Converters

Every result at once. The usual converter gives you two dropdowns: pick a source, pick a target, read one number. But you convert to inches and then immediately wonder about centimetres. Showing the whole category answers the second question before you ask it.

Exact factors, and honest labels. An inch is defined as exactly 0.0254 metres, a pound as exactly 0.45359237 kilograms. Those are the numbers the arithmetic uses. Some units have no fixed size at all: a month, a year. The tool says so on the unit itself instead of burying an assumption in the answer.

Everyday units

Length covers metres, feet and miles. Weight covers kilograms, pounds and stones — and lists the three different tons separately, because they differ by up to 10%. Temperature handles the one conversion that needs addition as well as multiplication.

Land, liquid and motion

Area includes the dunam alongside acres and hectares. Volume keeps US and imperial gallons apart, since they differ by 20% under the same word. Speed covers km/h, mph and knots.

Computing

Data storage shows decimal and binary units side by side, which is the whole explanation for why a 1 TB drive reports as 931 GB. Number base converts binary, octal, decimal and hex with arbitrary-precision arithmetic, so large values stay exact.

Dates and numbers

Date difference counts real calendar days including working days. Age breaks that into years, months and days without the borrowing bug most calculators have. Percentage covers four separate questions, including recovering a pre-tax figure. Time units and time zones answer different questions — how long, and when. Roman numerals convert both ways with strict validation.