Percentage Calculator
Every percentage problem solved live — with the working shown, not just the answer.
Four percentage calculators on one page, each solving as you type: what is X% of Y, X is what percent of Y, the percent change between two numbers, and increasing or decreasing a number by a percentage. Every answer shows the formula with your numbers substituted in — so you see how it was calculated, not just the result.
Use it to work out a 15% tip, a 20% discount, VAT on an invoice, a raise or price increase, exam scores, or how much a stock moved. Because the working is shown step by step, it doubles as a homework checker — you can copy the method, not just the number.
How to calculate a percentage
- 1
Pick the card that matches your question — e.g. "What is X% of Y?" for a discount or tip.
- 2
Type your two numbers; the answer appears instantly with the formula written out.
- 3
Copy the result, or read the working to see exactly how it was computed.
Why use Nofolo’s percentage calculator?
Four calculators in one
% of a number, X as a % of Y, percent change, and increase/decrease by % — side by side.
Shows the working
Each result displays the formula with your numbers plugged in, e.g. 25 × 80 ÷ 100 = 20.
Live results
Answers update on every keystroke — no calculate button, no page reload.
Increase and decrease labeled
Percent change tells you clearly whether it is an increase or a decrease, with the sign handled for you.
Handles edge cases gracefully
Divide-by-zero and empty inputs get a gentle hint instead of NaN or a cryptic error.
Free and private
No signup, no limits — all math happens in your browser.
Frequently asked questions
How do I calculate the percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 25% of 80 is 25 × 80 ÷ 100 = 20. The first card does this live and shows that exact working with your numbers.
How do I work out what percent X is of Y?
Divide X by Y and multiply by 100. For example, 30 is 30 ÷ 120 × 100 = 25% of 120. Use the second card — it also catches the common mistake of dividing the numbers the wrong way round.
How is percentage change calculated?
Percent change = (new − old) ÷ old × 100. Going from 50 to 65 is (65 − 50) ÷ 50 × 100 = a 30% increase. The calculator labels the result as an increase or decrease automatically.
What is the difference between percentage change and percentage points?
If a rate moves from 10% to 15%, it rose 5 percentage points but 50 percent (5 ÷ 10 × 100). Use the percent-change card when comparing two values, and plain subtraction when comparing two percentages.
How do I add or subtract a percentage, like VAT or a discount?
Use the increase/decrease card: it computes Y ± (Y × X ÷ 100). Adding 7.5% VAT to 2,000 gives 2,000 + (2,000 × 7.5 ÷ 100) = 2,150; a 20% discount on 50 gives 40.
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