Percentage Calculator

Calculate percentages, increases, and differences easily.

?% × ? = ?

Value

Result

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Reference Table

Percentage of the value entered in the second field

Working with Percentages

Overview

Percentages are mathematical shorthand for fractions out of 100 — a way to compare values regardless of their original scale. They appear everywhere: tax rates, interest, discounts, statistics, polls, grades, tips, and probabilities. Despite their simplicity, percentage problems trip up many people because the same phrase can mean different things — '20% more' increases by a fifth, while '20% of' takes only the fifth. This calculator handles all common percentage operations: basic percentage of a number, percentage change, finding what percent X is of Y, and reverse calculations.

How It Works

The four common percentage operations: (1) X% of Y = X × Y / 100, (2) Percentage change = (new − old) / old × 100, (3) X is what % of Y = X / Y × 100, (4) Reverse: Y is X% of what = Y × 100 / X. The calculator lets you switch between modes. All math is done with full floating-point precision, then rounded only for display. Multi-step percentages (e.g., '15% discount, then 8% tax') don't simply add — apply each in sequence.

When to Use This

Calculate tax-inclusive prices when shopping, restaurant tips, percentage of test/quiz scores, employee commission calculations, percentage weight loss/gain, investment returns, statistics in reports, and progress bars. Particularly useful for comparing 'X% off' vs 'X% cashback' deals — they often produce different effective discounts.

Frequently Asked Questions

What's the difference between 'increase by 20%' and 'multiply by 1.2'?

They're the same. Increase by 20% means add 20% of the original, which is the same as multiplying by 1.20. Similarly, decrease by 20% = multiply by 0.80.

How do I reverse a percentage change?

If price went from $100 to $120 (+20%), going back from $120 isn't −20% (that gives $96). It's $120 ÷ 1.20 = $100. Reversing percentage changes requires division, not subtraction.

What does 'percentage points' mean?

A unit of absolute difference between two percentages. If interest rose from 3% to 5%, that's a 2 percentage point increase (or 66.7% relative increase). Confusing the two is a common pitfall in news reports.