Please provide any two values below and click "Calculate" to get the third value.
Please provide any two values below and click "Calculate" to get the third value.
A percentage calculator is one of the most useful everyday math tools you can have. Percentages appear everywhere - in store discounts, restaurant tips, sales tax, exam scores, interest rates, statistics, and nutrition labels. Yet many people freeze when they need to work one out by hand. This page brings together four complete percentage calculators so you can solve almost any percentage problem instantly: a flexible Percentage Calculator that solves for any missing value, a Common Phrases tool that answers questions the way you naturally ask them, a Percentage Difference Calculator, and a Percentage Change Calculator for increases and decreases. Below the calculators you will find clear explanations, formulas, and worked examples for each one.
The word percent comes from the Latin per centum, meaning "by the hundred." A percentage is simply a way of expressing a number as a fraction of 100. When you say 25 percent, you mean 25 out of every 100, which is the same as the fraction 25/100 and the decimal 0.25. This is why percentages are so convenient: they put every proportion on the same easy-to-compare scale of 100, no matter how large or small the original quantities are.
The percent sign, %, is shorthand for "divided by 100." So 40% is 40 ÷ 100 = 0.4, and 150% is 150 ÷ 100 = 1.5. Converting between a percentage, a decimal, and a fraction is the foundation of every percentage calculation. To turn a percentage into a decimal, divide by 100 (move the decimal point two places to the left). To turn a decimal into a percentage, multiply by 100 (move the decimal point two places to the right). For example, 0.075 becomes 7.5%, and 3% becomes 0.03.
Almost every percentage question is built on a single relationship between three quantities: the percentage (the rate), the base (the whole, often introduced by the word "of"), and the part (the result). The core formula is:
Part = (Percentage ÷ 100) × Base
Because this is a single equation with three variables, if you know any two of them you can always find the third. That is exactly what the first calculator on this page does. The equation reads "P% of B = Part." Fill in any two boxes, leave the third blank, and the calculator rearranges the formula for you:
This flexibility is what makes a percentage calculator so powerful. Instead of memorizing three separate procedures, you work from one formula and let the tool solve for whatever is missing.
Finding a percentage of a number is the calculation people perform most often, usually for discounts, tips, taxes, and commissions. The method is always the same: convert the percentage to a decimal and multiply by the number.
Suppose a $250 jacket is on sale for 30% off. To find the discount, calculate 30% of 250: 0.30 × 250 = $75. The sale price is therefore $250 − $75 = $175. You could also reach the price directly by recognizing that paying after a 30% discount means paying 70% of the original: 0.70 × 250 = $175. Both routes give the same answer, and the Percentage Change Calculator further down this page automates exactly this kind of discount math.
Tips work the same way. On a $64 restaurant bill, an 18% tip is 0.18 × 64 = $11.52. Sales tax is identical in structure: an item priced at $45 in a region with a 7.25% tax rate carries 0.0725 × 45 = $3.26 in tax, for a total of $48.26.
Sometimes you already know the part and the whole, and you want to express their relationship as a percentage. This is the "X is what percent of Y" question answered by the second calculator in the Common Phrases section. The formula is:
Percentage = (Part ÷ Whole) × 100
For example, if you scored 42 out of 50 on a test, your percentage is (42 ÷ 50) × 100 = 84%. If 27 of the 45 people in a room are women, then women make up (27 ÷ 45) × 100 = 60% of the group. This calculation is the backbone of grading, survey results, market share figures, and any situation where you need to turn a raw count into a proportion.
The reverse question - "X is P% of what number?" - comes up when you know a part and the percentage it represents but need the original total. The third Common Phrases calculator handles this with the formula:
Whole = Part ÷ (Percentage ÷ 100)
Imagine you paid $18 in tax and you know the tax rate was 6%. The pre-tax amount is 18 ÷ 0.06 = $300. Or suppose a salesperson earned a $1,200 commission that represents 4% of their sales; their total sales were 1,200 ÷ 0.04 = $30,000. This "working backward" calculation is extremely handy for reverse-engineering original prices, totals, and quantities.
The Percentage Difference Calculator answers a different kind of question: how far apart are two values, expressed as a percentage, when neither one is obviously the "starting" value? Percentage difference is symmetric - it does not matter which value you call the first and which you call the second - because it compares the gap between them to their average. The formula is:
Percentage Difference = ( |V1 − V2| ÷ ((V1 + V2) ÷ 2) ) × 100
The vertical bars mean "absolute value," so the result is always positive. Suppose two stores sell the same appliance for $120 and $80. The difference between the prices is $40, and their average is $100, so the percentage difference is (40 ÷ 100) × 100 = 40%. Because it uses the average as the reference point, percentage difference is the right tool when the two numbers are simply two measurements of the same kind - two prices, two lab readings, two populations - rather than a clear "before and after" pair.
The Percentage Change Calculator measures how much a value has grown or shrunk relative to its original amount. Unlike percentage difference, percentage change is directional: it has a clear starting value and a clear ending value, and the original value is always the reference. The formulas are:
Percentage Increase: New = Original × (1 + Percentage ÷ 100)
Percentage Decrease: New = Original × (1 − Percentage ÷ 100)
If a stock worth $500 rises 10%, its new value is 500 × 1.10 = $550. If it instead falls 10%, its new value is 500 × 0.90 = $450. The calculator on this page lets you choose "Increase" or "Decrease" from the dropdown and solve for any missing value, so you can also work backward - for instance, finding what percentage increase turns $500 into $620, or what original value becomes $550 after a 10% rise.
To compute percentage change from a known before and after value, use:
Percentage Change = ( (New − Original) ÷ Original ) × 100
A positive result is an increase and a negative result is a decrease. If sales rose from 200 units to 260 units, the change is ((260 − 200) ÷ 200) × 100 = 30%. If a town's population fell from 50,000 to 47,500, the change is ((47,500 − 50,000) ÷ 50,000) × 100 = −5%, a 5% decrease.
These two ideas are often mixed up, but they answer different questions and usually give different numbers. Percentage change compares the difference to the original value and has a direction (up or down). Percentage difference compares the difference to the average of the two values and has no direction. Consider going from 40 to 60. The percentage change is (20 ÷ 40) × 100 = 50% increase, because 40 is the starting point. The percentage difference is (20 ÷ 50) × 100 = 40%, because 50 is the average of 40 and 60. Use percentage change when there is a clear before-and-after; use percentage difference when you are simply comparing two independent measurements.
Percentages are woven through finance and everyday decisions. Shoppers use them for discounts and sales tax. Diners use them for tips. Borrowers and savers deal with annual percentage rates on loans, mortgages, and savings accounts - our interest calculator and investment calculator build directly on percentage math. Students track grades as percentages, investors track returns, nutritionists track the percent of daily values on food labels, and analysts track growth rates and market share. Becoming comfortable with percentages pays off in countless small decisions every week.
You will not always have a calculator within reach, so a few mental shortcuts help. To find 10% of any number, just move the decimal one place to the left: 10% of 240 is 24. From there, 5% is half of 10% (12), 20% is double 10% (48), and 15% is 10% plus 5% (36) - handy for tipping. To find 1%, move the decimal two places left. Because percentages are reversible, "x% of y" always equals "y% of x," which can make a problem easier: 8% of 50 is the same as 50% of 8, which is simply 4. These tricks let you sanity-check the calculator's output and handle quick estimates on the spot.
Convert the percentage to a decimal by dividing by 100, then multiply by the number. For 25% of 80, compute 0.25 × 80 = 20. The first calculator on this page does this automatically - enter the percentage and the number and leave the result box blank.
Divide the part by the whole and multiply by 100. For example, 30 out of 120 is (30 ÷ 120) × 100 = 25%. Use the "X is what % of Y" calculator in the Common Phrases section above.
Percentage change measures growth or decline relative to a single original value and has a direction (increase or decrease). Percentage difference compares two values against their average and is always positive. Use change for before-and-after comparisons and difference for comparing two independent measurements.
For an increase, multiply the original value by (1 + rate/100); for a decrease, multiply by (1 − rate/100). A $200 item increased by 15% becomes 200 × 1.15 = $230. The Percentage Change Calculator above handles both directions and can also solve for the rate or the original value.
Because each percentage is applied to a different base. Increasing $100 by 20% gives $120; decreasing $120 by 20% removes $24, leaving $96. The decrease is calculated on the larger $120, so the two moves do not cancel out.
No. Every calculation runs entirely in your browser. Nothing you type is sent to a server, so your numbers stay completely private.
This Percentage Calculator is provided for educational and general informational purposes. While it uses standard mathematical formulas and is suitable for everyday calculations, always double-check critical figures - especially those involving money, taxes, or contracts - against an authoritative source or professional advice.