Discount Calculator: Double and Triple Discounts

How to calculate double and triple discounts

When a store applies multiple discounts one after another, each new discount is applied to the price remaining after the previous discount. The discount percentages are not simply added together.

For example, a 20% discount followed by a 10% discount gives a combined effective discount of 28%, not 30%. The second discount is calculated on the reduced price.

Enter the original price and up to three discount percentages. Leave unused discount fields at 0. The calculator applies the discounts in order and shows your final price, total savings, effective discount, and amount you pay.

Formula

Let:

Let:

• $P$​​​​​​​ = original price
• $(d_1,d_2,\text{ and }{d}_3)$​​​​​​​ = discount percentages

Convert each discount percentage into a decimal rate:

$r_i$ = $\frac{d_i}{100}$

Calculate the price after each discount:

$P_1$ = $P(1-r_1)$

$P_2$ = $P_1(1-r_2)$

$P_3$ = $P_2(1-r_3)$

The final price after all entered discounts is:

$P_{\text{final}}$ = $P\prod _{i=1}^3\left(1-\frac{d_i}{100}\right)$

If fewer than three discounts are used, set each unused discount rate to zero.

Total savings:

$S$ = $P-P_{\text{final}}$

Effective discount percentage:

$D_{\text{effective}}$ = $\frac{S}{P}\times 100$

Amount you pay:

$\text{You Pay}=P_{\text{final}}$

Example calculation

Suppose an item costs $100 and has three sequential discounts: 20%, 10%, and 5%.

After Discount 1:

$P_1=100\left(1-\frac{20}{100}\right)=80$

After Discount 2:

$P_2=80\left(1-\frac{10}{100}\right)=72$

After Discount 3:

$P_3=72\left(1-\frac{5}{100}\right)=68.40$

So the results are:

• Final Price: $68.40
• Total Savings: $31.60
• Effective Discount: 31.6%
• You Pay: $68.40

The discounts total 35 percentage points, but the effective discount is 31.6% because each discount is applied to the remaining price.

What the results mean

• Final Price: The item price after all entered discounts.
• Total Savings: The difference between the original price and the final price.
• Effective Discount: Your total savings expressed as a percentage of the original price.
• You Pay: The final amount before any taxes, shipping fees, or other charges not included in the calculator.

FAQs

Are multiple discounts added together?

No. Sequential discounts are applied one after another to the reduced price. For example, 20% off followed by 10% off is not the same as 30% off.

How do I calculate two discounts?

Enter the original price and the first two discount percentages. Set Discount 3 to 0 or leave it blank if the calculator accepts empty fields.

How do I calculate three discounts?

Enter the original price and each discount percentage in the order they are applied. The calculator applies Discount 1 first, then Discount 2, then Discount 3.

What does “effective discount” mean?

It is the total savings expressed as a percentage of the original price. If a $100 item costs $70 after all discounts, the effective discount is 30%.

Does the final price include sales tax?

No. Unless the calculator specifically includes a tax input, the result is before sales tax, shipping, and other additional charges.

Can I use a discount of 0%?

Yes. A 0% discount leaves the current price unchanged. Use 0% for any discount field you do not need.

Why is my effective discount less than the sum of the discount percentages?

Because each discount after the first is applied to an already reduced price. The percentages are not all calculated from the original price.