Discount calculator for shoppers and sellers
Whether you are checking a "Flat 40% + extra 10%" festive offer or setting a trade discount for a dealer, this calculator gives the exact final price, the rupee saving and the effective percentage. It also handles GST correctly — as a tax included in the MRP for retail or added after discount for B2B invoices.
Formulas
- Price after discount = MRP × (1 − d%)
- Successive discounts: Price = MRP × (1 − d1) × (1 − d2)
- Effective discount % = 1 − (1 − d1)(1 − d2) → 20% + 10% = 28%, not 30%
- Saving = MRP − Final Price
- GST on invoice discount: taxable value = discounted price; GST = taxable value × rate
Worked example
A jacket has MRP ₹2,499. The store offers 20% off and a card gives a further 10%. After the first discount: 2,499 × 0.80 = ₹1,999.20. After the second: 1,999.20 × 0.90 = ₹1,799.28. Total saving ₹699.72, which is 28% — not the 30% many shoppers assume. Because the MRP includes 12% GST on apparel, the taxable value inside ₹1,799.28 is ₹1,606.50 and GST is ₹192.78.
Why successive discounts are less than their sum
The second discount is applied to the already-reduced price, so it is worth less in rupees than the same percentage on the full MRP. Retailers use "40% + 20%" because it reads like 60% but costs them only 52%. Always check the effective rate before deciding an offer is good.
GST treatment of discounts (for sellers)
Under Section 15(3) of the CGST Act, a discount shown on the face of the invoice is deducted before charging GST. So on a ₹10,000 B2B supply with 10% trade discount, GST at 18% is charged on ₹9,000, not ₹10,000. Post-sale discounts (year-end turnover incentives) can be reduced from the taxable value only if agreed in advance and linked to specific invoices, with the buyer reversing proportionate input credit via a credit note.
Features
- Two successive percentage discounts plus a flat coupon
- GST inclusive (retail MRP) or GST added (B2B) modes, with CGST/SGST split
- Quantity multiplier for bulk purchases
- Quick table showing the same MRP at 5–70% off
Frequently Asked Questions
Is 20% + 10% the same as 30% off?
No. 20% + 10% applied one after the other equals 28% off. The second discount acts on a smaller base.
Is GST charged before or after discount?
For discounts shown on the invoice, GST is charged on the discounted value. Retail MRP already includes GST, so a discount on MRP reduces both the price and the tax proportionately.
How do I calculate the discount percentage from two prices?
Discount % = (MRP − Sale Price) ÷ MRP × 100. For ₹2,499 reduced to ₹1,799: 700 ÷ 2,499 = 28%.
Can a shop charge GST over the MRP?
No. MRP is inclusive of all taxes under the Legal Metrology (Packaged Commodities) Rules. Charging GST on top of MRP is illegal and can be reported to consumer affairs.
Disclaimer: This tool is for general information and estimation only. Tax rates and rules change — verify with official sources or a professional before acting. Read full disclaimer.