Question 1

Is Universal Unit Converter free?

Accepted Answer

Yes — completely free, with no sign-up, no account, and no usage limits. Every converter on the site is available to everyone.

Question 2

How accurate are the conversions?

Accepted Answer

We use internationally defined conversion constants wherever they exist (for example, 1 inch is exactly 25.4 mm and 1 lb is exactly 453.59237 g), and you can display up to 10 decimal places or scientific notation.

Question 3

Do I need to press a convert button?

Accepted Answer

No. Results update in real time as you type — the answer changes with every keystroke.

Question 4

Where do currency exchange rates come from?

Accepted Answer

Rates are fetched automatically from a reliable open exchange-rate API and cached briefly for speed. The exact last-updated timestamp is shown under the currency converter.

Question 5

Where are my favorites and recent conversions stored?

Accepted Answer

In your browser's local storage, on your device only. Clearing your browser data removes them; we never see them.

Question 6

Can I use the converter offline?

Accepted Answer

All unit converters work fully offline once the page has loaded. Currency conversion uses the most recently cached rates when no connection is available.

Question 7

How do I convert in the opposite direction?

Accepted Answer

Click the swap button between the two unit fields — it flips the units and carries your result over as the new input.

Question 8

Can I print or save a conversion?

Accepted Answer

Yes. Use the printer icon on any converter: it opens your browser's print dialog, where you can also choose 'Save as PDF' to download the result.

Question 9

Why doesn't 1 cup of flour equal 1 cup of liquid when converting to grams?

Accepted Answer

Volume-to-weight conversions depend entirely on density. Dry ingredients like flour or sugar have varying bulk densities compared to liquids like water or milk, so converting volume to mass requires selecting a specific ingredient rather than using a single direct factor.

Question 10

Why are US gallons different from UK (Imperial) gallons?

Accepted Answer

The US Customary system and the British Imperial system use different historical standards for volume. A UK gallon (≈ 4.546 liters) is roughly 20% larger than a US liquid gallon (≈ 3.785 liters), so ensure you select the correct region's unit for liquid conversions.

Question 11

Can I convert compound units like feet + inches or hours + minutes together?

Accepted Answer

Most single-field converters only accept one total numeric value at a time. To convert a value like "5 feet 8 inches," convert the inches to a decimal fraction of a foot first (8 ÷ 12 = 0.67 ft) and enter the combined value (5.67 ft).

Frequently asked questions