Money
Percentage Calculator
Instantly calculate "what is X% of Y", "what percent is A of B", "increase by X%", and "decrease by X%". Useful for discounts, tax, interest, and more.
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Discount Amount Quick Reference (%OFF)
| Original Price | 5%OFF | 10%OFF | 15%OFF | 20%OFF | 25%OFF | 30%OFF | 50%OFF |
|---|---|---|---|---|---|---|---|
| 1,000 | 950 | 900 | 850 | 800 | 750 | 700 | 500 |
| 2,000 | 1,900 | 1,800 | 1,700 | 1,600 | 1,500 | 1,400 | 1,000 |
| 3,000 | 2,850 | 2,700 | 2,550 | 2,400 | 2,250 | 2,100 | 1,500 |
| 5,000 | 4,750 | 4,500 | 4,250 | 4,000 | 3,750 | 3,500 | 2,500 |
| 10,000 | 9,500 | 9,000 | 8,500 | 8,000 | 7,500 | 7,000 | 5,000 |
| 20,000 | 19,000 | 18,000 | 17,000 | 16,000 | 15,000 | 14,000 | 10,000 |
| 30,000 | 28,500 | 27,000 | 25,500 | 24,000 | 22,500 | 21,000 | 15,000 |
| 50,000 | 47,500 | 45,000 | 42,500 | 40,000 | 37,500 | 35,000 | 25,000 |
| 100,000 | 95,000 | 90,000 | 85,000 | 80,000 | 75,000 | 70,000 | 50,000 |
Formula: Discounted price = Original price × (1 − discount rate). Example: 10,000 × (1 − 0.20) = 8,000 (20% off).
Tips
- To find what percent A is of B: A ÷ B × 100. Example: 30 is what percent of 120? → 30 ÷ 120 × 100 = 25%.
- "Increase by X%" means value × (1 + X/100). Adding 10% sales tax on 10,000 → 10,000 × 1.1 = 11,000.
- "Decrease by X%" means value × (1 − X/100). A 20% discount on 10,000 → 10,000 × 0.8 = 8,000.
- Stacking discounts: a 20% discount followed by an additional 10% off is not 30% off — it's 28% off (0.8 × 0.9 = 0.72 of original).
- The same formula works for interest rates. A principal of 10,000 at 3% annual interest for one year yields 10,000 × 1.03 = 10,300.
Frequently Asked Questions
Side Note — Why "percent" and "percentage points" are different
When a news headline says "interest rates rose by 1%," it's easy to assume they mean a 1% relative increase. But in practice, this often means 1 percentage point — an absolute change from, say, 2% to 3%. That's a 50% relative increase, not 1%. Journalists mix up these terms regularly, which can mislead readers about the true magnitude of changes.
The word "percent" comes from the Latin per centum, meaning "per hundred." The % symbol itself likely evolved from a scribal shorthand for "p. cento" compressed over centuries of handwriting into "pc" → "%" — a typographic fossil from Renaissance commercial manuscripts.
Percentage calculations appear everywhere: store discounts, nutrition labels, election results, financial returns, and scientific measurements. Mastering the three basic operations — finding a percent of a value, finding what percent one number is of another, and calculating percent change — covers the vast majority of real-world needs.