How to Use This Tool
Pick a Calculation Mode
Choose from six modes: percentage of a number, what percent one number is of another, reverse percentage, increase/decrease, percentage change, or percentage difference.
Enter Your Numbers
Type the values into the input fields. Results calculate instantly as you type — no button needed. Each mode has clearly labeled inputs.
Read the Result and Formula
The answer appears in bold with a step-by-step formula below showing exactly how the calculation was done. Increase results are green, decrease results are red.
Copy Any Result
Click Copy under any result to copy the formula and answer to your clipboard. Paste it into a document, message, or spreadsheet.
Frequently Asked Questions
How do I calculate a percentage of a number?
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Multiply the number by the percentage and divide by 100. For example, 20% of 150 is (150 x 20) / 100 = 30. This calculator does this instantly — just enter the percentage and the number.
How do I find what percentage one number is of another?
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Divide the part by the whole and multiply by 100. For example, 30 is what percent of 200? (30 / 200) x 100 = 15%. Enter both numbers in the 'X is what % of Y' section to get the answer.
How do I calculate percentage increase between two numbers?
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Subtract the old value from the new value, divide by the old value, and multiply by 100. For example, from 200 to 250: ((250 - 200) / 200) x 100 = 25% increase. Use the Percentage Change section for this.
How do I calculate percentage decrease?
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Subtract the new value from the old value, divide by the old value, and multiply by 100. For example, from 200 to 150: ((200 - 150) / 200) x 100 = 25% decrease. The Percentage Change section handles both increases and decreases.
What is the difference between percentage change and percentage difference?
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Percentage change compares an old value to a new value with a direction (increase or decrease). Percentage difference compares two values without a direction — it measures how far apart they are relative to their average. Use change when order matters, difference when it does not.
How do I add a percentage to a number?
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Multiply the number by (1 + percentage/100). For example, 200 increased by 15% = 200 x 1.15 = 230. The Increase/Decrease section calculates this for you instantly.
How do I subtract a percentage from a number?
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Multiply the number by (1 - percentage/100). For example, 200 decreased by 15% = 200 x 0.85 = 170. Enter the number and percentage in the Increase/Decrease section and select Decrease.
How do I calculate a discount percentage?
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Use the 'X is what % of Y' section. Enter the discount amount as X and the original price as Y. For example, if an item is $80 and the discount is $20, then 20 is what % of 80 = 25% discount.
How do I reverse-calculate the original price from a percentage?
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Use the 'X is Y% of what' section. If you know the result and the percentage, enter them to find the original number. For example, 30 is 15% of what? Answer: 200.
Is this percentage calculator free to use?
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Yes. This calculator is completely free, runs entirely in your browser, and requires no registration. Your data is never sent to any server.
Free Percentage Calculator — Calculate Percentages, Increases, Decreases, and Differences Instantly
A percentage calculator is a tool that solves all common percentage problems in seconds. Whether you need to find what percentage one number is of another, calculate a percentage of a number, figure out percentage increase or decrease between two values, or determine the percentage difference, this tool covers every scenario. Percentages are used everywhere — shopping discounts, tax rates, exam scores, salary raises, investment returns, and statistical analysis.
This free online percentage calculator provides six calculation modes on one page, all with instant results and step-by-step formulas. Enter your numbers and see the answer immediately — no buttons to click, no pages to navigate. Each result includes the exact formula with your numbers so you can understand and verify the math. Color coding highlights increases in green and decreases in red for quick visual clarity. Whether you are calculating a tip, figuring out a discount, checking your exam percentage, or analyzing business growth, this tool gives you accurate results instantly with no sign-up required.
Features Explained
What is X% of Y?
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The most common percentage calculation. Enter a percentage and a number to find the result. Perfect for calculating tips, discounts, tax amounts, and commissions.
X is What % of Y?
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Find what percentage one number represents of another. Useful for calculating exam scores (45 out of 60 = 75%), completion rates, and proportions.
X is Y% of What?
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Reverse percentage calculation. If you know the result and the percentage, find the original number. Useful for finding the original price before a discount.
Increase or Decrease by %
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Add or subtract a percentage from a number. Toggle between increase (+) and decrease (-). Shows the final value after applying the percentage change. Green for increase, red for decrease.
Percentage Change (From / To)
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Calculate the percentage change between two values. Shows whether it is an increase or decrease and by how much. Commonly used for salary changes, price changes, and growth analysis.
Percentage Difference
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Calculate the percentage difference between two values without regard to direction. Uses the average of both values as the base. Useful for comparing two measurements or data points.
Step-by-Step Formula Display
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Every result includes the exact formula with your numbers plugged in. This shows how the answer was calculated, helping you learn the method and verify the result.
Color-Coded Results
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Increases and positive changes appear in green. Decreases and negative changes appear in red. Neutral calculations use the primary theme color. Visual color coding makes results immediately clear.
Per-Result Copy Button
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Each calculation mode has its own Copy button. Click it to copy the formula and result for that specific calculation. No need to select text manually.
Instant Real-Time Calculation
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All six modes calculate results as you type. No submit button needed. Change any input and the result updates immediately.
Who Is This Tool For?
Students Doing Math Homework
Solve percentage problems instantly and see the step-by-step formula to learn the method for exams.
Shoppers Calculating Discounts
Find the final price after a percentage discount. Calculate how much you save on sale items before buying.
Restaurant Diners Calculating Tips
Quickly figure out 15%, 18%, or 20% of your bill. Never wonder how much to tip again.
Teachers Grading Exams
Convert raw scores to percentages. Find out what percentage 37 out of 50 is without mental math.
Business Owners Analyzing Growth
Calculate percentage change in revenue, customers, or expenses from one period to another.
Sales Professionals Calculating Commission
Find your commission amount based on a percentage of total sales. Quick and accurate every time.
Investors Tracking Returns
Calculate percentage gain or loss on investments. Compare returns across different assets and time periods.
Accountants Working with Tax Rates
Calculate tax amounts, deductions, and effective rates. Find percentage of income paid in taxes.
Real Estate Agents
Calculate agent commission percentages, price increases, and property value changes for clients.
Fitness Enthusiasts Tracking Progress
Calculate percentage of body weight lost, strength gained, or distance improved over your training period.
Project Managers Tracking Completion
Calculate what percentage of a project is complete based on tasks finished versus total tasks.
Researchers Analyzing Data
Calculate percentage difference between experimental and control groups. Essential for statistical analysis.
Parents Helping Kids with Math
Solve percentage homework problems together and show children the step-by-step formula for each type.
Freelancers Pricing Services
Calculate markup percentages on costs, discount rates for bulk work, and percentage-based rate increases.
HR Professionals Calculating Raises
Determine salary after a percentage raise. Compare different raise percentages across employee levels.
Marketing Teams Analyzing Conversion Rates
Calculate conversion percentages, click-through rates, and campaign performance metrics.
Loan Borrowers
Understand what percentage of your payment goes to interest. Calculate how rate changes affect your total cost.
Cooks Scaling Recipes
Increase or decrease ingredient quantities by a percentage when scaling recipes up or down.
Athletes Monitoring Performance
Calculate improvement percentages in speed, distance, or weight lifted between training sessions.
Journalists Reporting Statistics
Verify percentage claims in reports. Calculate percentage changes in public data for accurate reporting.
Pharmacists Calculating Concentrations
Determine percentage concentrations in solutions and compounds for prescription accuracy.
Event Planners Managing Budgets
Calculate what percentage of total budget each expense category represents. Track spending limits.
E-commerce Sellers Setting Prices
Calculate markup percentages, discount amounts, and profit margins for products listed online.
Anyone Who Needs Quick Percentage Math
Whether it is splitting a bill, understanding a statistic, or calculating a grade — this tool gives you the answer in seconds.
Tips for Using This Tool
Use the right mode for your question
Each mode solves a different type of percentage problem. Read the card titles to find the one that matches your question — 'of', 'is what %', 'of what', 'change', or 'difference'.
Check the formula to learn the method
Every result shows the step-by-step formula with your numbers. Study it to understand how percentages work so you can do it mentally next time.
Percentage change needs direction
Use Percentage Change when the order matters (old to new). Use Percentage Difference when comparing two values without a before/after relationship.
Use increase/decrease for applied percentages
To add tax, markup, or a raise — use Increase. To apply a discount, markdown, or reduction — use Decrease. The toggle switches between + and -.
Copy individual results
Each calculator card has its own Copy button. You can copy results from different modes independently without affecting others.
Use decimals for precision
All inputs accept decimal numbers. Enter 7.5 instead of rounding to 8 for more accurate results, especially for tax and interest calculations.
Reverse-calculate with Mode 3
If you know the result and the percentage but not the original number, use 'X is Y% of what?' to find it. This is the reverse of the standard percentage calculation.
Green means increase, red means decrease
Color-coded results make it immediately clear whether a change is positive or negative. No need to check signs.
Use for quick mental math verification
If you calculated a percentage in your head, plug the numbers in here to verify. The formula display confirms the method too.
All six modes work independently
Each calculator card operates on its own. Changing numbers in one mode does not affect any other. Use multiple modes simultaneously.
Privacy & Security
This percentage calculator runs 100% in your browser. Your numbers are never sent to any server, stored in any database, or shared with any third party. All calculations happen locally on your device.
No cookies, no analytics, no registration required. Your data stays completely private. Close the tab and everything is gone.