Quickly calculate percentages, add or subtract percentages from numbers.
Find a percent of a number, add a percentage, or subtract one — instantly and accurately.
Our percentage calculator handles the three percentage calculations people need most often — finding what percent of a number equals, adding a percentage on top of a number, and subtracting a percentage from a number — all in one simple tool with a running calculation history. No mental math, no remembering which way to move the decimal point.
A percentage calculator is an online tool that performs percentage-based math instantly, covering the handful of calculation types that come up constantly in everyday life: finding a percentage of a number, increasing a number by a percentage, and decreasing a number by a percentage.
While the underlying math isn't complicated — percentages are just a way of expressing a fraction out of 100 — doing it reliably in your head, especially with numbers that don't divide evenly, is where mistakes creep in. A calculator removes that risk entirely.
This tool offers three dedicated modes: % of (find what a percentage of a number equals), +% (add a percentage on top of a number), and -% (subtract a percentage from a number) — covering the most common real-world percentage questions without requiring you to remember separate formulas for each.
Percentages show up constantly in shopping, finance, cooking, statistics, and everyday decision-making, which is why a fast, reliable percentage calculator is one of the more frequently reached-for tools online.
Our free percentage calculator provides a quick, accurate way to handle these calculations without doing manual math or opening a spreadsheet. Simply enter your numbers, choose a mode, and get your result instantly.
Instantly find what a given percentage of a number equals.
Increase a starting number by a percentage in one step.
Reduce a starting number by a percentage in one step.
Revisit your last 10 percentage calculations at any time.
All calculations happen locally in your browser, never on a server.
Type in the starting number for your calculation.
Select "% of", "+%", or "-%" depending on what you need.
Type the percentage value you want to apply.
Press equals to see your result instantly.
Get an accurate percentage calculation in a fraction of a second.
Your numbers never leave your browser or get uploaded anywhere.
Calculate as many percentages as you need, with no limits.
Quickly work out the sale price after a percentage-off discount.
Add a tip percentage or a tax rate to a bill instantly.
Calculate what percentage a score represents out of a total.
Simple percentages like 10% or 50% are easy enough to work out in your head, but the moment the numbers get less round — say, 17.5% of 843 — mental math becomes slow and error-prone, especially under time pressure like at a checkout counter or during a meeting.
A percentage calculator online removes that friction entirely, applying the exact formula instantly regardless of how awkward the numbers are.
Mental math also tends to break down specifically around the "add a percentage" and "subtract a percentage" operations, since it's easy to accidentally calculate the wrong base amount or forget whether you're adding to or subtracting from the original number.
For anything beyond the simplest round-number percentages, a free percentage calculator is faster and far less prone to error than working it out by hand.
Percentages appear constantly in daily decisions — discounts, tips, interest rates, grades, statistics — and having a fast, reliable way to calculate them removes a small but recurring source of friction.
One of the biggest benefits of a percentage calculator online is accuracy. There's no risk of a decimal-point slip or a mental math shortcut going wrong, since the calculation is always applied precisely.
Having dedicated modes for "percent of," "add percent," and "subtract percent" also removes the need to remember which formula applies to which situation — you simply pick the mode that matches what you're trying to do.
Keeping a history of past calculations is also useful when working through multiple related percentage questions in a row, letting you glance back at an earlier result without redoing the math.
Because the calculation happens instantly in your browser, there's also no delay or need for an internet connection once the page has loaded, making it a dependable quick-reference tool.
A wide range of people reach for a percentage calculator for both everyday and professional purposes, since percentage math comes up across so many different situations.
Shoppers calculate discount prices, sales tax totals, and price comparisons using percentage calculations while browsing or checking out.
Students calculate grade percentages, statistical figures, and math homework involving percentages, ratios, and proportions.
Professionals use percentage calculations for markups, margins, interest rates, growth rates, and budget allocations.
Diners calculate tip amounts and split bills that include a percentage-based service charge or tax.
Many people use percentage calculations simply to compare two numbers or understand how much one value has changed relative to another.
This calculator's three modes cover the vast majority of everyday percentage questions, each answering a slightly different type of question.
This mode answers "what is X% of Y?" — for example, "what is 20% of 150?" It's calculated by dividing the percentage by 100 and multiplying by the number, giving you a portion of the original value.
This mode answers "what is Y increased by X%?" — for example, calculating a price after a percentage markup, or a value after percentage growth. It takes the original number and adds the calculated percentage amount on top of it.
This mode answers "what is Y decreased by X%?" — for example, calculating a sale price after a percentage discount. It takes the original number and subtracts the calculated percentage amount from it.
It's worth distinguishing these direct calculations from "percentage change," which measures how much a value has changed relative to its original amount — calculated as (new value − original value) ÷ original value × 100. This calculator's "+%" and "-%" modes go the other direction: starting from a known percentage and a base number to find the resulting value, rather than starting from two values to find the percentage difference between them.