Original Price Calculator
Work backwards from a discounted price to find the original.
How to find the original price
Original = Sale price ÷ (1 − discount% ÷ 100)
Example: Item costs $85 after a 15% discount. → 85 ÷ (1 − 0.15) = 85 ÷ 0.85 = $100
The calculator above uses the "find original value" formula: if $85 is 85% of the original price (because 15% was removed), then $85 is 85% of what? Enter 85 as the value and 85 as the percentage to get $100.
Common mistake: Don't add the discount back by multiplying the sale price by the discount rate. $85 + 15% of $85 = $97.75, not $100. You must divide by the remaining percentage (0.85), not multiply.
Frequently asked questions
Divide the sale price by 0.80 (which is 1 − 0.20). If the sale price is $80: 80 ÷ 0.80 = $100 original price.
For 15% GST (New Zealand): divide the inclusive price by 1.15. For 10% GST (Australia): divide by 1.10.