Reverse Percentage Calculator

Known percentage, %

Which equals

Result

The whole (100%)2,400
Formula360 × 100 ÷ 15
The rest2,040
The rest, %85%

Amount × 100 ÷ percent

Given a percentage and what it amounts to, recovers the whole, and shows how much sits in the remaining share.

It reads backwards but comes up constantly: the sale price is known and the original is not; a report gives a share and its value but never the total; tax was withheld and the gross has to be recovered.

The mechanics simply invert. If 15 percent equals 360, then one percent is 24 and the whole is 2,400.

What this calculator shows

The whole number and the formula that recovered it
What the remaining share is worth, in units and as a percentage
A figure you can verify by running it forward on the sibling page

What to keep in mind

The percentage cannot be zero — nothing can be recovered from a zero share.
To undo a discount, enter the share that survived: after 20 percent off you know 80 percent of the price, not 20.

FAQs

How do I recover the pre-discount price?

Enter the share left after the discount. At 25 percent off, the 75 percent you paid divided by 0.75 gives the original.

How do I get gross pay from net pay?

At a flat 13 percent, net is 87 percent of gross — enter 87 and the amount. Above the progressive threshold the net salary calculator is more accurate.

How do I strip VAT out of a gross figure?

The gross is 120 percent of the net at a 20 percent rate. Enter 120 and the total. The VAT calculator does the same with a breakdown.

Why can't I just add the same percentage back?

The base has changed. Take 20 percent off 1,000 and you get 800; add 20 percent to 800 and you get 960. The inverse of a percentage cut is division, not addition.

Worked example

Price before the discount

Input: 80% equals 800

Output: The whole is 1,000

Note: Entering 80 rather than 20 is the crux. A 20 percent discount means the 800 you paid is the remaining 80 percent.

Useful links

All tools in Math & Statistics

Reverse Percentage Calculator

Result

Related tools

Percent of a Number Calculator

Subtract a Percentage Calculator

VAT Calculator: Add VAT or Extract VAT

Useful links