Percentage Calculator
Find what percentage one number is of another, instantly. Useful for discounts, grades, tips, and everyday math.
How to use the Percentage Calculator
Enter the percentage value in the first box and the total number in the second box, then click "% of value." The tool instantly calculates what that percentage of the number equals — for example, 20% of 200 equals 40.
Common uses for percentage calculations
Percentages come up constantly in everyday life: figuring out a discount at checkout, calculating a tip at a restaurant, working out exam or grade percentages, understanding interest rates, or comparing statistics. Doing this math by hand is easy to get wrong, especially under time pressure — this calculator gives you an instant, accurate answer every time.
Frequently asked questions
How do I calculate a discount using this tool?
Enter the discount percentage in the first box and the original price in the second box. The result shows the discount amount — subtract it from the original price to get the final price. For a dedicated tool that does this in one step, try the Discount Calculator.
What's the formula behind this calculator?
The tool uses the standard percentage formula: (percentage ÷ 100) × total number = result. For example, 20% of 200 is calculated as (20 ÷ 100) × 200 = 40.
Can I calculate percentage increase or decrease between two numbers?
This calculator finds what a percentage of a number equals. For percentage change between two values, subtract the smaller from the larger, divide by the original number, and multiply by 100.
Is my data stored anywhere?
No. This tool is part of the Toolyard collection of free, browser-based utilities. All calculations run locally in your browser — nothing you enter is uploaded to a server or stored anywhere.
The three questions percentage problems usually boil down to
Most real-world percentage questions fall into one of three types: finding what percentage one number is of another (what % is 45 of 60?), finding a percentage of a number (what is 15% of 200?), or finding the percentage change between two numbers (a price went from $80 to $100 — what's the percentage increase?). Each uses a slightly different formula, which is a common source of confusion when doing the math by hand under time pressure.
Percentage change trips people up the most
Percentage increase and percentage decrease aren't symmetrical the way people intuitively expect — going from 100 to 150 is a 50% increase, but going back from 150 to 100 isn't a 50% decrease, it's a 33.3% decrease, because percentage change is always calculated relative to the starting number, not a fixed midpoint. This asymmetry matters in contexts like stock returns, discounts followed by markups, and salary changes.
Common uses
Calculating sale discounts, figuring out grade or test score percentages, determining salary raises or pay cuts accurately, and computing statistics like conversion rates or growth rates are all everyday situations where getting the right percentage formula — not just any percentage formula — matters.