What Is This Percentage Calculator?

This free online percentage calculator helps you solve the three most common percentage problems instantly — no manual math needed. Find what a percentage of a number is, work out what percentage one number is of another, or calculate the percentage increase or decrease between two values.

How to Use “X% of Y”

1. Select “X% of Y” mode at the top of the calculator (this is the default view).
2. Enter the Percentage you want to find, e.g. 20.
3. Enter the Number you want to apply it to, e.g. 500.
4. Click “Calculate.”
5. Your result appears instantly, showing the exact value.

How to Use “X is what % of Y”

1. Switch to “X is what % of Y” mode using the toggle at the top.
2. Enter the Value (X) — the number you have.
3. Enter the Total (Y) — the number you’re comparing it against.
4. Click “Calculate.”
5. The result shows exactly what percentage X represents of Y.

How to Use “% Increase/Decrease”

1. Switch to “% Increase/Decrease” mode using the toggle.
2. Enter the From Value — the original/starting number.
3. Enter the To Value — the new/final number.
4. Click “Calculate.”
5. The result shows the percentage change, the exact difference, and whether it’s an increase or decrease.

Why Use an Online Percentage Calculator?

• Quick everyday math — calculate discounts, tips, taxes, or grades in seconds.
• Business and finance — work out profit margins, growth rates, or budget changes accurately.
• Avoid manual errors — percentage math is easy to get wrong by hand; this tool handles it automatically.
• Works worldwide — plain numbers, no currency or unit conversion needed.
• Completely free, no signup required — use it as many times as you need.

Frequently Asked Questions

How do I find what percentage one number is of another?

Switch to “X is what % of Y” mode, enter your value and the total, then click calculate. The tool instantly shows the percentage.

Can this calculator show percentage increase or decrease?

Yes. Use the “% Increase/Decrease” mode, enter the original and new values, and the tool will show the percentage change along with the direction.

Can I calculate a percentage of a negative number?

Yes, all three modes accept negative numbers and will calculate the correct result.

Is this percentage calculator free to use?

Yes, it’s completely free with no registration, downloads, or hidden charges — just enter your numbers and get instant results.