Percentage Calculator

Useful for discounts, tips, exam marks, tax, commission, interest, price changes and any of the dozens of everyday moments where percentages appear.

How to use the percentage calculator

Pick the type of percentage question you have.

Enter your two numbers.

Read the answer and the formula used to get there.

Why use the Convert Now percentage calculator

Four modes

Percentage of, percent that, increase/decrease, and add/subtract.

Shows the formula

Every result explains the arithmetic so you can check or reuse it.

Live results

Answers update as you type – no submit button.

Free and private

No account, no limits, nothing uploaded.

The four questions people actually ask

Almost every percentage problem is one of four shapes. "What is 15% of 200?" is a straight multiplication. "30 is what percent of 200?" reverses it into a division. "Sales went from 200 to 250 – what is the increase?" compares two values against the original. And "add 15% to 200" applies a multiplier. Choosing the right one is most of the difficulty, which is why the calculator names them in plain language rather than making you translate your problem into algebra.

Percentage increase versus percentage points

A change from 20% to 25% is a five percentage point rise, but a 25% increase – and confusing the two is one of the most common mistakes in news reporting and business reporting alike. Percentage change is always measured against the original value, so use the increase/decrease mode with the old figure first and the new figure second, and the calculator handles the base correctly.

Why reversing a discount does not work

Take 20% off 100 and you get 80. Add 20% back to 80 and you get 96, not 100 – because the second percentage is calculated on the smaller number. This trips people up with tax-inclusive pricing and sale prices. To reverse a 20% discount, divide by 0.8 rather than adding 20%.

Read the guide: How to Calculate Percentage: Formulas & Examples

Frequently asked questions

How do I calculate a percentage of a number?

Choose "What is X% of Y?", enter the percentage and the number. The formula is (percentage ÷ 100) × number.

How do I find what percentage one number is of another?

Choose "X is what % of Y?" and enter both numbers. The formula is (part ÷ whole) × 100.

How do I calculate percentage increase?

Choose the increase/decrease mode, put the original value first and the new value second. The result is (new − old) ÷ old × 100.

How do I add or subtract a percentage?

Use the fourth mode. Adding 15% multiplies by 1.15; subtracting 15% multiplies by 0.85.

How do I reverse a percentage discount?

Divide by (1 − discount ÷ 100). To undo 20% off, divide the sale price by 0.8 – adding 20% back gives the wrong answer.

Is the calculator free?

Yes, with no limits or sign-up.