Percentage Calculator
Calculate percentages, percentage change, and percentage of totals.
Private ● Runs entirely in your browser Your text never leaves your device.No account required.No data uploaded.Nothing stored unless you choose to save it.Add to Home Screen
Install Percentage Calculator so it opens like an app and works offline.
- Open Chrome’s menu (⋮, top-right).
- Tap Install app or Add to Home screen.
- Confirm — the icon appears on your home screen.
- Tap the Share button in Safari’s toolbar.
- Choose Add to Home Screen.
- Tap Add.
Enter values to calculate.
Common Questions
What is a percentage?
A percentage is a number expressed as a fraction of 100. The word comes from the Latin "per centum," meaning "per hundred." When you say 25%, you mean 25 out of every 100, or one quarter. Percentages make it easy to compare quantities of different sizes on a common scale.
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 20% of 150 = (20 × 150) ÷ 100 = 30. A quicker mental shortcut: move the decimal one place left to get 10% (150 → 15), then double it to get 20% (15 × 2 = 30). This tool calculates it instantly.
How do I calculate what percentage one number is of another?
Divide the part by the whole, then multiply by 100. For example, to find what percentage 45 is of 200: (45 ÷ 200) × 100 = 22.5%. This is useful for grading, survey results, and measuring progress toward a goal.
What is the difference between percentage and percentage points?
A percentage point is the arithmetic difference between two percentages. If interest rates rise from 3% to 5%, that is a 2 percentage point increase, but it is also a 66.7% increase in the rate itself. Confusing the two is a common mistake. "Percentage points" are used when comparing two percentages directly; "percent change" is used when measuring relative change.
How do I calculate percentage increase or decrease?
Subtract the original value from the new value, divide by the original value, then multiply by 100. Formula: ((New − Old) ÷ Old) × 100. If a price goes from £80 to £100: ((100 − 80) ÷ 80) × 100 = 25% increase. A negative result means a decrease.
How do I calculate a discount?
Multiply the original price by the discount percentage and divide by 100 to get the discount amount, then subtract from the original price. For a 30% discount on $120: discount = (30 × 120) ÷ 100 = $36; final price = $120 − $36 = $84. Alternatively, multiply by (1 − 0.30) = 0.70 to get $84 directly.
Why does 50% off followed by 50% on not equal the original price?
Because each percentage is applied to a different base. A $100 item at 50% off becomes $50. Adding 50% back onto $50 gives $75, not $100. The second operation uses the reduced price as its base, so the two changes do not cancel out. This is why percentage changes are not symmetric.
How do I calculate tax from a percentage?
Multiply the pre-tax price by the tax rate and divide by 100. For 20% VAT on £60: tax = (20 × 60) ÷ 100 = £12; total = £60 + £12 = £72. To find the pre-tax price from an already-taxed total, divide by (1 + tax rate / 100). For a £72 total with 20% VAT: £72 ÷ 1.20 = £60.