How do I calculate percent change?

Percent Change = ((New − Old) / Old) × 100. A positive result means an increase; a negative result means a decrease. Example: a price rising from $80 to $100 is a 25% increase.

How do I find the original value from a percentage?

Original = Part ÷ (Percent / 100). Example: if 50 is 25% of X, then X = 50 ÷ 0.25 = 200.

How do I calculate a discount?

Sale price = Original price × (1 − Discount% / 100). For a 30% discount on $250: $250 × 0.70 = $175. Or use the 'Percent of' tab: 70% of 250 = 175.

What is a quick way to calculate 10% of any number?

Move the decimal point one place to the left. 10% of 350 = 35. For 5%, halve that: 17.5. For 20%, double it: 70.

How do I calculate percentage increase for a pay rise?

Percent Change = ((New Salary − Old Salary) / Old Salary) × 100. If your salary goes from $55,000 to $60,000: ((60,000 − 55,000) / 55,000) × 100 = 9.09% raise.

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Percentage Calculator

Calculate percent of a number, percent change, or reverse percentage instantly.

Percent (%)Number

Result: 25% of 200 = 50

What is a percentage?

Percentage means "per hundred" — it expresses a number as a fraction of 100. Percentages appear everywhere: tax rates, exam scores, discounts, interest rates, and statistical data. Knowing how to calculate them quickly saves time in everyday decisions.

%Percentage Calculator

Calculate any percentage with ease using the percent-of formula.

≈Evaluations

Recognize patterns by calculating percent limits.

↕Percent change

Find out percent a given value has risen or fallen.

↩Reverse percent

Given the result and percent, find the original value.

Percentage formulas

1. Percent of a number

Result = (Percent / 100) × Number

Example: What is 15% of 80? (15 / 100) × 80 = 12

2. Percent change

Change% = ((New − Old) / Old) × 100

Example: A jacket goes from $120 to $90. Change = ((90 − 120) / 120) × 100 = −25% (a 25% discount)

3. Reverse percentage

Original = Part ÷ (Percent / 100)

Example: After a 20% discount a laptop costs $640. What was the original price? 640 ÷ 0.80 = $800

Real-world examples

Exam score

You answered 42 out of 55 questions correctly. Score = (42 / 55) × 100 = 76.4%

Sales tax

A $35 book with 8% sales tax. Tax = 8% of 35 = $2.80. Total = $37.80

Pay raise

Salary rises from $52,000 to $57,200. Raise = ((57,200 − 52,000) / 52,000) × 100 = 10%

Investment return

Portfolio grew from $10,000 to $13,500 over two years. Return = ((13,500 − 10,000) / 10,000) × 100 = 35%

Quick mental math shortcuts

10% — move the decimal point one place left (10% of 340 = 34)
5% — halve the 10% result (5% of 340 = 17)
25% — divide by 4 (25% of 340 = 85)
50% — divide by 2 (50% of 340 = 170)
1% — move the decimal two places left (1% of 340 = 3.4), then multiply for any other percent

Frequently Asked Questions

Percentage = (Part / Whole) × 100. For example, 25 out of 200 = (25/200) × 100 = 12.5%.