The Percentage Calculator handles the three most common percentage problems: finding X% of a number, calculating the percentage change between two values, and determining what percentage one number is of another — all in one simple tool.

How to Use This Calculator

1. X% of Y: Enter the percentage and the number to find the portion (e.g., “What is 15% of 85?”)
2. % Change: Enter a starting value and ending value to find the percentage increase or decrease.
3. X is what % of Y: Enter both numbers to find what percentage the first is of the second.

Common Uses

• Discounts: “A $120 item is 25% off — what’s the sale price?” → 25% of 120 = $30 off → $90
• Tax: “Sales tax is 8.5% on a $45 purchase.” → 8.5% of 45 = $3.83 tax
• Grade calculation: “I got 43 out of 50 — what’s my percentage?” → 43 is what % of 50 = 86%
• Tip: “15% tip on a $78 dinner.” → 15% of 78 = $11.70
• Revenue change: “Sales went from $80,000 to $95,000.” → % change = 18.75% increase

Percentage Change Explained

A percentage change measures the relative change between two values. A positive result is an increase; negative is a decrease. Note that percentage changes are not symmetric: a 50% increase followed by a 50% decrease does not return to the original value — it results in a 25% net loss ($100 → $150 → $75).

Frequently Asked Questions

What’s the difference between percentage and percentage points?

If your test score improved from 60% to 75%, it increased by 15 percentage points, but by 25% in percentage terms (15/60 × 100 = 25%). The two terms measure different things and are often confused in news headlines.

How do I calculate a percentage of a percentage?

Multiply the two percentages together (as decimals). For example, 30% of 40% = 0.30 × 0.40 = 0.12 = 12%.