Percentage Calculator
Eight calculation modes in one tool: percent of, percent change, discount, tax, find the whole, and more — with instant work shown and visual charts.
Input
Result
25 / 200 × 100 = 12.5%
About this tool
This percentage calculator brings every everyday percent task into one page with eight one-click modes: "A is what % of B", "B% of A", percent change from X to Y, discount (price after a markdown), add tax, find the whole from a part, increase/decrease a value, and remove tax from a total. Each mode shows the result instantly, prints the one-line working so you can learn the method, and visualizes the answer with pie and bar charts. Whether you are studying, shopping a sale, or building a budget, you get an accurate number without a mental-math slip.
How to use
- 1 Pick the mode tab you need — percent of, % change, discount, add tax, find whole, increase/decrease, or pre-tax.
- 2 Type your two or three numbers, such as the price and the discount rate.
- 3 The answer and the one-line working appear instantly, with pie or bar charts to visualize it.
- 4 Switch tabs anytime to try another mode; nothing needs to be reset.
How it works
A percentage is a part out of 100. The core formulas this tool uses are: - A is what % of B = A / B × 100 (e.g. 25 / 200 × 100 = 12.5%) - B% of A = A × B / 100 (e.g. 15% of 80 = 12) - Percent change from X to Y = (Y − X) / X × 100 (e.g. 50 → 75 = +50%) - Discount: pay = price × (1 − D/100) (e.g. 1000 − 20% = 800, saving 200) - Add tax: total = price × (1 + T/100) (e.g. 1000 + 10% = 1100, tax 100) - Find the whole: whole = part / P × 100 (e.g. 20% is 50 → 250) When you chain several percentage changes you multiply the factors instead of adding the percentages, which is why two discounts never simply add up.
Frequently asked questions
How do I work out a discount and the final price?
Use the Discount tab: the amount saved is price × discount% and the price you pay is the rest. For example 1000 with 20% off saves 200 and you pay 800.
How do I add sales tax to a price?
Use the Add Tax tab: tax = price × rate% and the total is price + tax. A 1000 price with 10% tax adds 100 for a 1100 total. The Tax Excluded tab does the reverse, pulling the tax back out of a gross amount.
What is the difference between a percent and a percentage point?
If a rate rises from 3% to 5%, that is a 2 percentage-point rise, but the relative percent change is (5−3)/3 × 100 = 66.7%. Points are a difference; percent change is a ratio.
Does a 20% discount plus a 30% discount equal 50% off?
No. From 100, 20% off gives 80, then 30% off gives 56 — an effective 44% off. Percentage changes multiply, so they never simply add together.
What do the charts and the working line show?
The single working line prints the exact formula with your numbers so you can follow the method, while the pie and bar charts show the share of the whole and compare the sizes at a glance.
Related tools and uses
For sale prices and tax, a sales-tax or loan calculator is handy. To turn ratios into other forms, see fraction and decimal conversion, and for data summaries try the statistics tools. For homework, the equation solver handles word problems that involve percentages.