Find X% of Y, what percentage X is of Y, or the percentage change between two values, instantly.
What is __% of __?
__ is what % of __?
Percentage change from __ to __
This Percentage Calculator handles the three most common percentage problems in one place. Mode 1 — % of a number: enter 15% of 200 and get 30. Mode 2 — what percentage is X of Y: enter 30 and 200 to learn that 30 is 15% of 200. Mode 3 — percentage change: enter 80 as the original and 100 as the new value to see a 25% increase. Every answer is displayed alongside the exact formula used, so you can check the arithmetic or apply it elsewhere.
Percentages come up constantly in daily life, from discounts and tax to grades, growth rates and tips, and the mental arithmetic is easy to get wrong. This tool removes the chance of error and shows the working, which is useful when you need to explain or verify a calculation for someone else. Everything runs in your browser: no account needed, no data stored.
Reviewed by the ToolBrainy Team · Calculations run entirely in your browser · Last updated July 2026
The three tabs cover the three most common percentage questions. % of a number answers "what is X% of Y?" Use it for discounts, tips and tax. What % is X of Y answers "X is what percent of Y?" Use it to convert scores or express a part as a proportion. % change measures the increase or decrease between two values. Use it for growth rates, weight changes or price shifts.
Each mode shows two labeled inputs. In % of a number, enter the percentage first, then the whole number. In What % is X of Y, enter the smaller part as X and the total as Y. In % change, enter the starting value in "From" and the ending value in "To".
Click Calculate to see the answer. Below the result, the exact formula is shown, for example, 20% of 500 = 500 × (20 ÷ 100) = 100. You can use that formula to double-check the answer in a spreadsheet or share the working with someone else.
Calculations stay in your browser, nothing stored.
Covers every everyday percentage question.
Learn how each answer is worked out.
No signup, no limits and no watermarks, ever.
A jacket is £120 with 30% off. Mode 1: 30% of 120 = 36, so you save £36 and pay £84. Works for any sale: enter the discount percentage and the original price.
You scored 43 out of 55. Mode 2: 43 is what % of 55 = 78.2%. Useful for understanding where a raw mark sits within a grading scale, or for combining marks from differently weighted papers.
Your site had 800 visitors last month and 1,150 this month. Mode 3: % change from 800 to 1,150 = +43.75%. Useful for monthly reports, year-over-year comparisons, and tracking sales targets.
A product costs £200 before 20% VAT. Mode 1: 20% of 200 = 40, so the total is £240. Alternatively, use Mode 2 to find what share of an all-in price is tax.
Starting weight 95 kg, current weight 82 kg. Mode 3: % change from 95 to 82 = −13.7%. The negative sign confirms a reduction, useful for tracking any metric that should decrease over time.
The bill is $67 and you want to leave 15%. Mode 1: 15% of 67 = $10.05. Add that to the bill for a $77.05 total. For groups, calculate the full tip first, then divide by the number of people.
Select "% of a number", type 20 in the Percentage field and your number in the Number field, then click Calculate. For example, 20% of 500 = 100. The formula shown is 500 × (20 ÷ 100), which you can apply manually or in a spreadsheet.
Select "What % is X of Y", enter the part as X and the total as Y. The calculator divides X by Y and multiplies by 100. For example, 43 out of 55 = 78.18%. Use this mode when converting a raw score into a grade or expressing a subset as a share of a whole.
The formula is ((New − Old) ÷ Old) × 100. A positive result means an increase; a negative result means a decrease. For example, going from 80 to 100 gives ((100 − 80) ÷ 80) × 100 = 25% increase. Going from 100 to 80 gives −20%.
Percentages express a value relative to a whole. Percentage points measure the arithmetic difference between two percentages. If an interest rate rises from 3% to 5%, that is a 2 percentage-point increase, but it is also a 66.7% increase in the rate itself. This distinction matters in finance, statistics, and reporting where precision is important.
A negative percentage change means the value went down. A price dropping from £120 to £90 gives ((90 − 120) ÷ 120) × 100 = −25%. The magnitude tells you how large the drop was; the sign tells you the direction. If you only want the size of the change, ignore the minus sign.
Yes, completely free with no signup, no data sent to any server, and no limits on how many calculations you run. Everything happens locally in your browser.
No. The Percentage Calculator runs entirely in your web browser, so there is nothing to download or install — just open the page and start calculating.
To add X% to a number, multiply it by (1 + X ÷ 100) — for example, adding 20% to 50 gives 50 × 1.20 = 60. To subtract X%, multiply by (1 − X ÷ 100), so removing 20% from 50 gives 50 × 0.80 = 40. You can also work out the percentage in Mode 1 first, then add or subtract it.