Free · Sales calculators 💸

Successive Discounts & Optional Sales Tax

Apply one or two successive percentage discounts, optionally add sales tax to the discounted price, and compare total savings.

  • Formula & worked example
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Use the result with context

Results are estimates for planning and education. Confirm rates, taxes, fees, and legal requirements with the relevant institution or a qualified professional before making a financial decision.

Formula and method

Starting at 100, discounts of 20 percent and then 25 percent leave 60 before tax. Adding 10 percent tax makes the final price 66; savings against the same-tax original price are 44.

Final price = original × (1 − first discount) × (1 − second discount) × (1 + selected tax rate)

Worked example

Enter these known values and leave the other values blank.

Original price before tax
100 USD
First price reduction
20 %
Apply a second discount
Apply a second discount
Second reduction on the reduced price
25 %
Add sales tax after discounts
Add sales tax
Sales tax rate
10 %
Final price with selected tax
66 USD
Savings against the same-tax original price
44 USD
Combined discount before tax
40 %

Assumptions and limitations

  • The second discount is applied to the already reduced price. Switching it off resets its contribution to zero.
  • Tax, when enabled, is applied after both discounts. Savings compare final price against the original price with the same selected tax rate.
  • The starting price is positive, both discounts lie between zero and 100 percent, and tax is nonnegative. A 100 percent discount leaves zero final price.
  • The initial 6 percent tax value is only an editable example. This model does not determine local tax law, coupon treatment, exemptions, rounding per line item or fees.

Common questions

Do 20 percent off and then 25 percent off equal 45 percent off?

No. The retained price fractions multiply: 0.80 × 0.75 = 0.60, equivalent to 40 percent off.

Why do savings change when I add tax?

The comparison includes the same tax rate on the undiscounted baseline. Reducing the taxable price also reduces modeled tax.

References

Bookify allows a fully discounted zero final price and constrains both discounts and their combined discount to zero through 100 percent.

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