Frequently asked questions
Why doesn't the US use metric?
The US came close — the Metric Conversion Act of 1975 made metric the preferred system, and the Omnibus Trade and Competitiveness Act of 1988 made it the official system for federal agencies. But voluntary adoption meant most everyday use never switched, and the US remains one of only three countries (with Myanmar and Liberia) not officially metric in daily life.
What is the difference between US and imperial fluid ounces?
A US fluid ounce is 29.5735 ml; an imperial fluid ounce is 28.4131 ml — about 4% smaller. A US gallon is 3.785 litres; an imperial gallon is 4.546 litres. Always check which system a recipe or specification uses.
How do I quickly convert Celsius to Fahrenheit in my head?
Double the Celsius temperature, subtract 10%, then add 32. For example: 20°C → 40 − 4 + 32 = 68°F. The exact formula is F = C × 9/5 + 32.
Is my data uploaded anywhere?
No. All conversions run in your browser using exact formulas. Nothing is sent to a server.