% Percentage Calculator

Solve any percentage problem instantly — what is X% of Y, percentage change, reverse percentage and more.

Percentage Calculator

Six types of percentage calculations — all free, all instant

1 What is X% of Y?

What is % of ?
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2 X is what % of Y?

is what % of ?
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3 Percentage Change (Increase / Decrease)

From to
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4 Increase / Decrease a Number by %

increased by %
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5 Reverse Percentage — Find the Original Number

is % of what number?
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6 Percentage Difference Between Two Numbers

Between and
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How to Calculate Percentages

This calculator solves all six common percentage problems in one place. No need to remember formulas — just enter your numbers and get the answer instantly.

1. What is X% of Y?

Multiply Y by X and divide by 100. Example: 15% of 200 = (200 × 15) ÷ 100 = 30. Use this for tips, discounts, tax amounts and commission calculations.

2. X is What % of Y?

Divide X by Y and multiply by 100. Example: 30 is what % of 150 = (30 ÷ 150) × 100 = 20%. Use this for exam scores, survey results and proportions.

3. Percentage Change

Subtract old from new, divide by old, multiply by 100. Example: from 80 to 100 = ((100−80) ÷ 80) × 100 = +25%. Use this for price changes, growth rates and performance tracking.

4. Increase / Decrease by %

To increase: multiply by (1 + percent/100). To decrease: multiply by (1 − percent/100). Example: 200 increased by 15% = 200 × 1.15 = 230.

5. Reverse Percentage

Divide the value by the percentage and multiply by 100. Example: 85 is 70% of what? = (85 ÷ 70) × 100 = 121.43. Use this when you know the result and percentage but need the original.

6. Percentage Difference

Divide the absolute difference by the average of both numbers, multiply by 100. Example: between 40 and 60 = (|60−40| ÷ ((40+60)÷2)) × 100 = 40%. Used when neither value is the reference point.

Frequently Asked Questions

What is the difference between percentage change and percentage difference? +
Percentage change has a clear direction — from an old value to a new value (increase or decrease). Percentage difference is used when there is no old/new relationship — it measures how different two values are relative to their average. Use percentage change for before/after comparisons and percentage difference for comparing two independent values.
How do I calculate a tip? +
Use calculator 1 — "What is X% of Y?". Enter the tip percentage (e.g. 15) and the bill amount. For a 5 bill with 15% tip: 15% of 85 = 2.75 tip, total = 7.75.
How do I calculate a discount? +
Use calculator 4 — "Decrease a number by %". Enter the original price and the discount percentage. For a 20 item with 25% off: 120 decreased by 25% = 0.
How do I find the original price before a discount? +
Use calculator 5 — "Reverse Percentage". If an item costs 5 after a 25% discount, enter 75 is 75% of what? Answer: 00 was the original price.