Discount, price increase and percent change calculator
Work out a discount or a price rise in one step: 20% off 250 is 200, and 15% on top of 200 is 230. Type an old and a new price to see the change: from 200 to 230 is up 15%.
Updated:
New price
200.00
Discount
50.00
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The formulas
- Price after a discount = price × (1 − discount)
- Price after an increase = price × (1 + increase)
- Percent change = (new price − old price) ÷ old price
- Price before a discount = discounted price ÷ (1 − discount)
Two discounts do not add up
100 with 20% off, then 10% off: 100 × 0.80 = 80 80 × 0.90 = 72 28% off in all, not 30%
In the same way, a 20% increase and then a 20% discount do not bring the old price back: 100 → 120 → 96.
Price rises and customers on credit
Goods taken on credit are owed at the price of the day they were taken; a later price rise does not change an old debt. To see what waiting costs you, try the inflation calculator.
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Questions
How do I find the original price before a discount?
Divide the discounted price by 1 − the discount. If 20% off made it 200, the original price was 200 ÷ 0.80 = 250.
How do I work out a percentage increase?
Divide the difference by the old price and multiply by 100. A price that went from 40 to 50 rose (50 − 40) ÷ 40 = 25%.