Percentage Calculator - Find % of a Number, % Change & More

% Choose a Calculation

What is % of ?

is what % of ?

From to is what % change?

increased by % = ?

All 4 Percentage Formulas

1. X% of Y

Result = (X ÷ 100) × Y

Example: 25% of 200 = (25÷100) × 200 = 50

2. X is what % of Y

Result = (X ÷ Y) × 100

Example: 30 is what % of 120 (30÷120) × 100 = 25%

3. Percentage Change (X to Y)

Result = ((Y - X) ÷ X) × 100

Example: 80 to 100 ((100-80)÷80) × 100 = +25%

4. Number After a Percent Change

Increase: Result = X × (1 + Y/100)
Decrease: Result = X × (1 - Y/100)

Example: 100 increased by 20% = 100 × 1.20 = 120

Common Percentage Questions

15% of 85 (tip calculation)

= 12.75

45 is what % of 180 (test score)

= 25%

Price went from 50 to 65

= +30% increase

Value dropped from 200 to 150

= -25% decrease

120 decreased by 20%

= 96

Frequently Asked Questions

Multiply the number by the percentage, then divide by 100. For example, to find 25% of 200: 200 × 25 ÷ 100 = 50. You can also convert the percentage to a decimal first (25% = 0.25) and multiply directly: 200 × 0.25 = 50.

Divide the part by the whole, then multiply by 100. For example, to find what percent 30 is of 120: (30 ÷ 120) × 100 = 25%. This tells you 30 is 25% of 120.

Subtract the original value from the new value, divide by the original value, then multiply by 100. The formula is: ((New Value - Original Value) ÷ Original Value) × 100. A positive result is a percentage increase; a negative result is a percentage decrease. For example, going from 80 to 100 is a (100-80)÷80×100 = 25% increase.

Percentage points measure the raw difference between two percentages, while percent change measures the relative change. If interest rates rise from 5% to 7%, that's a 2 percentage point increase, but it's a (7-5)÷5×100 = 40% relative increase in the rate itself. These two numbers are easy to confuse but describe very different magnitudes, especially in news headlines about rates, taxes, or survey results.

Divide the new (increased) value by (1 + percentage/100). For example, if a price increased by 20% to become $120, the original price was 120 ÷ 1.20 = $100. This is different from simply subtracting 20% of $120, which would incorrectly give $96.

Percentage Calculator - Four Ways to Calculate Percentages Instantly

"Percentage" questions come in more forms than people expect - finding a tip, checking a test score, understanding a price change, or reversing a discount to find the original price all use slightly different math. This calculator covers the four most common percentage calculations in one place, each with a plain-English sentence format so you never have to guess which formula applies.

Quick reference: X% of Y = (X÷100)×Y · X is what % of Y = (X÷Y)×100 · % change = ((Y-X)÷X)×100

The Four Percentage Calculations Explained

X% of Y: The most common calculation - used for tips, taxes, discounts, and commissions. "What is 15% of $85?"
X is what % of Y: Used to find a proportion - test scores, completion rates, or market share. "45 out of 180 is what percent?"
Percentage change: Used to describe growth or decline between two values - price changes, population growth, stock performance. "Sales went from 80 to 100 units - what's the percent change?"
Number after a percent change: Used to apply a known percentage increase or decrease to a starting number - sale prices, raises, or growth projections. "What is $100 after a 20% increase?"

A Common Mistake: Reversing a Percentage Increase

If a price increases by 20% to become $120, it's tempting to find the original price by simply subtracting 20% of $120 (which gives $96) - but this is incorrect. The correct method divides by (1 + the percentage as a decimal): $120 ÷ 1.20 = $100, the actual original price. This mistake is common enough that it's worth double-checking any time you're working backward from a percentage change, particularly with sale prices and tax calculations.

Percentage Points vs. Percent Change

These two terms are frequently confused in news and finance. If a survey result moves from 40% to 50% approval, that is a 10 percentage point increase, but it is also a ((50-40)÷40)×100 = 25% relative increase in approval. Both statements are true but describe different things - percentage points measure the raw gap between two percentages, while percent change measures how large that gap is relative to the starting value.

How this calculator works, and where the numbers come from

The Percentage Calculator applies the standard formula for this calculation to the values you enter and updates the result as you type. The calculation itself happens in your browser, and the page explains the method so you can check any result by hand.

Please note: Results are provided for general information and are calculated from the values you enter.

Sources and further reading

Learn more

Read our guide: Percentage Traps: Markup vs Margin, Stacked Discounts and More

Last reviewed: October 6, 2026 by the CalcQube Editorial Team. See our editorial policy for how we build and check calculators, or report an error.

% Percentage Calculator