About OuncesExplained
Measurements, conversions & the story behind them.
Our Mission
Measurement should be simple — but anyone who has wondered whether an “ounce” means weight or volume, or why a US pint isn’t the same as a British one, knows it often isn’t. OuncesExplained exists to make everyday conversions fast and accurate, and to explain the fascinating history behind the units we use every day.
We built this site because most converters give you a number and nothing else. We wanted to also answer the why: why there are four different kinds of ounce, how the metric system came to be, and where units like the foot, the pound, and the gallon actually came from.
What You’ll Find Here
Instant Converters
Length, weight, volume, temperature, area & speed — all working offline.
The Ounce Explained
Avoirdupois, troy, fluid, and apothecary ounces — finally untangled.
History & Context
From Egyptian cubits to the 2019 SI redefinition of the kilogram.
Quick Reference
Anchor equivalences and mnemonics to keep conversions in your head.
Accuracy & Sources
Every conversion factor on this site is based on internationally agreed definitions — the inch is exactly 2.54 cm, the avoirdupois pound is exactly 453.59237 g, and so on. Where a value is an approximation, we say so. The historical content is researched from reputable references on metrology and the history of science.
Found something that looks off? We’d genuinely like to know — accuracy matters to us. Please get in touch.
How the Tools Work
The unit converters run entirely in your browser. Each unit is stored as an exact factor relative to a base SI unit — metres for length, kilograms for mass, litres for volume — so converting from any unit to any other is a single, precise calculation rather than a chain of rounded steps. Temperature is handled separately with the proper offset formulas, because a degree Celsius and a degree Fahrenheit don’t share a zero point.
Because nothing is sent to a server, the converters keep working once the page has loaded, even if you lose your connection. The currency converter is the one exception: exchange rates change every day, so it fetches a daily reference rate and clearly labels it as such.
Who It’s For
Home cooks converting a recipe from another country. Travellers making sense of road signs, weather forecasts and prices abroad. Students who need to understand why a unit is defined the way it is, not just its value. Hobbyists — from woodworkers to coin collectors weighing precious metals in troy ounces — who need the right number the first time.
If you have ever stood in a kitchen wondering whether “8 oz” on a recipe means weight or volume, the kitchen conversions guide and The Ounce Explained were written for you.
Free & Independent
OuncesExplained is free to use and installable as an app on your phone or desktop. It is supported by advertising, which lets us keep the tools open to everyone without a paywall or sign-up.