Reverse Percentage Calculator - Calculate Original Value from Percentage

Original Value
CALCULATOR

What is the original value if X% of it equals Z?

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    Help

    The Original Value calculator (also known as reverse percentage calculator) helps you find the original value when you know a percentage and its result. This is useful for working backward from a known percentage to find the original amount.

    How to Use

    1. Enter the percentage (X) in the first input field.
    2. Enter the result value (Z) in the second input field.
    3. Optionally, check the "Round" box to round the result to two decimal places.
    4. The calculator will instantly show the original value (Answer).
    5. Click "Add to History" or press Enter to save your calculation.

    How It Works

    The Original Value calculator uses this formula:

    Original Value=ResultPercentage/100\text{Original Value} = \frac{\text{Result}}{\text{Percentage} / 100}

    For example, if 25% of some value is 50, the original value would be:

    5025/100=500.25=200\frac{50}{25 / 100} = \frac{50}{0.25} = 200

    So the original value is 200.

    When to Use

    • Finding the original price before a discount was applied
    • Calculating the total amount before tax when you know the tax percentage and tax amount
    • Determining the original value when you know what percentage of it equals a specific amount
    • Figuring out the original salary when you know the percentage raise and new salary
    • Finding the original investment amount when you know the percentage return and final value

    Need more percentage tools?

    Requirements and Important Information

    • No installation required – works directly in your browser.
    • Compatible with all modern browsers (Chrome, Firefox, Safari, Edge).
    • Calculations are performed locally – no data is sent to any server.
    • Your calculation history is stored only on your device.
      Each calculator stores up to 20 most recent calculations, automatically removing the oldest entries when this limit is reached.
    • Works offline after the initial page load.
    • Supports both desktop and mobile devices.
    • No account or login required.

    Helpful Calculator Features

    • Real-time calculations that update as you type.
    • Copy results to clipboard with a single click.
    • Calculation history that persists between sessions.
    • Option to round results for cleaner numbers.
    • Clear visual formulas to understand the math.
    • Mobile-friendly interface that works on all devices.
    • Dark mode support for comfortable viewing.
    • Keyboard shortcuts for faster calculations.

    Tips for Accurate Calculations

    • Double-check input numbers for accuracy.
    • Use decimal points for precision.
    • Calculations update instantly as you type.
    • When the Round checkbox is checked, numbers are rounded to 2 decimal places.