Switch between the three most common percentage questions: what is X% of Y, X is what percent of Y, and the percentage change between two numbers. Pick a mode and the right inputs appear.
Every answer comes with the step-by-step formula used to reach it, so you can check the math or learn how percentages work rather than just copying a number.
The result updates live as you type — no submit button. Try different values and watch the answer and formula change immediately.
All math runs in your browser with no server calls. Nothing you type is uploaded, and the tool works offline once the page has loaded.
Divide the percentage by 100 and multiply by the number. For example, 25% of 200 = (25 ÷ 100) × 200 = 0.25 × 200 = 50. Use the "X% of Y" mode and the calculator does this for you.
Divide the part by the total and multiply by 100. For example, 30 out of 150 is (30 ÷ 150) × 100 = 20%. Use the "X is what % of Y" mode.
Subtract the old value from the new value, divide by the absolute value of the old value, then multiply by 100: ((new − old) ÷ |old|) × 100. Going from 100 to 150 is a +50% increase; 150 to 100 is a −33.33% decrease.
A change from 10% to 15% is a 5 percentage-point rise, but a 50% relative increase. This tool reports relative percentage change; keep the distinction in mind when comparing rates.
No. The entire calculation runs locally in your browser with no server calls. Nothing you type is uploaded, so the tool is private and works offline once the page has loaded.
This percentage calculator is provided for general informational and educational purposes. Results are rounded for display. Verify critical figures independently before relying on them.