Percent calculator
Calculate a whole list of percentage expressions at once, one per line.
Percent calculator
Paste a list of percentage expressions and get every result at once, instead of running one calculation at a time. Each line becomes "<expression> = <result>", so you can process an entire batch — invoice line items, grading curves, tip calculations, sales reports — in a single pass and copy the whole answer sheet back out.
The tool understands three plain-English shapes. Write "20% of 80" to find how much a percentage is of a number, useful for discounts, taxes and commissions. Write "25 is what % of 200" to work out what share one number represents of another, handy for conversion rates or scoring a test. And write "80 +20%" or "80 -20%" to increase or decrease a value by a percentage in one step, which covers price markups, salary raises and stock drop calculations. Numbers can be negative or carry decimals, and the "is what %" form correctly flags dividing by zero instead of returning a broken result.
Lines that do not match any of the three shapes are never dropped or allowed to crash the whole batch — they pass through with a short note so you can spot and fix a typo without losing the rest of your list. Results round to at most two decimal places with no trailing zeros, so the output stays easy to scan and easy to copy straight into a spreadsheet or email. Recalculation happens live as you type, on a short debounce, so a pasted list of dozens of lines updates in a fraction of a second.
Everything runs locally in your browser using plain JavaScript — no expression, number or result is ever sent to a server. That makes it safe to paste in figures from an unpublished budget, a client invoice or a private grading sheet, since the data never leaves your device and disappears the moment you close the tab.