How to find the original value before an increase?

Enter the final new value and the percentage that was added. The calculator reveals the starting number.

What is the formula for reverse percentage increase?

Use the formula: Original Value = New Value / (1 + Percentage / 100). For example, to find the price before a 20% tax that resulted in 120, calculate 120 / 1.20 = 100.

Original Before Increase Calculator

What was the Original value before an Increase % resulted in the New value?

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Cannot calculate when increase is -100% (division by zero)

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Calculate the original value before a percentage increase, given the new value and percentage increase.

Practical Uses

Budget (Pre-Increase):
What was the original wedding budget [Original] before a 25% [Increase] boost made it £6,250 [New]?
£5,000

Investment (Pre-Growth):
What was the original ISA investment [Original] before a 12% [Increase] growth made it worth £2,240 [New]?
£2,000
Price Before Hike:
What was the original TV subscription [Original] before a 5% [Increase] hike made it £126 [New]?
£120
Rent Before Rise:
What was the original rent [Original] in Leeds before a 7% [Increase] rise made it £1,070 [New]?
£1,000
Pre-Growth Population:
What was the original population of Swindon [Original] before a 3% [Increase] growth brought it to 103,000 [New] people?
100,000
Salary Before Rise:
What was the original start-up salary [Original] before an 8% [Increase] pay rise made it £43,200 [New]?
£40,000

How to Use

Enter the new value (after the increase) in the first box.
Enter the increase percentage in the second box.
The original value (before increase) appears instantly.
Check "Round" if you want to keep the result to two decimal places.
Save it to your list with Enter or the "Save calculation" button.

How It Works

The Original Before Increase calculator uses this formula:

\text{Original} = \frac{\text{New Value}}{1 + \frac{\text{Increase}\%}{100}}

Example: What was the original if 125 is after a 25% increase?

\frac{125}{1 + \frac{25}{100}} = 100

The original value was 100.

What Is an Original Value Before Increase?

Definition

This calculation backs out a percentage that was added—VAT, service fees, surcharges, or markup—to reveal the starting amount. It is the mirror image of applying a markup: instead of growing the number, you peel away the added layer to see the base price. Use it when you want to know the shelf price before tax, the wholesale cost hidden inside a retail tag, or the pre-bonus salary behind total compensation. Because many receipts show only the final amount, being able to reverse the increase gives you transparency and lets you compare offers fairly across regions, vendors, or plans that bundle fees differently. It is also essential for contract review: if a vendor quotes '£108 with 8% tax included,' reversing the increase tells you the taxable base and whether the fee was applied correctly.

Common Applications

Reverse VAT Calculation: Finding the shelf price of an item by removing VAT from the total receipt amount.
Margin Analysis: Determining the wholesale cost of a product by removing the profit margin from the current retail price.
Salary Negotiations: Calculating what your base salary is versus your total compensation package including bonuses.
Inflation Adjustment: Estimating what a product might have cost a year ago based on today's inflated prices.
Utility bills: Stripping fees and surcharges to see the actual energy charge.
Loan fees: Removing arrangement or service fees to see the true principal before add-ons.

Mathematical Context

Original = Final ÷ (1 + Percent/100)

Divide instead of subtracting. If a £100 item has 20% VAT, you pay £120; reversing that is £120 ÷ 1.20 = £100. Subtracting a percent of the final would miss the mark because the percent belongs to the unknown base. With stacked increases, treat them as one combined factor (for example, 12% markup then 5% fee acts like 1.176) and divide once to uncover the starting value. When a receipt mixes several fees, this single division keeps the maths human-friendly even if the percentages are messy.

Need more percentage tools?

Basic Percentage Calculator
For discounts or taxes.
Part-to-Whole Percentage
Find what % one number is of another.
Original Value Calculator
Reverse a percentage to the original amount.
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 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.
Your saved calculations are 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

Instant results that appear as you type—no delays.
Round toggle to keep results neat (2 decimal places).
Copy results to clipboard with a single click.
Saved calculations that persist between sessions.
Clear visual formulas to understand the maths.
Mobile-friendly interface that works on all devices.
Dark mode support for comfortable viewing.
Keyboard shortcuts for faster calculations.