Percentage Calculator - Calculate Increase, Decrease & Difference

Calculate percentages easily. Free tool for finding percentage change, increases, discounts, and weighted averages. Instant accurate results for finance.

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Perform various percentage calculations with precision using our comprehensive Percentage Calculator. Whether you need to calculate tips, discounts, growth rates, markup percentages, or weighted averages, this tool handles it all. From simple "X% of Y" calculations to complex compound growth, percentage error, and distribution analysis, we support 15 distinct modes. All calculations use high-precision decimal arithmetic for accurate results, making it perfect for students, professionals, and everyday use.

How to Use Percentage Calculator

Basic Percentage Calculations (X% of Y)

For simple calculations like "what is 15% of 200", select the "X% of Y" mode. Enter the percentage (e.g., 15) and the number (e.g., 200), then click Calculate. Ideally suited for calculating tips, sales tax, or simple portions.

Find the Percentage (X is what % of Y)

Determine what percentage one number is of another. Useful for calculating test scores (e.g., 45 out of 50) or determining completion rates. Enter the part and the whole to see the percentage value immediately.

Percentage Change (Increase/Decrease)

Calculate the percentage difference between two values. ideal for tracking price changes, weight loss, or analyzing trends. Enter the original value and the new value to see if it's an increase or decrease and by how much.

Add or Subtract Percentage

Quickly apply a percentage to a number. Use "Add" for calculating total price with tax or "Subtract" for calculating discounted prices. Enter the base value and the percentage to get the final result instantly.

Reverse Percentage Calculator

Find the original value before a percentage change occurred. If you know the final price after tax and want the pre-tax price, this is the mode. Enter the final value and the percentage applied to work backwards.

Successive Percentage Changes

Apply multiple percentage changes one after another. For example, a stock rises 10%, then falls 5%. Enter the starting value and a list of changes to see the cumulative effect and final value.

Percentage Points vs. Percent Change

Distinguish between absolute percentage point differences and relative percentage changes. Essential for statistics and finance where "rates" change (e.g., interest rate moving from 4% to 5%).

Part-Percent-Whole Solver

A universal solver for the basic percentage formula: Part = Percentage × Whole. If you know any two variables, this mode calculates the third missing one automatically.

Percentage Error Calculator

Compare an experimental or measured value to a theoretical or accepted true value. Widely used in science (physics, chemistry) and engineering labs to determine accuracy.

Distribution Analysis

Analyze how a total is distributed among different categories. Enter a list of values (e.g., expenses by category) to see what percentage each contributes to the total sum.

Compound Growth Calculator

Calculate the future value of an investment or population that grows at a constant percentage rate per period. Perfect for clear visualization of compound interest effects over time.

Markup and Markdown Calculator

Essential for retail and business pricing. Calculate "Markup" based on cost to set selling prices, or "Markdown" to plan sales and discounts. Understand the difference between markup on cost and profit margin.

Percent Needed for Target

Determine the percentage increase or decrease required to go from a current value to a desired target value. Great for goal setting in sales, fitness, or savings.

Weighted Average Calculator

Compute averages where some values count more than others. Indispensable for calculating course grades (where exams weigh more than homework) or portfolio returns.

Percentage Split

Divide a total amount into specific percentage portions. Useful for splitting bills, allocating budgets, or distributing resources according to defined ratios.

Calculator Features

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Comprehensive Modes

Access 15 specialized modes for every type of percentage calculation imaginable.

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Reverse Calculations

Easily find original values from final totals, perfect for reverse tax calculations.

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Compound Growth

Visualize how investments or populations grow over time with compounding.

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Distribution & Splits

Analyze data distributions and split totals accurately by percentage ratios.

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Retail Pricing Tools

Business-ready Markup and Markdown modes for accurate profit margin analysis.

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Weighted Averages

Calculate complex averages for grades or finance with reliable precision.

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Part-Percent-Whole

Flexible solver that finds the missing variable in any percentage equation.

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Error Analysis

Scientific percentage error calculations for laboratory and engineering use.

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Step-by-Step Logic

View the detailed breakdown of every calculation to understand the "how".

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Precision Control

Adjust decimal places to suit your needs, from round numbers to high precision.

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Mobile Friendly

Fully responsive design that works perfectly on phones, tablets, and desktops.

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Instant Results

Get answers immediately as you type or adjust values, with zero latency.

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Input Validation

Smart validation ensures your inputs make sense, preventing simple errors.

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Copy & Share

One-click copy function to easily paste results into documents or messages.

Complete Function List

  • Calculate X% of Y (Standard Percentage):
  • Determine what % X is of Y:
  • Calculate Percentage Change (Increase/Decrease):
  • Add Percentage to a Number (Tax/Tips):
  • Subtract Percentage from a Number (Discounts):
  • Reverse Percentage Calculator (Find Original Value):
  • Successive Percentage Changes (Multi-step):
  • Compound Growth Calculator (Investment/Population):
  • Markup Calculator (Cost to Price):
  • Markdown Calculator (Price Reductions):
  • Target Percentage Finder:
  • Weighted Average Calculator:
  • Percentage Splitter:
  • Distribution Analysis:
  • Part-Percent-Whole Universal Solver:
  • Percentage Point vs Relative Change:
  • Percentage Error for Science/Engineering:
  • Step-by-step calculation explanations:
  • Adjustable decimal precision:
  • High-precision decimal arithmetic:

Common Calculations & Examples

Example 1: Calculate a Tip

Problem: What is a 20% tip on a $54.50 dinner bill?

Steps:

  1. Select "X% of Y" mode
  2. Enter X (Percentage): 20
  3. Enter Y (Number): 54.50
  4. Click Calculate
Result: $10.90

Explanation: Multiply 0.20 (20%) by $54.50 to get $10.90. The total bill would be $54.50 + $10.90 = $65.40.

Example 2: Find Sales Tax

Problem: A laptop is $999. Sales tax is 8.5%. What is the total?

Steps:

  1. Select "Add/Subtract Percentage" mode
  2. Enter Base: 999
  3. Enter Percent: 8.5
  4. Select Operation: Add
  5. Click Calculate
Result: $1,083.92

Explanation: 8.5% of $999 is $84.915. Adding this to the base price of $999 gives a total of $1,083.915, rounded to $1,083.92.

Example 3: Calculate Discount

Problem: A $120 jacket is 25% off. What is the sale price?

Steps:

  1. Select "Add/Subtract Percentage" mode
  2. Enter Base: 120
  3. Enter Percent: 25
  4. Select Operation: Subtract
  5. Click Calculate
Result: $90.00

Explanation: Subtract 25% ($30) from the original $120. The final price is $90. You pay 75% of the original price.

Example 4: Reverse Tax Calculation

Problem: You paid $108 total including 8% tax. What was the price before tax?

Steps:

  1. Select "Reverse Percentage" mode
  2. Enter Final: 108
  3. Enter Percent: 8
  4. Select Direction: Increase
  5. Click Calculate
Result: $100.00

Explanation: Divide $108 by 1.08 to reverse the 8% increase. $100 * 1.08 = $108.

Example 5: Stock Market Fluctuations

Problem: A stock starts at $100, goes up 10%, then down 10%. What is it worth?

Steps:

  1. Select "Successive Changes" mode
  2. Enter Base: 100
  3. Add Change: +10
  4. Add Change: -10
  5. Click Calculate
Result: $99.00

Explanation: First, $100 + 10% = $110. Then, $110 - 10% = $99. Note: It does not return to $100 because the decrease applies to the higher value.

Example 6: Calculate Grades (Weighted Average)

Problem: Test 1 (80%) is worth 20%, Final (90%) is worth 80%. What is the grade?

Steps:

  1. Select "Weighted Average" mode
  2. Row 1: 80% with weight 20
  3. Row 2: 90% with weight 80
  4. Click Calculate
Result: 88%

Explanation: (80*20 + 90*80) / (20+80) = (1600 + 7200) / 100 = 8800 / 100 = 88%.

Example 7: Investment Compound Growth

Problem: Invest $5,000 at 7% annual return for 10 years.

Steps:

  1. Select "Compound Growth" mode
  2. Enter Initial: 5000
  3. Enter Percent: 7
  4. Enter Periods: 10
  5. Click Calculate
Result: $9,835.76

Explanation: Using the formula 5000 * (1.07)^10, the investment nearly doubles over 10 years due to compounding.

Example 8: Markup for Retail

Problem: You buy an item for $50 and want a 50% markup. What is the selling price?

Steps:

  1. Select "Markup/Markdown" mode
  2. Enter Cost: 50
  3. Enter Selling Price: (Leave blank to solve) -> NOTE: Tool typically calculates markup %.
  4. Here: Enter Cost 50, Selling Price 75 -> Calculates 50% Markup.
Result: 50% Markup

Explanation: Markup is ($75 - $50) / $50 = 0.50 or 50%. A 50% markup results in a 33.3% profit margin.

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