Percentage Calculator

Worked examples

A few common percentages, calculated with the same formula the calculator above uses (percent divided by 100, then multiplied by the amount):

• 10% of 250 = 25
• 20% of 250 = 50
• 25% of 200 = 50
• 50% of 90 = 45
• 15% of 80 = 12
• 7.5% of 640 = 48

Common percentage values

A quick-reference table for the percentages that come up most in everyday calculations: discounts, tips, grades, and splitting bills. Find the percentage column, then read down to the amount you're working with, or use the calculator above for anything not listed here.

How each mode works

The calculator above has three tabs, one per question. Switch between them with a click, or with the arrow keys once a tab is focused.

• "What is X% of Y?": enter a percentage and an amount, get the result. Example: what is 20% of 200? Answer: 40. This is the most common version of the question, and it's the tab that opens first.
• "X is what % of Y?": enter two amounts, get the percentage the first represents of the second. Example: 40 is what % of 200? Answer: 20%. Useful for turning a score, a count, or a fraction into a percentage.
• "Increase / decrease %": enter a starting number and a percentage, choose Increase or Decrease, get the new value. Example: increase 100 by 15% and the result is 115; decrease 100 by 15% and the result is 85. Useful for price changes, raises, and discounts.

Real-world examples for each mode

Seeing the three modes applied to everyday situations makes it easier to recognize which one to reach for.

Shopping discount (mode 1). A jacket costs $80 and is on sale for 30% off. Enter 30 as the percentage and 80 as the amount in the first tab: the result is 24, meaning you save $24 and pay $56.

Test score (mode 2). You answered 42 questions correctly out of 50 on a test. Enter 42 and 50 in the second tab: the result is 84%, your score as a percentage.

Restaurant tip (mode 1 again). Your bill comes to $45 and you want to leave an 18% tip. Enter 18 and 45 in the first tab: the result is 8.10, so you'd leave about $8 on top of the bill.

Salary raise (mode 3). Your salary is $52,000 and you're getting a 4% raise. Enter 52000 as the starting number and 4 as the percentage, choose Increase: the new salary is $54,080.

Price after markdown (mode 3 again). A $1,200 laptop is marked down by 12%. Enter 1200 and 12, choose Decrease: the new price is $1,056.

Percentage vs. percentage points

One mix-up worth avoiding: a change measured in percentage points is not the same as a percentage change. If an interest rate moves from 5% to 8%, that's a change of 3 percentage points, but it's a 60% increase in the rate itself (3 divided by 5, times 100). News articles and financial reports sometimes blur this distinction, so when a number seems surprisingly large or small, check whether it's describing a percentage-point difference or a percentage change of the original value. The third tab of the calculator above handles the second kind, applying a percentage change to a starting number.

When you'd use this calculator

Percentage calculations come up constantly outside of math class: figuring out a discount at checkout, calculating a tip, comparing test scores, tracking a pay raise, or working out how much a price changed year over year. This calculator covers the three most common versions of that question so you don't have to redo the arithmetic by hand every time. See the step-by-step guide if you'd rather learn the manual method, or the formula reference page if you just want every formula laid out in one place, including percentage change and percentage difference between two values. No numbers you enter here are stored or sent anywhere, as explained in the privacy policy.

Percentages in everyday contexts

The same three formulas behind this calculator show up under different names depending on the field. Recognizing them makes it easier to know which tab to reach for.

Grades and test scores. Converting a raw score into a percentage ("X is what % of Y") is the second tab: 34 correct out of 40 questions is (34 ÷ 40) × 100 = 85%. Working out how many points a certain percentage represents on a test is the first tab: 90% of a 40-point test is 36 points.

Sales tax and fees. Adding a fixed-rate tax or service fee onto a price is the third tab's Increase mode: a $60 purchase with 8% sales tax becomes $64.80.

Sports and win rates. A team that won 24 out of 30 games has a win percentage found with the second tab: (24 ÷ 30) × 100 = 80%.

Recipes and scaling. Scaling a recipe up by a percentage, say increasing every ingredient by 50% to serve more people, uses the third tab's Increase mode on each ingredient amount.

Surveys and statistics. Reporting that 168 out of 240 survey respondents agreed with a statement is a second-tab calculation: (168 ÷ 240) × 100 = 70%.

Frequently confused percentage questions

A handful of phrasings look similar but call for a different tab or a different order of numbers. Getting this right up front avoids re-doing the calculation.

• "What is 20% of 80?" (first tab, percent then amount) is not the same question as "20 is what % of 80?" (second tab, part then total). The first answer is 16; the second is 25%.
• "Increase 80 by 20%" (third tab, result 96) is not the same as "80 is 20% more than what number?" (a reverse calculation this calculator's three tabs don't directly solve; it requires dividing 80 by 1.20, giving roughly 66.67).
• "What percent did the value increase" when you're given a before-and-after pair (for example $80 to $96) is a percentage change question, covered on the percentage formula page, rather than the third tab's increase/decrease mode, which goes in the opposite direction: from a starting number and a known percentage to a new value.
• A percentage "of" a negative number, or a negative percentage itself, is mathematically valid but easy to mistype; double-check the sign of both inputs if a result looks unexpectedly negative or positive.

Tips for getting an accurate result

A few small habits help avoid the most common percentage mistakes, whether you're using this calculator or working something out by hand.

• Double-check which number is the "whole" and which is the "part" before you calculate. Swapping them in mode 2 gives a very different, and usually wrong, answer.
• Remember that a percentage can be greater than 100%. If you scored 120 points out of a possible 100 with extra credit, that's 120%, and the calculator will show it correctly rather than capping the result.
• When comparing two successive percentage changes (a 10% increase followed by a 10% decrease), don't assume they cancel out. Applying them one after another in the third tab will show they don't return to the original number.
• For money amounts, enter the raw number without a currency symbol or comma (450 rather than $450 or 1,000 rather than 1000, which the calculator also accepts without commas).
• If a result looks off by a factor of 100, check whether you multiplied by the raw percentage number instead of dividing it by 100 first; this single missed step is the most common source of a wrong answer when working by hand instead of using the calculator above.

Why use a calculator instead of a phone's built-in calculator

A standard calculator app can compute a percentage, but only if you already remember the right sequence of operations for the specific question you're asking, and that sequence changes depending on which of the three modes above you need. This tool removes that step: pick the tab that matches your question in plain English, type in the two numbers you already know, and the labeled result appears immediately, with a short sentence explaining what it means rather than a bare number. That's also why each tab keeps its own separate fields, so switching questions doesn't require re-entering a value you already typed for a different mode.