Online calculators

Calculators for everyday sums

This section brings together simple calculators for the sums people do all the time: checking a sale price, reading an invoice, planning a budget or working out what a pay rise is really worth. There is no formula to remember and no spreadsheet to open. You type your numbers and the answer appears straight away, then changes with every keystroke.

The first tool in the family is the percentage calculator. It puts six sums on a single page: x% of a number, what percent one value is of another, the percentage change between two amounts, an increase, a discount, and the original value before a change, which is handy for taking VAT back off a price. Each block is laid out as a sentence to complete, so it is hard to get the numbers the wrong way round.

All the maths is done in your browser: the numbers you type are not sent anywhere and no account is needed. The pages work on a phone as well as on a computer, with the numeric keypad for typing. More calculators will join this page.