Percentage Calculator
Calculate percentages five different ways instantly.
How to Use the Percentage Calculator
This calculator provides five different percentage calculation modes, covering the most common real-world percentage problems. All calculations update instantly as you type — no button pressing needed.
Mode 1: X% of Y
Find a percentage of a number. Example: "What is 15% of 200?" → 30. Used for calculating tips, discounts, tax amounts, commission, and any situation where you need a fraction of a total.
Mode 2: X is what % of Y?
Find what percentage one number is of another. Example: "30 is what percent of 200?" → 15%. Used for calculating test scores (you got 45 out of 60 — what grade is that?), market share, survey results, and relative proportions.
Mode 3: Percentage Change
Calculate the percentage increase or decrease from one value to another. Example: "Price went from $80 to $100 — what % increase is that?" → 25%. The result is shown with a + (increase) or − (decrease) prefix. Used for tracking price changes, population growth, revenue changes, and comparing before/after values.
Mode 4 & 5: Add or Subtract a Percentage
Mode 4 adds a percentage to a value (e.g., add 8% tax to a $50 item = $54). Mode 5 subtracts (e.g., take 20% off $120 = $96). These are useful for quick discount and tax calculations in shopping, pricing, and financial analysis.
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Frequently Asked Questions
How do I calculate a 20% discount?
Use Mode 5 (Subtract X% from Y). Enter the original price in the "value" field and 20 in the "%" field. The result shows the discounted price. Alternatively, use Mode 1 to find what 20% of the price is (the discount amount), then subtract it manually. For example, 20% of $150 = $30; $150 − $30 = $120.
How is percentage change calculated?
Percentage change = ((New Value − Old Value) / |Old Value|) × 100. If the result is positive, it's an increase; if negative, it's a decrease. Example: from 80 to 100, the change is (100−80)/80 × 100 = 25% increase. From 100 to 80, the change is (80−100)/100 × 100 = −20% decrease. Note that a 25% increase followed by a 20% decrease does NOT return to the original value.
What's the difference between "percent of" and "percent off"?
"X% of Y" gives you the portion (e.g., 10% of 100 = 10). "X% off Y" means you subtract that portion from the original (e.g., 10% off 100 = 100 − 10 = 90). So "20% of $50" = $10, while "20% off $50" = $40. This is a common source of confusion when shopping for discounts.
How do I calculate a tip?
Use Mode 1 (X% of Y). Enter the tip percentage (e.g., 18) and the bill amount (e.g., 65). The result is your tip amount (11.70). Add that to the bill for the total. Or use our dedicated Tip Calculator, which also splits the bill between multiple people and rounds up per person.
Can I calculate a percentage of a percentage?
Yes — run two calculations. For example, "30% of 40% of 500": First calculate 40% of 500 = 200 (Mode 1). Then calculate 30% of 200 = 60 (Mode 1 again). Alternatively, multiply the percentages: 0.30 × 0.40 = 0.12 = 12%, then calculate 12% of 500 = 60.