Discount calculator
Discount calculator is a finance tool that works out sale price, savings, and the effective percent off from any combination of discounts. It supports single, stacked, and double-discount modes, includes an optional sales-tax rate, and updates results as you type. The tool runs in your browser.
Result
- Sale price
- 80.00
- You save
- 20.00
- Effective discount
- 20%
Calculations are estimates for informational purposes only. Consult a financial professional for advice.
All calculations run entirely in your browser.
Dedicated pages
Direct links for specific discount workflows.
Discount Calculator
Calculate sale price, savings, and effective percent off from a single discount or a stack of discounts. All calculations run in your browser.
Percent Off Calculator
Calculate the sale price and savings from a percent-off discount. Add a tax rate for the tax-inclusive total. Runs entirely in your browser.
Sale Price Calculator
Work out the sale price after a percent-off discount. Compare single and stacked discounts side by side. All processing runs in your browser.
How to calculate a discount
- Enter the original price.
- Enter one or more discount percentages depending on the mode.
- Add a sales-tax rate for a tax-inclusive total if you need one.
- Read the sale price, savings, and effective percent off in the result panel.
Common uses
- Comparing seasonal promotions or two competing offers side by side
- 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. All calculations run in your browser.
- 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.
Reviewed and tested May 26, 2026.