Calculate percentages: find X% of a number, what percent one number is of another, or the total from a percentage.
📖 Standard Percentage FormulasFill in the fields on the left with your information, then press Calculate to see your result instantly. No sign-up required, and no data is sent anywhere — everything is calculated right in your browser.
Percentage is one of the most commonly used mathematical concepts in daily life, from calculating discounts and taxes to interest and grades. This calculator combines three common cases in one tool: the first is "X% of Y" to find the value of a certain percentage of a number; the second is "X is what % of Y" to find what percentage one number is of another; and the third is "X is Y% of an unknown number" to work out the original number if we know a percentage of it. Select the appropriate case from the list, and enter the two values to get the result instantly. All three cases rely on the same underlying relationship between a part, a whole, and a percentage — the calculator simply rearranges that relationship to solve for whichever of the three values is currently missing. Because a percentage is, by definition, a fraction expressed out of 100, every one of these three cases can also be checked by converting the percentage back into a plain fraction and confirming the arithmetic matches, a useful habit for catching an error before submitting a homework answer.
Nearly every percentage question that comes up in daily life, schoolwork, or business fits into one of only three patterns, and recognizing which pattern applies is usually the hardest part of the problem — the arithmetic itself is simple once the right formula is chosen.
The first and most familiar pattern is 'find X% of Y', used whenever a percentage needs to be converted into an actual amount: an 18% tip on a $60 bill, a 25% discount on a $80 jacket, or 7% sales tax on a purchase. The calculation is a single multiplication: convert the percentage to a decimal by dividing by 100, then multiply by the total.
The second pattern flips the question around: 'X is what percent of Y'. This is the pattern behind grade calculations (42 correct out of 50 questions), market share questions (a company's $12 million revenue out of a $150 million industry), and progress tracking (60 pages read out of a 240-page book). Here, the part is divided by the whole and multiplied by 100 to express the result as a percentage.
The third and least intuitive pattern is 'X is Y% of what number', used to reconstruct an original total from a known percentage of it. A common real example is a discounted price: if a jacket now costs $60 after a 25% discount, the original price is not simply $60 plus 25% of $60 — it requires dividing $60 by 0.75 (since $60 represents the remaining 75%), which highlights exactly why this case trips people up when solved by intuition instead of the correct formula.
Percentage literacy has measurable financial consequences. Confusing 'percentage of the original price' with 'percentage off the original price', or misreading a percentage change as a percentage of a different base, are documented sources of consumer misunderstanding in everything from credit card interest disclosures to sale advertising. Working through all three patterns with a reliable calculator — and checking that the answer makes intuitive sense (a discount should always produce a smaller number, an original-price problem should always produce a larger one) — builds the kind of numerical intuition that catches errors before they become costly mistakes on a bill, a grade, or a business decision.
Choose 'X% of Y', enter the discount percentage as X and the original price as Y to get the discount amount.
Yes, percentages above 100% are calculated the same way and are valid in cases like growth or markup.
It finds the original total when you only know a percentage of it and its resulting value.