Percentage Calculator — 3 Most-Needed Calculations
Three percentage questions cover almost every real situation — discounts, marks, tax, raises, statistics. Pick the one you need, enter two numbers, done. Each mode shows the formula used, so you can also learn to do it in your head.
How to use this tool
- Pick the question type — the input labels change to guide you.
- What is X% of Y: for discounts, tips, tax — e.g. 15% of 200 = 30.
- X is what % of Y: for scores and shares — e.g. 45 out of 60 = 75%.
- % change: for raises and price moves — e.g. from 250 to 300 = +20%.
Frequently asked questions
How do I calculate a percentage discount quickly in my head?
Find 10% first (move the decimal one place left), then scale. For 30% off 450: 10% is 45, so 30% is 135, price becomes 315. For 15%: take 10% + half of it.
What's the difference between percentage change and percentage points?
If interest rises from 4% to 6%, that's an increase of 2 percentage points but a 50% relative increase. News headlines often mix these up — this calculator's % change mode gives the relative change.
Why is a 50% loss not fixed by a 50% gain?
Because the base changes. Drop 100 → 50 is −50%; recovering 50 → 100 requires +100%. The bigger the loss, the disproportionately bigger the gain needed — a key investing insight.
How do I add a percentage on top (like tax)?
Multiply by (1 + rate). Adding 18% tax to 1,200: 1,200 × 1.18 = 1,416. To remove tax from a gross figure, divide by 1.18 instead — don't subtract 18%, that gives the wrong answer.
How do I calculate my exam percentage?
Use mode 2: your marks are the part (X), total marks are the whole (Y). 432 out of 550 → (432 ÷ 550) × 100 = 78.5%.