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The percentage calculator covers the calculations people reach for most often, in one place: finding a percentage of a value, expressing one number as a percentage of another, finding the base value behind a percentage, percentage increase and decrease, and the percentage change or difference between two numbers.

Percentages are just fractions of 100, but the everyday questions take different forms, and it is easy to mix them up. Having each as its own mode means you pick the question you actually have rather than rearranging a formula by hand.

Each mode shows a clear result plus a short sentence that spells out the calculation, so you can check the logic at a glance and trust the answer.

It is handy across daily life: discounts and sale prices, tips, taxes and VAT, interest, grades, statistics, and any quick share-of-a-total question.

A couple of the trickier ones are worth knowing. To remove a percentage already included in a price, you divide rather than subtract, since adding 20 percent and removing 20 percent are not the same operation.

Results are shown with up to two decimal places for readability, but the full value is used in the maths. Nothing is sent anywhere: everything runs in your browser.