Free Percentage Calculator Online

Calculate percentages instantly — X% of a number, percentage change, increase/decrease by %. Free, no signup, works in your browser.

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How to Use the Percentage Calculator

This calculator handles four types of percentage problem in one place. Pick the mode that matches your question, enter your numbers, and get the answer instantly — no formula needed, no mental arithmetic required.

1

Pick your calculation type

Choose from four modes: X% of Y (e.g. what is 20% of 150?), X is what % of Y (e.g. 45 is what % of 180?), % Change (e.g. what is the % increase from 80 to 100?), or Increase/Decrease by % (e.g. what is $200 after a 30% discount?).

2

Enter your numbers

Type into the input fields — the result calculates and updates live as you type. There is no submit button; the answer appears immediately so you can try different values quickly.

3

Read and use your result

Copy the result for use in a report, invoice, grade sheet, or spreadsheet. Use the Reset button to clear all fields and start a fresh calculation in any mode.

Everyday percentage calculations explained

Calculating a discount price

Use "Decrease by %" mode. Enter the original price as the number and the discount percentage. Example: $250 item with 35% off → $250 decreased by 35% = $162.50. This is your final pay price after the discount is applied.

Calculating price including VAT or sales tax

Use "Increase by %" mode. Enter the pre-tax price and the tax rate. Example: $85 item with 8% sales tax → $85 increased by 8% = $91.80 total price. Works for VAT (UK, EU) or any regional sales tax.

Calculating a test score as a percentage

Use "X is what % of Y" mode. Enter your score as X and the total possible marks as Y. Example: 38 out of 50 → 38 ÷ 50 × 100 = 76%. Works for any scored assessment.

Calculating salary increase or pay cut

Use "% Change" mode to find the percentage difference between two amounts. Example: salary changed from $55,000 to $62,000 → (62,000 − 55,000) ÷ 55,000 × 100 = 12.7% increase. Works for any before/after comparison.

Calculating a tipping percentage

Use "X% of Y" mode. Enter 18 (or 20) as the percentage and your bill total as Y. Example: 18% of $67.50 → $12.15 tip. Add that to your bill for the total to pay.

Frequently Asked Questions

How do I calculate 20% of 150?

Use "X% of Y" mode. Enter 20 as the percentage and 150 as the number — result is 30. Formula: 20 ÷ 100 × 150 = 30.

How do I find a percentage increase from 80 to 100?

Use "% Change" mode. Enter 80 as From and 100 as To — the result is 25% increase. Formula: (100 − 80) ÷ 80 × 100 = 25%.

How do I calculate what percentage 45 is of 180?

Use "X is what % of Y" mode. Enter 45 as X and 180 as Y — the result is 25%. Formula: 45 ÷ 180 × 100 = 25%.

How do I calculate a discount price?

Use "Decrease by %" mode. Enter the original price as the number and the discount rate as the percentage. For example, $200 decreased by 30% = $140 — your final price after discount.

How do I calculate price including tax?

Use "Increase by %" mode. Enter the pre-tax price as the number and the tax rate as the percentage. Example: $85 increased by 8% = $91.80 (total price including tax).

How do I convert a test score to a grade percentage?

Use "X is what % of Y" mode. Enter your score as X and total possible points as Y. For example, 42 out of 50: 42 ÷ 50 × 100 = 84%.

Is data saved?

No. Everything runs in your browser. Nothing is stored or sent to any server.

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