Calculate Percentages

Every Percentage Calculation on One Page

Most percentage calculators make you pick the right formula first, then plug numbers into a single box. This one lays out every common percent job as its own labeled row — what is X% of Y, what percent one number is of another, percent increase or decrease, adding or subtracting a percent, percent difference, and the reverse ("30 is 25% of what?"). Fill in the blanks and the answer appears instantly, with a plain-English sentence you can copy.

It runs entirely in your browser with native math — no signup, no ads reloading between clicks, nothing sent to a server. Because each row is independent, you can keep one answer on screen while you work through another.

One honest note: results are rounded to four decimal places for display, so a repeating value like "1 is 33.3333% of 3" is shown to that precision rather than to infinity.

Common Uses

• Tips and discounts: Add 18% to a bill or take 25% off a price and see the new total right away.
• Sales and growth: Work out the percent increase from last month's number to this month's, or how far a metric fell.
• Grades and scores: Turn "45 out of 180" into a percentage without hunting for the formula.
• Tax and markup: Add a sales-tax or markup percent to a base figure, or back out the original number from a total.
• Comparing two numbers: Use percent difference to compare two measurements when neither one is the "correct" baseline.
• Reverse math: Know a deposit is 25% of the price? Find the full price in a single step.

Privacy: Every calculation runs entirely in your browser. Nothing you type is sent anywhere, logged, or stored.