Disclaimer

These converters are careful, and they are still only a reference. Where a wrong number would hurt someone or cost real money, check it against the source that governs your work.

Last updated: 18 September 2026.

General information only

UnitConverter publishes unit conversions for general reference and education. Nothing here is professional advice — not engineering, construction, navigational, medical, pharmaceutical, nutritional, chemical, financial, legal or safety advice — and no result should be treated as a substitute for a qualified professional, an instrument reading, or the specification you are working to.

Where our numbers come from

Every factor is taken from the defining standard for the unit — the international yard and pound agreement, the SI prefixes, the statutory definition of the US gallon — and each one is listed on the methodology page so you can check it rather than trust it. A pair and its reverse read the same stored factor, so they cannot disagree with each other.

We still make no warranty that a given result is accurate, current, complete or fit for your purpose. See section 7 of the terms of use.

Rounding is real

Displayed answers are rounded for readability. A rounded figure is not the exact value, and rounding compounds if you feed one result into the next calculation. Where precision matters, work from the exact factor on the methodology page rather than from the number on screen, and round only once, at the end.

Units with more than one meaning

Some unit names cover several different quantities. A US fluid ounce is not an Imperial fluid ounce; a US gallon is not a UK gallon; a fluid ounce measures volume while an ounce measures weight; a cup on a US recipe is not a metric cup. Each page says which definition it uses. If the page you are on does not match the definition your document, recipe or standard is using, the answer will be wrong for you even though the arithmetic is right.

High-stakes uses

Do not use this site as the sole basis for a medication dose, an infant feed, an anaesthetic volume, a structural or load calculation, an aviation or marine navigation figure, a laboratory formulation, a legal filing, a customs declaration or a contractual quantity. In those settings, use the tool your profession requires and have the figure checked by a person who is accountable for it.

External links and advertising

Pages here link to standards bodies and reference sources, which we do not control and are not responsible for. The site is funded by advertising served through Google AdSense; we do not select the individual adverts, do not endorse the advertisers or their products, and receive no commission on anything you buy from them. See the privacy policy for what the ad tag collects.

Report a wrong number

If a result looks wrong, tell us — arithmetic corrections are the highest-priority change this site accepts. Email [email protected] with the page, what you entered, what we showed and what you expected. See the contact page for what makes a report quick to act on.