- Choose one of the three modes, depending on what you are solving for:
- What is X% of Y? — find a percentage of a total.
- X is what percent of Y? — find the percentage one value represents of another.
- Y is X% of what number? — find the total when you know an amount and its percentage.
- Enter the values shown and the tool returns the result instantly.
All calculations run locally in your browser — no numbers are uploaded, so you can work with personal budgets, grades and business figures privately.
The three modes cover the most common percentage questions people meet daily: applying a percentage, comparing a part to a whole, and reversing a percentage to find a base amount.
Tips
Pick the mode that matches the question you are answering. For a discount, “What is X% of Y?” tells you the amount off. For a grade, “X is what percent of Y?” shows the fraction as a percentage. For growth or reverse calculations, the third mode recovers the original total.
Double-check which number is the total versus the part — swapping them is the most common mistake. When you see the result, quickly estimate whether it makes sense; a percentage should never move in the wrong direction from your input.
Why use it
Percentages appear everywhere — taxes, tips, discounts, grades, savings interest and growth rates. Working them out by hand is error-prone, and rounding in the wrong place changes the answer. This calculator is instant, free and private, running entirely in your browser with no install and no upload.