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Percentage Calculator

Solve every common percentage problem: find a percentage of a number, calculate what percentage one value is of another, work out percentage change, and reverse-calculate the original value. The formula used is shown for each calculation.

What is X% of Y?

X is what % of Y?

Percentage Change (Increase / Decrease)

Add or Remove a Percentage

Quick Examples

  • 15% of 200 = 30
  • 50 is 25% of 200
  • 100→150 = +50% change
  • 100 + 20% = 120
  • 100 - 20% = 80

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Free Percentage Calculator

Four essential percentage calculators in one tool: find what percentage a number is of another, calculate a percentage of a number, compute percentage change between two values, and add or remove a percentage from any number. Instant results with supporting explanations.

Features

Four Calculator Types

What is X% of Y, X is what % of Y, percentage change, and add/remove percentage.

Instant Results

Results appear immediately as you type, with no need to press calculate.

Formula Display

See the calculation formula alongside the result for learning and verification.

Copy Results

Copy individual results to clipboard with one click.

Clear & Reset

Reset any calculator instantly to start a new calculation.

Fully Private

All calculations are performed locally — no data is sent anywhere.

Who Uses This Tool?

Shoppers & Bargain HuntersCalculate sale prices, discounts and VAT/tax amounts quickly while shopping.
Finance ProfessionalsCompute profit margins, commission amounts and budget variances.
StudentsSolve percentage problems for maths, statistics and science coursework.
AnalystsCalculate percentage changes in data series, growth rates and KPI changes.

Common Questions

How do I calculate a percentage of a number?
Multiply the number by the percentage divided by 100. For example: 20% of 150 = 150 × (20/100) = 150 × 0.2 = 30.
How do I calculate percentage change?
Percentage change = ((New Value - Old Value) / |Old Value|) × 100. A positive result is an increase, negative is a decrease.
What is the difference between percentage and percentage points?
Percentage points measure the arithmetic difference between two percentages. If interest rates rise from 2% to 5%, that is a 3 percentage point increase — but a 150% increase in the rate itself.
How do I remove a percentage from a price (e.g., strip VAT)?
Divide the gross price by (1 + VAT rate/100). For 20% VAT: net price = gross / 1.2. Do not simply subtract 20% — that gives the wrong answer.

Pro Tip

To remove a percentage (like VAT) from a price, do NOT subtract the percentage directly. If a price includes 20% VAT, divide by 1.2 — not subtract 20%. Subtracting 20% from £120 gives £96, not £100 (the actual net price).

Did You Know?

Per centum
Latin Origin of Percent
"Per cent" comes from the Latin "per centum" meaning "by the hundred." The % symbol evolved from the Italian abbreviation "per cento" (p/c), which gradually compressed into the modern % symbol over several centuries of commercial use.
80/20
The Pareto Principle
The Pareto Principle (80/20 rule) states that roughly 80% of effects come from 20% of causes. Vilfredo Pareto observed in 1896 that 80% of Italy's land was owned by 20% of the population. The ratio appears across business (80% of revenue from 20% of clients), software bugs and countless other domains.
7.2%
Average Annual Stock Market Return
The US S&P 500 has returned approximately 10% annually on average since 1926, or ~7.2% after inflation. A $10,000 investment growing at 7.2% annually doubles every 10 years (Rule of 72: 72 ÷ rate ≈ years to double).

Common Percentage Calculations

GoalFormulaExample
X% of YY × (X ÷ 100)20% of 150 = 150 × 0.2 = 30
X is what % of Y(X ÷ Y) × 10030 is what % of 150? = (30÷150)×100 = 20%
% increase((New − Old) ÷ Old) × 100150→180: ((180-150)÷150)×100 = 20%
% decrease((Old − New) ÷ Old) × 100200→150: ((200-150)÷200)×100 = 25%
Add X% to YY × (1 + X/100)Add 20% to 150: 150 × 1.2 = 180
Remove X% from YY × (1 − X/100)Remove 20% from 150: 150 × 0.8 = 120
Y without VAT (X%)Y ÷ (1 + X/100)£120 ex 20% VAT: 120 ÷ 1.2 = £100
Y with X% tipY × (1 + X/100)$45 + 18% tip: 45 × 1.18 = $53.10

You May Also Ask

What is the Rule of 72?
The Rule of 72 is a mental math shortcut to estimate how long it takes money to double: divide 72 by the annual interest rate. At 6% annual return: 72 ÷ 6 = 12 years to double. At 9%: 72 ÷ 9 = 8 years. At 1% (savings account): 72 years. This rule is remarkably accurate for rates between 2–20% and illustrates why higher returns matter so much over long periods.
What is the difference between percentage points and percent change?
If interest rates rise from 3% to 5%, that is a 2 percentage point increase — simple arithmetic difference. But it's a 66.7% increase in the rate itself (2/3 × 100). Politicians and media often exploit this ambiguity — "crime rose by 50%" sounds alarming; "crime rose by 0.0003 percentage points" is the same fact. Always check which is being used.
How do compound vs simple interest percentages differ?
Simple interest: you earn the same % on your original investment each year. On $1,000 at 10%: earn $100/year, $1,000 total after 10 years. Compound interest: you earn % on both original + accumulated interest. On $1,000 at 10%: earn $100 in year 1, $110 in year 2 (on $1,100), ..., $1,594 total after 10 years. Einstein allegedly called compound interest "the eighth wonder of the world."

Common Mistakes

Removing a percentage by subtracting it directly
To remove 20% VAT from £120: many people subtract 20% (£24) to get £96. Wrong — the correct answer is £100. When £100 has 20% added, it becomes £120. So £120 ÷ 1.2 = £100.
To remove X% from a gross amount, divide by (1 + X/100), not subtract X%.
Confusing percent increase and percent of
"A 50% increase in $100 is $50" — correct ($150 total). "50% of $100 is $50" — also correct, but "of" and "increase" are very different!
Use "of" vs "increase" precisely. A 200% increase takes $100 to $300, not $200.
Stacking percentages additively
10% off, then another 10% off is not 20% off. First: $100 × 0.9 = $90. Second: $90 × 0.9 = $81. Total discount: 19%, not 20%.
Percentage discounts compound multiplicatively: (1-a%) × (1-b%) — always calculate sequentially.