Free percentage tool

Reverse Percentage Calculator

Work backward from a final number to find the original value before an increase, decrease, discount, tax, VAT, or percentage relationship.

Reverse percentage
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Original value

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Formula

Reverse percentages use the final value and percentage relationship to recover the starting value.

original after increase = final ÷ (1 + percent/100) original after decrease = final ÷ (1 - percent/100) whole when part is p% = part ÷ (p/100)

Examples

  • If 120 is after a 20% increase, original = 120 ÷ 1.20 = 100.
  • If 80 is after a 20% discount, original = 80 ÷ 0.80 = 100.
  • If 30 is 20% of a number, original = 30 ÷ 0.20 = 150.

Frequently asked questions

Short, practical answers for this calculation.

When should I use reverse percentage?

Use it when you know the final value and the percentage relationship but need the original value.

How do I reverse a discount?

Divide the sale price by 1 minus the discount rate. For 20% off, divide by 0.80.

How do I remove VAT or tax?

Divide the gross price by 1 plus the VAT or tax rate.

Why is reversing a percentage not the same as subtracting it?

Because the percentage is based on the original value, not the final value.