UlvixorPercentage Calculator
Calculate percentages in three different ways: the percentage of a number, what percent one value represents of another, and the percentage change (increase or decrease) between two figures. Everything runs in your browser, instantly.
How it works
- Pick the tab for the type of calculation you need: 'X% of Y', 'X is what % of Y', or '% change from X to Y'.
- Enter the two required numbers in the corresponding fields.
- The result updates automatically as you type, with no button to press.
- If the calculation isn't possible (for example, dividing by zero), you'll see a clear message explaining the issue.
Use cases
- Calculating discounts on purchases: how much 20% off a $50 item comes to.
- Figuring out what percentage of your budget a specific expense represents.
- Calculating the percentage increase or decrease in prices, sales, or any metric between two periods.
- Quickly checking commissions, tips, or taxes without opening a spreadsheet.
Use cases
- Calculating discounts on purchases: how much 20% off a $50 item comes to.
- Figuring out what percentage of your budget a specific expense represents.
- Calculating the percentage increase or decrease in prices, sales, or any metric between two periods.
- Quickly checking commissions, tips, or taxes without opening a spreadsheet.
Common mistakes
- Confusing 'percentage points' with 'percentage change' when comparing two figures that are already percentages, for example a rate that rises from 5% to 8%.That's a 3-percentage-point increase, but a relative change of 60% ((8-5)/5 × 100). The '% Change' tab always calculates the relative change, not the point difference.
- Calculating a percentage increase by subtracting the percentages instead of applying the change formula, for example believing that going from 50 to 75 is '25% more'.It's actually a 50% increase. Use the '% change from X to Y' tab and the tool automatically applies ((final − initial) / initial) × 100.
- Swapping the numerator and denominator when calculating 'what % is X of Y', dividing the total by the part instead of the part by the total.The 'X is what % of Y' tab labels each field separately; check that the partial value goes in 'X' and the total in 'Y' before reading the result.
Frequently asked questions
Multiply the number by the percentage and divide by 100. For example, 20% of 50 is (20 / 100) × 50 = 10.
Divide the value by the total and multiply by 100. For example, 10 is (10 / 50) × 100 = 20% of 50.
Subtract the initial value from the final value, divide by the initial value (in absolute terms), and multiply by 100. A positive result means an increase; a negative one means a decrease.
No. All calculations are performed locally in your browser using JavaScript. No data is sent to or stored on any server.
Alternatives
In Excel or Google Sheets you can do these calculations with formulas like =B1/B2*100 or =(B2-B1)/B1*100, but you have to remember which one applies to each case. This calculator skips that step: you pick the calculation type, type in the two values, and see the result instantly, with no spreadsheet to open or formulas to memorize.