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Percentage Calculator

X% of Y, percentage change, add or subtract a percent. All in one place.

By Sammy S. · Founder · AuthorUpdated for 2026

Of · (X/100)×YChange · ((New−Old)/Old)×100Add % · ×(1+X/100)Subtract % · ×(1−X/100)

Percentage calculator formulas

X% of Y: (X ÷ 100) × Y. % change: ((New − Old) ÷ Old) × 100. Add X%: Y × (1 + X/100). Subtract X%: Y × (1 − X/100).

Your inputs

Pick a mode and enter numbers

What is X% of Y?

(X ÷ 100) × Y

What is X% of Y?

(X ÷ 100) × Y

30

15% of 200 = 30

15%

Percent (X)

200

Of (Y)

Quick tip

Multiply the percent by the number, then divide by 100 — or convert the percent to a decimal first (0.15 × 200).

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Common percentage conversions

FractionPercentFractionPercent
1/425%3/475%
1/250%1/520%
1/333.33%2/366.67%
1/1010%1/812.5%
1/205%1/1001%

When to use a percentage calculator

Percentages appear in tips (15%, 20%), sales tax, pay raises (3% increase), discounts, tax rates, and investment returns. Use our tip calculator, sales tax calculator, or pay raise calculator for those specific cases.

Common questions about percentages

How do I calculate X% of Y?

Convert the percentage to a decimal (divide by 100) and multiply by Y. X% of Y = (X ÷ 100) × Y. Example: 15% of $80 = 0.15 × 80 = $12. Or: 20% of 250 = (20 ÷ 100) × 250 = 50. Use the "X% of Y" tab in the calculator above for instant results.

How do I calculate percentage increase or decrease?

Percentage change = ((New − Old) ÷ Old) × 100. For an increase: $100 → $120 = (20 ÷ 100) × 100 = 20% increase. For a decrease: $100 → $80 = (-20 ÷ 100) × 100 = -20% (or 20% decrease). This formula works for prices, salaries, and any numeric change. Use the "% change" tab in the calculator.

How do I add or subtract a percentage?

Add X%: multiply by (1 + X/100). $100 + 8% = $100 × 1.08 = $108. Subtract X%: multiply by (1 − X/100). $100 − 15% = $100 × 0.85 = $85. Useful for discounts, sales tax, markups, and tips.

What's the difference between percentage point and percent?

A percentage point is the absolute difference between two percentages. If a rate goes from 10% to 15%, that's a 5 percentage point increase. A percent (relative change) would be (15 − 10) ÷ 10 = 50%—the rate increased by 50% of its original value. In news and finance, "the Fed raised rates by 0.25 percentage points" means the quoted rate level rose by 0.25 percentage points (for example from 5.00% to 5.25%), not a relative increase of 0.25% of the previous rate.

How do I reverse a percentage (find the original before a markup or discount)?

If you have a final amount after a percentage change, divide by the multiplier. After 20% markup: $120 ÷ 1.20 = $100 original. After 15% discount: $85 ÷ 0.85 = $100 original. For "what was the price before tax?" use our sales tax calculator in remove-tax mode.

Frequently asked questions

Percentage increase = ((new value − old value) ÷ old value) × 100. Example: $100 to $120 is (20 ÷ 100) × 100 = 20% increase. Use the % change tab above.

20% of $50 = 0.20 × 50 = $10. Use the "X% of Y" tab: enter 20 for X and 50 for Y.

Multiply by 1.10. Example: $100 + 10% = $100 × 1.10 = $110. Or: $100 + (10% of $100) = $100 + $10 = $110. Use the Add % tab.

Same formula as increase: ((new − old) ÷ old) × 100. A decrease gives a negative result. Example: $100 to $80 = −20%.

A percentage point is the absolute difference between two percentages. Going from 10% to 15% is a 5 percentage point increase, but a 50% relative increase ((15 − 10) ÷ 10). Relative percent compares to the old value; percentage points describe how many points the rate moved.

Multiply by 0.85 (or subtract 15% of the original). Example: $80 − 15% = $80 × 0.85 = $68. Use the Subtract % tab.

Result = (X ÷ 100) × Y. Example: 12% of 250 = 0.12 × 250 = 30.

If 25% of a number equals 40, divide 40 by 0.25: 40 ÷ 0.25 = 160. In general: whole = part ÷ (percent ÷ 100).

Each step uses a different base. $100 − 20% = $80; $80 + 20% = $96. The second 20% is applied to the smaller amount, so you end below the start.

Tip = bill × 0.18. Example: $64 × 0.18 = $11.52. Total with tip = bill × 1.18. Use Add % with the bill as the original number.

Percent = (part ÷ whole) × 100. Example: 30 is what percent of 200? (30 ÷ 200) × 100 = 15%. This calculator’s X% of Y tab solves the forward problem; rearrange as needed for the reverse.

A 50% increase means new = old × 1.5 (half again as much). Doubling is a 100% increase (old × 2). They are not the same.

Apply them in sequence on the remaining balance. A 20% off then 10% off of $100: $100 × 0.80 = $80, then $80 × 0.90 = $72 — which is 28% total off, not 30%.

Divide numerator by denominator, then multiply by 100. Example: 3/4 = 0.75 = 75%. See the common conversions table on this page for frequent fractions.

Multiply by 100 and add a % sign. Example: 0.125 = 12.5%. Divide a percentage by 100 to get the decimal.

Yes. Growth or ratios can exceed 100%. Example: $50 to $150 is a 200% increase ((150 − 50) ÷ 50). "200% of" a number means twice that number.

Markup is often percent of cost (selling − cost) ÷ cost. Margin is percent of selling price (selling − cost) ÷ selling. A 25% markup is not the same as a 25% margin.

It uses standard arithmetic rounded to two decimal places for display. Extremely large or tiny values may still show floating-point quirks in the browser — treat results as ordinary calculator math.

The conventional formula uses the old (starting) value as the base: ((new − old) ÷ old) × 100. Using the new value as the base is a different measure and will disagree.

If something is reduced by X%, what remains is (100 − X)% of the original. Example: after a 30% cut, 70% remains — multiply by 0.70.

Absolute change is new − old (e.g. +$20). Percent change scales that difference by the starting value so you can compare moves of different sizes.

You can estimate simple "add tax %" or "take X% off" math here. For full paycheck, sales tax by state, or income tax brackets, use the dedicated tax and paycheck calculators on this site — they model withholding and local rules.

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Last updated: 2026-03-31 · For educational use; verify critical calculations independently.