Finance 5 min read

Shopping Math: How to Calculate Double Discounts and Sale Prices

Avoid register surprises. Learn how to calculate shopping discounts and sales tax to find your exact cash savings.

Imaginex AI Finance Team
May 28, 2026

Retail Math Demystified

During retail sales events, store discounts are often listed as percentages off (e.g. '30% off'). Things get more complex when stores offer "double discounts," such as an extra 15% off already marked-down items.

Find your bargains instantly: [Discount & Sales Price Calculator](/tools/discount-calculator).

How to Calculate a Double Discount

A common mistake is adding the two percentages together (e.g., 20% off + 10% off is NOT 30% off). Double discounts must be applied sequentially:

  • Apply the primary discount to the original retail price to find the sale price.
  • Apply the secondary discount to that new sale price to find the final price.
  • This results in a total discount of 28% off the original price.

    Adjust price and discount sliders on the fly using our responsive [Discount & Sales Price Calculator](/tools/discount-calculator).

    Tags
    discount calculatorshopping tipssale pricesave moneytax

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