Discounts on a GST invoice: before or after tax?
A discount agreed at the time of sale reduces the tax. One given later usually does not.
Last checked 20 September 2026
A discount given at or before the time of supply and recorded on the invoice reduces the taxable value, so you charge tax on the lower figure. A discount given after the sale only reduces the tax if it was agreed beforehand, is linked to specific invoices, and the buyer reverses the matching credit.
Discount on the invoice: reduces the tax
This is the ordinary trade discount, negotiated at the time of the sale and shown on the bill. It comes off the value, and GST is charged on what is left.
| Line | Amount |
|---|---|
| Gross value | ₹ 1,00,000 |
| Trade discount at 10% | − ₹ 10,000 |
| Taxable value | ₹ 90,000 |
| GST at 18% | ₹ 16,200 |
| Total | ₹ 1,06,200 |
Had the discount been given afterwards and not qualified, tax would have been ₹ 18,000 on the full ₹ 1,00,000 — ₹ 1,800 more, out of your margin.
GST Calculator — free, no signupAdd or remove GST at the new GST 2.0 rates. CGST/SGST or IGST split.Discount after the sale: conditional
Post-supply discounts — quarterly targets, year-end schemes, rate-difference claims — reduce the taxable value only if all of the following are true:
- The discount was agreed before or at the time of supply, under a documented arrangement.
- It can be linked to the specific invoices it relates to.
- The buyer reverses the input tax credit attributable to it.
Fail any of those and the discount is a commercial payment that does not reduce your GST. You give the money and keep the tax.
Write the scheme down before the quarter starts
The condition that fails most often is the first one. A target scheme that only exists in a conversation is not "agreed before the supply" in any way you can demonstrate. Put it in the dealer agreement or a dated circular.
How the adjustment is made
Through a credit note referencing the original invoices, declared within the time limit. Not by editing the original bill.
Free goods and schemes
A "10 + 1" scheme is not a discount in the tax sense — it is a quantity supplied for the price of ten. Treatment of free goods, bonus quantities and buy-one-get-one arrangements has been the subject of departmental clarification and is genuinely fiddly. Do not improvise it: get the treatment for your specific scheme confirmed.
Operationally, free units still leave your stock and still have a cost, so they belong on the invoice as their own column rather than being quietly written off.
Cash discount for early payment
An early-payment discount offered after the invoice is a post-supply discount, and runs into the same conditions. If you want it to reduce the tax, it has to be part of the terms established up front — which means the terms need to say so.
Margin is not the same as discount
A discount reduces what you charge. Your margin is what is left after cost. Discount 10% off a 12% margin and you have almost nothing left — worth checking before agreeing to it.
Margin & Markup Calculator — free, no signupWork out what a discount does to your margin before you offer it.Should the discount be per line or on the invoice total?
Either works, as long as the taxable value each line is taxed on is correct. Per line is clearer when lines carry different tax rates.
Can I show a discount as a negative line?
What matters is that the taxable value is right and the arithmetic is followable. A negative line that muddles which rate it applies to is asking for a query.
Does a discount affect the e-way bill value?
Consignment value is generally taken as the invoice value including tax. If a discount reduced the invoice, it reduced the consignment value with it.
Sources
- CGST Act 2017, section 15(3) — value of taxable supply
- CBIC — GST Acts, Rules and notifications (cbic-gst.gov.in)
Free tools for this
How TracEasy handles this
Related reading
GST invoice format: what must be on the bill
The fields Rule 46 requires, with a worked example of each.
Credit notes and debit notes under GST
How to undo or top up an invoice you have already issued, without deleting it.
What is billing, and what is an invoice?
The document that says what was sold, for how much, and what is now owed.