Discount Calculator
Price and discount in, final price and savings out. Or run it backwards to recover the original price.
Final price
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You save
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Effective discount
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Worked example
30% off 120 gives 84. Stacking a further 10% takes it to 75.60, which is 37% off in total — not 40%. Discounts multiply, they do not add.
Stacked discounts are the classic arithmetic trap. "30% off, then an extra 10%" is not 40% off; it is 37%. The second discount applies to the already-reduced price, so the bases differ.
Recovering the original price
If something costs 84 after 30% off, the original is 84 ÷ 0.7 = 120, not 84 × 1.3 = 109.20. Multiplying by 1.3 adds 30% of the sale price, which is a smaller number than 30% of the original.