Percentage Calculator
Solve everyday percentage questions in four modes — no formulas to remember.
Percentage Calculator
🔒 Nothing you enter is sent anywhere or stored. All processing happens in your browser.
Features
Four calculators in one
Handles the four everyday percentage questions — X% of Y, X is what % of Y, percentage increase and percentage decrease — so you never have to recall which formula fits.
Instant, plain answers
Enter two numbers and read the result immediately, with no rounding surprises.
Copy the result
Copy the answer to your clipboard to drop it into a message, sheet or document.
Works on any device
Runs entirely in your browser, so it's ready on a phone at the shops or a laptop at your desk.
How it works — in four simple steps
No signup, nothing to install — it all runs in your browser.
Pick the question type
Choose the mode that matches what you're solving: X% of Y, X is what % of Y, % increase, or % decrease.
Enter your two numbers
Type the percentage and value, or the two values, depending on the mode.
Read the answer
The result updates as you type — no button-hunting required.
Copy if you need it
Press Copy result to reuse the figure elsewhere.
How it works
Percentages express a part of a whole out of 100, but the same word covers several different questions. This calculator handles the four most common ones so you don't have to remember which formula applies.
X% of Y answers "what is 20% of 150?" by computing X ÷ 100 × Y. X is what % of Y reverses that — it tells you what proportion one number is of another, using X ÷ Y × 100, perfect for working out a score or a share. Percentage increase and percentage decrease compare an original value to a new one and report how much it changed relative to the starting point, using (new − old) ÷ old × 100.
The distinction between increase and decrease matters: a change is always measured against the original figure, so a rise from 40 to 50 is a 25% increase, while a fall from 50 to 40 is a 20% decrease — the same 10-unit gap gives different percentages because the baselines differ. Results update as you type, and you can copy any answer with one click.
Examples
When to use it
Work out a discount
Find what 30% off a price actually saves you, or what you'll pay after the reduction.
Check a tip or share
Calculate a percentage of a bill to split or tip fairly.
Measure a change
See the percentage increase or decrease between two figures, like last month's and this month's sales.
Understand a statistic
Turn "45 out of 60" into a percentage to compare scores or results at a glance.
Tips for the best results
- Match the mode to the words. "What is X% of Y" and "X is what % of Y" are different questions — pick the mode that mirrors how yours is phrased.
- Increase vs decrease matters. A 20% rise then a 20% fall doesn't return to the start; use the right mode for each step.
- Copy to avoid retyping. Use Copy result when the figure feeds into another calculation so you don't introduce a typo.
Percentage of two numbers — worked examples
The most common real question is "what percentage of two numbers is X" — i.e. what percent one number is of another. Here are quick worked examples using the same method the calculator applies:
| Question | Method | Answer |
|---|---|---|
| 45 is what % of 60? | 45 ÷ 60 × 100 | 75% |
| 18 is what % of 24? | 18 ÷ 24 × 100 | 75% |
| 12 is what % of 200? | 12 ÷ 200 × 100 | 6% |
| What is 20% of 150? | 20 ÷ 100 × 150 | 30 |
| 30 → 45 (increase) | (45 − 30) ÷ 30 × 100 | 50% up |
Rule of thumb: "of" means multiply, "is what %" means divide the part by the whole. Pick the matching mode above and enter your two numbers.