Calculators & Converters

Built for accuracy first

Every one of these tools keeps the full-precision figure internally and rounds only what you see, so changing the number of decimal places never changes the underlying answer. Conversion factors are the defined ones — an inch is exactly 0.0254 metres, a pound exactly 0.45359237 kilograms — and the awkward cases are handled rather than glossed over:

• Temperature converts with real formulas, because Celsius and Fahrenheit have different zero points.
• A gigabyte (1,000,000,000 bytes) and a gibibyte (1,073,741,824 bytes) are never treated as the same thing.
• US and Imperial gallons — and therefore US and UK MPG — are different units.
• Dates are counted as calendar dates. Nothing divides by 30 or 365 to get a month or a year.
• Nothing ever displays NaN, Infinity or a blank where a number should be. If a calculation has no answer, the tool says why.

Private by default

These calculators run entirely in your browser. Your date of birth, salary, loan details and health measurements are never sent to a server, because there is no server involved in the arithmetic. No account is needed and nothing is stored.