% Percentage Calculator

Five calculators in one. Solve any percentage problem instantly — tips, discounts, percent change, and more.

Example: What is 20% of 150?

Percentage (%)

Of this number

20% of 150

Formula(20 ÷ 100) × 150

Half that15

Double that60

💡 Percentages in Real Life

Tips: Use “Add %” with 15–20% on restaurant bills.
Sales: Use “Subtract %” to see the real savings on a discount.
Raises / growth: Use “% Change” to compare before and after.
Grades & stats: Use “X is what % of Y” to turn scores into percentages.

How This Tool Works

Percentages are one of the most commonly used mathematical concepts in daily life — from calculating tips and taxes to understanding discounts, pay raises, and investment returns. This calculator supports five modes: finding a percentage of a number, determining what percentage one number is of another, calculating percentage change between two values, adding a percentage (for tips/tax), and subtracting a percentage (for discounts). Each mode shows the formula and a detailed breakdown so you understand the math, not just the answer.

Formula / Methodology

Basic: X% of Y = (X/100) × Y · % Change: ((New − Old) / Old) × 100 · What %: (Part / Whole) × 100

💡 Tips & Best Practices

1Percentage math is commutative: 8% of 50 equals 50% of 8 — both are 4. Use this shortcut for quick mental math.
2When tipping, calculate 10% (move the decimal) then adjust: 15% = 10% + half of 10%, 20% = 10% × 2.
3To reverse a percentage increase: if something is $120 after a 20% markup, the original was $120 ÷ 1.20 = $100 — not $120 minus 20%.
4Percentage points and percentages are different: going from 10% to 12% is a 2 percentage point increase but a 20% relative increase.

Frequently Asked Questions

What is the difference between percent and percentage points?

Percent expresses a proportional relationship. "Percentage points" describe the arithmetic difference between two percentages. If unemployment rises from 5% to 7%, that is 2 percentage points — but a 40% relative increase.

How do I calculate a discount?

Multiply the original price by the discount percentage, then subtract. Example: 25% off $80 → $80 × 0.25 = $20 discount → pay $60. Or multiply by (1 − 0.25) = 0.75 directly.