Math tools
10 free math tools · Percentages, units and numbers
Conversions and calculations that are easy to get subtly wrong in your head: percentage change versus percentage points, unit conversions with the right factor, exact fraction arithmetic that does not drift into decimals. Where a formula is involved, the tool shows it, so you can check the working rather than trust the output.
All math tools
- Percentage calculator Percentage change, apply % to a value, margin & markup.
- Unit converter Length, mass, volume, temperature conversions.
- Fraction calculator Exact fraction arithmetic, simplified, with mixed numbers.
- Average calculator Mean, median, mode, range, deviation and quartiles.
- Ratio calculator Simplify a ratio, see shares, and solve a : b = c : x.
- Number base converter Convert between binary, octal, decimal, hex and base 36.
- Roman numeral converter Numbers to Roman numerals and back, with validation.
- GCD & LCM calculator Greatest common divisor and lowest common multiple.
- Quadratic equation solver Solve ax² + bx + c = 0, including complex roots.
- Scientific notation converter Convert to scientific and engineering notation.
Guides
- Percent vs percentage points: a small wording difference that changes the number An interest rate rising from 2% to 3% is one percentage point — but a 50% increase. Why the two phrasings differ, and the percentage traps hiding in everyday claims.
- Ounces vs fluid ounces: they are not the same unit An ounce measures weight, a fluid ounce measures volume, and they only coincide for water. Why "8 oz of chicken" and "8 oz of milk" are different kinds of quantity.
- MB vs MiB: why a 1 TB drive shows up as 931 GB Drive makers count in powers of 1000, operating systems in powers of 1024. Nobody is lying — the maths behind the missing gigabytes, and what KiB and MiB mean.