All calculators

Every calculator on the site, grouped by category — 20 pages in total. Each one is free, needs no sign-up, and shows the formula behind its result.

Finance

Mortgage Payment

Work out your monthly mortgage payment including taxes, insurance and PMI, then see exactly how much interest you will pay over the life of the loan.

Compound Interest

See what your savings grow into once interest starts earning interest, with regular contributions and any compounding frequency.

Health & Fitness

BMI

Work out your body mass index in metric or imperial units, see which WHO category it falls in, and find the weight range that would put you in the healthy band.

Math

Percentage

Answer all four of the common percentage questions — what is X% of Y, X is what percent of Y, percentage increase or decrease, and the original value before a change.

Unit Converters

Length

Convert between millimetres, centimetres, metres, kilometres, inches, feet, yards, miles and nautical miles using exact conversion factors.

Date & Time

Date Difference

Count the days, weeks, months and years between two dates, including an exact working-day count that skips weekends.

Business

Profit Margin

Turn cost and revenue into gross margin, markup and profit per unit — and work backwards from a target margin to the price you need to charge.

Everyday

Tip

Work out the tip and the total, split it across the table, and optionally round each share to something you can actually hand over.