Percentage Calculator
The Percentage Calculator handles the three questions percentages actually come in: what is X percent of Y, X is what percent of Y, and what is the percentage change between two values. How it works: you pick the question format, enter the numbers you have, and the tool applies the correct formula immediately — no remembering whether to multiply or divide, which is exactly where mental percentage math goes wrong under time pressure. Shoppers use it to compute real sale prices and compare discounts that are framed differently; diners use it for tips; students use it to work out what score a grade percentage represents; freelancers use it for tax set-asides and fee calculations; investors and savers use the change mode to see growth or decline in percentage terms rather than absolute numbers. The three-mode design matters because most percentage errors come from applying the right arithmetic to the wrong question format. Tip: for percentage change, double-check which value is the original — swapping the base inverts the answer, and a price that rose 50 percent needs a 33 percent cut to come back. You can also browse the other tools on the Spark Site home page or search the collection on the tool search page.