How to use the discount calculator
- Enter the original price and the discount, either as a percentage (tap a preset) or as a fixed amount off.
- Add a second discount if the shop offers “extra 10% off on discounted items”, and switch on tax if it is charged after the discount.
- Read the final price, the amount saved and the overall percentage off. The formula with your numbers is shown underneath.
- Use “Original price” mode when you know the price you paid and the discount, and want to know the list price.
Features
- Percentage or fixed-amount discounts with common presets
- Stacked second discount with the true combined percentage
- Optional tax (GST, VAT, sales tax) applied after the discount
- Reverse mode: find the original price from the sale price
- Amount saved and the formula shown for every calculation
The discount formulas
Discounts are percentages of the price they are applied to:
- Sale price = original × (1 − discount ÷ 100). Example: 2,499 at 20% off = 2,499 × 0.8 = 1,999.20, saving 499.80.
- Fixed amount off: sale price = original − amount.
- Stacked discount: apply the second percentage to the already reduced price. 50% off then an extra 10% off is 55% off in total, not 60%.
- Tax after discount: final = sale price × (1 + tax ÷ 100). Tax is charged on what you actually pay.
- Reverse: original = sale price ÷ (1 − discount ÷ 100). If you paid 800 after 20% off, the original was 1,000.
Why stacked discounts are less than they look
A second discount applies to the reduced price, not the original. “40% off + extra 25% off” sounds like 65% but is 1 − 0.6 × 0.75 = 55%. The tool shows the effective overall percentage so you can compare offers honestly. Prices are rounded to two decimals; shops may round differently, so expect small differences of a paisa or cent.