Discount calculator

How to calculate a discount

1. Enter the original price.
2. Enter one or more discount percentages depending on the mode.
3. Add a sales-tax rate for a tax-inclusive total if you need one.
4. Read the sale price, savings, and effective percent off in the result panel.

Common uses

• Comparing seasonal promotions or two competing offers
• Checking the impact of stacking a coupon on top of an existing sale
• Computing wholesale or volume discounts for a quotation
• Pairing with the percentage calculator or tip calculator for everyday math

Technical specification

• Algorithm or formula: Single discount: sale = price × (1 − rate). Stacked discounts apply sequentially: sale = price × ∏(1 − rate_i). Effective rate = 1 − (sale / price). Tax-inclusive total = sale × (1 + tax).
• Browser API or library: Pure JavaScript arithmetic. No external library.
• Input limits: Any positive numeric price and rates from 0 to 100 percent. No hard cap on stacked discount count.
• Output: Sale price, total savings, effective percent off, and tax-inclusive total.
• Known limitations: No currency formatting beyond the chosen locale separator. Does not model BOGO, tiered, or fixed-amount-off promotions.

Frequently asked questions

How do I calculate the final price after a discount?

Final price = original price x (1 - discount percent / 100). A 50 dollar item with a 20 percent discount becomes 50 x 0.80 = 40 dollars. The calculator handles single discounts, stacked discounts, and an optional tax rate. Calculations are estimates for informational purposes only. Consult a financial professional for advice.

Is my price data sent to a server?

All calculations happen in your browser using simple arithmetic. Our servers are not involved at any point.

What is the difference between single, stacked, and double-discount modes?

Single mode applies one percentage. Stacked mode applies a list of percentages in sequence. Double-discount mode is a focused two-step view that highlights the effective rate of two consecutive discounts.

Why is a stacked 20 percent plus 10 percent not the same as 30 percent off?

Each subsequent discount applies to a smaller base price. A 20 percent discount followed by a 10 percent discount leaves 72 percent of the original price, an effective discount of 28 percent rather than 30 percent.

How does the tax option work?

Enter a tax rate and the calculator multiplies the sale price by one plus the rate to produce a tax-inclusive total alongside the pre-tax figure.

Can I use the calculator for negotiations or B2B quotes?

Yes. Enter the gross price and your standard discount rate, then add the tax rate to see the net price the customer pays.