Reverse Percentage Calculator - Calculate Original Value from Percentage
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.
Practical Uses
- Pre-Discount Price:
25% [X] of what original price [Y] is a $50 [Z] discount on a smartwatch?
$200 - Pre-Tax Amount:
8% [X] of what pre-tax amount [Y] is $16 [Z] sales tax?
$200 - Original Value:
15% [X] of what dinner bill [Y] is a 30 [Z] tip?
200 - Pre-Raise Salary:
10% [X] of what original base salary [Y] is a $5,000 [Z] raise?
$50,000 - Investment Principal:
12% [X] of what original seed capital [Y] is a $2,400 [Z] return?
$20,000 - Total Budget:
30% [X] of what total Christmas budget [Y] is $600 [Z]?
$2,000
How to Use
- Type the percentage in the first box.
- Enter the resulting number in the second box.
- The calculator instantly reveals the original value (the starting number before the percentage was applied).
- Check "Round" if you want to keep the decimals tidy.
- Hit "Add to Memos" or Enter to save it for later.
How It Works
The Original Value calculator uses this formula:
Example: If 15% equals 30, the original value is:
So the original value is 200.
Need more percentage tools?
- Basic Percentage Calculator
For discounts or taxes. - Part-to-Whole Percentage
Find what % one number is of another. - Percentage Change Calculator
Work out increases or decreases. - Increased Value Calculator
Calculate value after percentage increase. - Decreased Value Calculator
Calculate value after percentage decrease. - Original Before Increase Calculator
Find original amount before percentage increase. - Original Before Decrease Calculator
Find original amount before percentage decrease. - Specialized Calculators (63+)
Practical everyday calculations for real-life scenarios.
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.
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Your calculation memos 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 memos 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
- Verify Inputs: A small typo can make a big difference.
- Use Decimals: For precision, always use decimal points (e.g., 10.5).
- Instant Updates: Results appear immediately—no waiting.
- Rounding: Check "Round" to tidy up your results to 2 decimal places.