Percentages are the language of everyday math — from shopping discounts and salary raises to exam scores and tax calculations. This free percentage calculator covers 6 common modes so you never have to fumble with a formula again. Whether you need a quick discount check or want to verify a percent change, you'll get an instant, accurate result.
How the Percentage Calculator Works
Each of the 6 modes targets a distinct calculation. Mode 1 finds X% of a number (ideal for tips and taxes). Mode 2 answers "X is what percent of Y?" (perfect for test scores). Mode 3 computes percent change between two values (great for price or salary comparisons). Mode 4 adds a percentage (e.g., price + VAT). Mode 5 applies a discount. Mode 6 reverse-engineers the original value before a percentage change was applied. Enter your numbers in the relevant row and tap the button — no page reload needed.
3 Real-World Examples
Item costs $89.99, it's 30% off. 89.99 × 0.30 = $27.00 discount → you pay $62.99. Always verify "sale" prices with this — a 40% off sticker then 20% at checkout is NOT 60% off (it's 52%).
Current salary $55,000, you got a 7% raise. 55,000 × 0.07 = $3,850 increase → new salary $58,850. Use the percent change mode to verify: (58,850 − 55,000) ÷ 55,000 × 100 = 7%.
You got 47 out of 60 questions right. 47 ÷ 60 × 100 = 78.3%. Need to pass with 75%? You cleared it. Need an A (90%)? You need 54 correct out of 60.
Tips
- To find 10% of any number instantly, just move the decimal one place to the left — then scale up or down from there.
- Stacked discounts are never additive: 40% off then 20% off equals 52% off total, not 60%.
- When comparing percent changes, watch for asymmetry — a 50% loss requires a 100% gain just to break even.
- Use Mode 6 to reverse-engineer pre-tax or pre-markup prices when you only see the final amount.
Understanding Percent vs. Percentage Points
These two phrases sound similar but mean very different things. A "percentage point" change is absolute: going from 4% to 6% is a 2 percentage point increase. A "percent" change is relative: that same move is a 50% increase (2 ÷ 4 × 100). In finance and policy reporting, the distinction is critical — misreading it can lead to very wrong conclusions about interest rates, tax brackets, or investment returns.