Percentage Calculator
Calculate percentages, increases and differences
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Percentages show up in nearly every financial and shopping decision, yet the three questions people ask are constantly confused with each other: "what is 20% of 450?", "what percent is 45 of 450?", and "what is the percentage increase from 400 to 450?" They have different formulas, and mixing them up is why sale discounts, tips, tax calculations and statistics so often get miscomputed on a phone calculator.
This free percentage calculator separates all three modes explicitly, so you pick the question rather than remembering the formula. Percentage change — new minus old, divided by old, times 100 — handles raises, discounts and price swings; the 'X% of Y' mode handles tips and tax; and the ratio mode answers what percent one number is of another. Results appear instantly with the worked explanation shown, which makes it useful both for getting the number and for double-checking the math behind homework or a report.
Why use Percentage Calculator
Working out sale discounts
A 35% discount on an $89 item is instant — and you can verify the store's 'final price' claim before paying.
Calculating tips and tax
Splitting a restaurant bill with an 18% tip and local sales tax takes seconds with the 'X% of Y' mode.
Tracking growth and change
Revenue up from $12,400 to $15,100, or weight down from 90 to 84 kg — percentage change mode quantifies the shift.
Checking grades and statistics
Scoring 41 out of 48 on an exam is 85.4% — the ratio mode computes it directly for tests, surveys and KPIs.
Pro tips
- Percentage increase and decrease are asymmetric: a 50% loss needs a 100% gain to break even — use change mode in both directions to see why.
- To add a percentage (e.g. 20% VAT), multiply by 1.2; to find the pre-tax price, divide by 1.2 — don't subtract 20%, it gives the wrong answer.
- 'Percentage points' and 'percent' differ: an interest rate moving from 3% to 4% rose by 1 point but by 33%.
- During multi-discount sales, percentages don't add: 50% + 20% off is 60% off total (0.5 × 0.8), not 70%.
How to use Percentage Calculator
- 1Choose a calculation type
- 2Enter the numbers
- 3Read the instant result with explanation
Frequently Asked Questions
How do I calculate percentage increase?▾
New minus old, divided by old, times 100. Our 'percentage change' mode does this automatically.
Can I calculate what percent A is of B?▾
Yes — the third mode computes A ÷ B × 100 for you.