Percentage Calculator - Calculate Percentages Free Online Percentage Calculator

What is a Percentage?

A percentage is a way of expressing a number as a fraction of 100. The word comes from the Latin per centum, meaning “by the hundred.” Percentages are used everywhere — from discounts and taxes to exam scores and data analysis — making them one of the most practical mathematical concepts in daily life.

Percentage Formulas

Examples

• 25% of 200: (25 ÷ 100) × 200 = 50
• 30 is what % of 120? (30 ÷ 120) × 100 = 25%
• Change from 80 to 100: ((100 − 80) ÷ 80) × 100 = 25% increase
• Change from 100 to 80: ((80 − 100) ÷ 100) × 100 = 20% decrease

Percentage Tips & Tricks

• 10% shortcut: Divide any number by 10 to get 10%. For example, 10% of 450 is 45.
• Reverse trick: 8% of 25 is the same as 25% of 8 (both equal 2). Swap to pick the easier calculation.
• Doubling & halving: 50% is half, 25% is half of half, 75% is half + quarter.
• Converting fractions: Divide numerator by denominator and multiply by 100. E.g., 3/8 = 0.375 × 100 = 37.5%.

Common Uses of Percentages

• Shopping Discounts: A 20% discount on ₹500 saves ₹100, so you pay ₹400.
• Exam Scores: Scoring 72 out of 90 gives (72÷90)×100 = 80%.
• Financial Growth: An investment growing from ₹10,000 to ₹12,500 is a 25% increase.
• Tax Calculations: 18% GST on ₹1,000 = ₹180 tax.
• Statistics & Data: Expressing survey results, market share, etc.

How This Calculator Works

1. Choose a mode: “X% of Y”, “X is ?% of Y”, or “% Change”.
2. Enter values: Type your numbers into the input fields.
3. Instant result: The answer, formula breakdown, and input summary update in real time.
4. Direction badge: In “% Change” mode, an increase/decrease badge shows the direction of change.