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Percentage Calculators

Free tools for every percentage question — find what 15% of a number is, track how much a value changed, work backwards with the reverse percentage tool, or convert fractions and decimals to percentages. For financial applications like discounts and profit margins, see the finance calculators.

Which calculator do you need?

Find the right tool based on your question.

Find X% of a number (tip, tax, commission)What is X% of Y? →
Express one number as a % of anotherX is What % of Y? →
Find the original before a % was appliedReverse Percentage →
Measure how much a value rose or fellPercentage Change →
Calculate a sale price or discountPercent Off Calculator →
Convert a test score to a letter gradeGrade Calculator →
Calculate GPA from letter grades and creditsGPA Calculator →
Convert a fraction or decimal to %Fraction to Percent →

How percentages work

A percentage expresses one number as a fraction of 100. Every percentage problem reduces to one of three fundamental calculations:

P% of NFinding a part — e.g. 20% of $150 = $30. Use: N × (P ÷ 100).
X of Y = ?%Finding the rate — e.g. 30 out of 120 = 25%. Use: (X ÷ Y) × 100.
Change %Finding the change — e.g. $80 → $100 = 25% increase. Use: ((New − Old) ÷ Old) × 100.

Core Calculations

The fundamental operations — finding a part, a rate, or reversing a percentage.

Change & Comparison

Measuring how much something increased, decreased, or differs between two values.

Grades & Education

Convert scores to letter grades or calculate GPA from course results.

Conversions

Convert between fractions, decimals, and percentages.

Everyday Use

Tips, discounts, salary raises, and year-over-year changes.

Common lookups

Quick answers for the most searched percentage questions.

10% of 100

10

20% of 100

20

25% of 200

50

15% of 50

7.50

30% of 150

45

50% of 80

40

Common questions

What is the basic percentage formula?

Percentage = (Part ÷ Whole) × 100. For example, if 30 out of 150 students passed, the pass rate is (30 ÷ 150) × 100 = 20%. To find a percentage of a number, use: Result = (Percentage ÷ 100) × Number.

What's the difference between percentage change and percentage difference?

Percentage change requires a 'before' and 'after' — for example, sales rising from $400 to $500 is a 25% increase. Percentage difference has no direction — it just measures how far apart two values are, without implying one came first.

How do I find the original price before a discount?

Use the reverse percentage calculator. If a price is $85 after a 15% discount, divide $85 by 0.85 to get $100 — the original. The tool does this automatically.

Which calculator works for tips, tax, and commissions?

The 'What is X% of Y?' calculator covers all three — enter the rate and the base. For example: 18% tip on $47.50, 7% tax on $200, or 5% commission on $3,000.

How do I calculate a percentage increase in my head?

For 10%, move the decimal one place left (10% of $80 = $8). For 20%, double that ($16). For 5%, halve the 10% figure ($4). For 25%, divide by 4 ($20). These shortcuts work for any round percentage on any base.