How to find a number before a percentage mark-up has been added
When businesses price their items for sale, the difference between the wholesale cost of the item and the retail price is called the markup. Businesses usually report the markup as a percentage.
If you know the sales price and the markup percentage, you can calculate the original price before the markup has been added.
Convert the percentage markup to a decimal by dividing by 100. For example, if you were using a 20 per cent markup, you would divide 20 by 100 to get 0.2.
Add 1 to the markup expressed as a decimal. In this example, you would add 1 to 0.2 to end with 1.2.
Divide the price after markup has been added by the result from step 2 to find the price before the markup. For example, if the final price of the item is £156, you would divide £156 by 1.2 to find the price before the markup to be £130.