are cached, and you can install ConvertQuick as an app from your browser menu (or the Install button in the footer where supported).
Where are my history and saved pairs stored?
Only in this browser, in localStorage. Nothing is uploaded. You can clear them on this page or on the privacy page.
What keyboard shortcuts are there?
/ focuses the value box, Alt+S swaps units, Alt+F saves the pair, Alt+C copies the result, and Alt+1 to Alt+6 switch between measurement types.