Common Unit Conversion FAQs

Quick answers to frequent questions.

How do I convert on tounits.com?

Type a number and unit in the search box (e.g. 5 feet, 100 kg). Results appear instantly. You can also pick an input unit from the dropdown and type just a number.

Which units are supported?

We support length, mass, temperature, volume, area, time, and more—including metric, US customary, and imperial. Use the unit selector or type the unit name (e.g. “inch”, “liter”, “celsius”) after your number.

Is the conversion accurate?

We use standard conversion factors (e.g. 1 inch = 2.54 cm). Results are suitable for general use. For critical applications (engineering, medicine, legal), verify with an authoritative source.

What’s the difference between US and UK gallons?

1 US gallon ≈ 3.785 L; 1 UK (imperial) gallon ≈ 4.546 L. Choose the correct unit in the converter when converting gallons.

Why do I see “ounce” and “fluid ounce”?

Ounce (oz) is mass/weight; fluid ounce (fl oz) is volume. They are not interchangeable. Use oz for weight (e.g. 4 oz cheese) and fl oz for volume (e.g. 8 fl oz water).

Can I use tounits offline?

After you’ve visited once, the app can work offline so you can convert without internet. Results are the same as when online.

Do you store my conversions?

We only store your recent queries and theme preference in your browser (local storage). We don’t send that data to our servers. See our Privacy Policy.