Percentage Calculator
Solve any percentage problem in seconds — what percent, increase/decrease, or add/subtract a percentage.
How to Calculate Percentages
A percentage is a fraction of 100 — "per cent" literally means "per hundred." The core formula behind every percentage calculation is: part ÷ whole × 100 = percentage. This one relationship, rearranged, solves every common percentage problem: finding a percentage of a number, working out what percentage one number is of another, calculating percentage change, or adjusting a number by a percentage.
The Four Calculators Explained
X% of Y answers questions like "what is 15% of 200?" — used constantly for discounts, tax and commission. The formula is (X ÷ 100) × Y. X is what % of Y flips the question around: "30 is what percent of 200?" — useful for test scores, budget shares, and completion rates. The formula is (X ÷ Y) × 100. Percentage increase/decrease tells you how much something changed in relative terms, using ((New − Old) ÷ Old) × 100 — essential for tracking price changes, salary raises, or performance metrics. Add/subtract a percentage applies a percentage change to a starting number, such as adding 20% VAT or applying a 15% discount.
Worked Examples
Sale price. A jacket costs €120 and is reduced by 30%. 30% of 120 is (30 ÷ 100) × 120 = €36, so the sale price is 120 − 36 = €84. In the Add / Subtract tab, enter 120 and −30 to get the same answer in one step.
VAT. A price of €80 before tax with 25.5% VAT (the standard rate in Finland since September 2024) becomes 80 × 1.255 = €100.40. To remove VAT from a price that already includes it, divide instead of subtracting: €100.40 ÷ 1.255 = €80. Subtracting 25.5% from €100.40 would give the wrong answer, €74.80.
Salary rise. A monthly salary rises from €3,200 to €3,360. The change is (3,360 − 3,200) ÷ 3,200 × 100 = 5%.
Share of a budget. If €450 of a €2,500 monthly budget goes on food, food is 450 ÷ 2,500 × 100 = 18% of the budget.
Percentages and Investing
Percentages are how investors compare results. A share that rises from €20 to €25 has gained 25%, but a share that falls 50% needs to rise 100% to get back to where it started. This asymmetry is one reason value investors care so much about avoiding large losses: the deeper the fall, the harder the climb back. You can see how steady percentage returns build over time in the Compound Interest Calculator.
| Loss | Gain needed to recover |
|---|---|
| 10% | 11.1% |
| 25% | 33.3% |
| 50% | 100% |
| 75% | 300% |
Frequently Asked Questions
Why is percentage change calculated from the "old" value?
Percentage change is always relative to the starting point, because that reflects the actual proportional change experienced. A price rising from €80 to €100 is a 25% increase, but if it then fell back from €100 to €80, that would be a 20% decrease — not 25% — because the base changed. This asymmetry surprises many people the first time they encounter it.
What's the difference between percentage points and percent?
If an interest rate rises from 5% to 7%, that is a 2 percentage point increase, but a 40% relative increase (2 ÷ 5 × 100). Percentage points measure the raw difference between two percentages; percent measures the relative change. Mixing these up is a common source of confusion in financial and statistical reporting.
How do I calculate a percentage discount at checkout?
Use the Add / Subtract tab with a negative percentage. For a 20% discount on a €50 item, enter 50 as the number and −20 as the percentage. The result, €40, is the price you pay.
How do I remove VAT from a price?
Divide the price by 1 plus the VAT rate. With 25.5% VAT, a price of €125.50 including tax is €125.50 ÷ 1.255 = €100 before tax.