Result
30
Result
30%
Percentage change
+25%
Add — after increase / markup
230
Subtract — after discount
170
Discounts, marks, tips and growth — answered instantly, with the working shown.
Result
30
Result
30%
Percentage change
+25%
Add — after increase / markup
230
Subtract — after discount
170
Three steps, no formulas to memorise.
Choose one of the four tabs — percent of a number, what percent, percentage change, or add / subtract a percent.
Enter the values you know. The answer updates live as you type — there is no calculate button to press.
Every result shows the formula with your own numbers filled in, so you can check it or reuse it anywhere.
Quick answers about percentages and this tool.
Multiply the number by the percentage, then divide by 100. For example, 20% of 150 is (20 ÷ 100) × 150 = 30. The first tab does exactly this and shows the working with your numbers.
Divide the part by the total and multiply by 100. If you scored 45 out of 150, that is (45 ÷ 150) × 100 = 30%. Use the “What percent?” tab — note the total cannot be zero, because dividing by zero has no answer.
Subtract the old value from the new value, divide by the old value, and multiply by 100. A rise from 80 to 100 is (100 − 80) ÷ 80 × 100 = +25%. A negative result means the value went down. A percentage change from 0 cannot be calculated, since the starting value is the divisor.
Use the “Add / Subtract %” tab and read the subtract box: it takes the percentage off the amount for you. A 15% discount on 200 leaves 170 — the same tab also shows the add box, handy for tax, tips, and markups.
Yes. This calculator runs entirely in your browser — your numbers are never uploaded, saved, or sent anywhere. There is no account and no tracking of what you type.