Value of Supply under GST — How Tax is Calculated

GST ACT SIMPLIFIED SERIES

GST is charged as a percentage of the 'value of supply' — but that value isn't always simply the sale price written on your invoice. Section 15 of the CGST Act lays out precisely what must be included and what can be excluded when arriving at the taxable value.

The Transaction Value Rule

Under Section 15, the value of supply is the 'transaction value' — the price actually paid or payable for the supply of goods or services — provided two conditions are met: the supplier and recipient are not related persons, and the price is the sole consideration for the supply. This transaction-value approach is the default and most commonly used method of valuation under GST.

What Gets Added to the Value

•      Any taxes, duties, cesses, fees and charges levied under any law other than GST itself, if charged separately by the supplier

•      Any amount that the supplier is liable to pay in relation to the supply but which has actually been incurred by the recipient, and is not already included in the price

•      Incidental expenses such as packing, commission, and any amount charged for anything done by the supplier at the time of, or before, delivery

•      Interest, late fee, or penalty charged by the supplier for delayed payment of any consideration for the supply

•      Subsidies directly linked to the price, excluding subsidies provided by the Central Government or State Governments

What Gets Excluded from the Value

•      Discounts given before or at the time of supply, provided such discount is duly recorded/shown in the invoice issued for the supply

•      Post-supply discounts, but only if: they were established under an agreement entered into at or before the time of supply, they can be specifically linked to the relevant invoices, and the recipient reverses the input tax credit attributable to the discount

Special Valuation Rules for Non-Standard Transactions

When the transaction-value rule cannot be applied — such as transactions between related parties, transactions where consideration is not wholly in money (like barter or exchange deals), or supply through an agent — Rules 27 to 31 of the CGST Rules prescribe alternative valuation methods, generally based on the open market value of the supply, or the value of a supply of like kind and quality, or a computed cost-plus-margin approach as a last resort.

For related-party transactions specifically, if the recipient is eligible for full ITC, the value declared in the invoice is deemed to be the open market value, removing the need for detailed valuation exercises purely for revenue-neutral internal transactions.

💡  Illustration — Basic Value of Supply Computation

A product with an MRP of ₹10,000 is sold with a trade discount of ₹1,000 shown on the invoice, plus ₹200 charged separately for packing. The value of supply for GST purposes = ₹10,000 − ₹1,000 + ₹200 = ₹9,200, and GST is calculated on this ₹9,200, not on the original MRP or the discounted price alone.

💡  Illustration — Post-Supply Discount Treatment

A distributor agrees with a manufacturer, at the time of the original sale agreement, that a 5% volume discount will be given at year-end if annual purchases cross a target. When the target is met, the manufacturer issues a credit note linked to the specific invoices for that discount. Since the discount was pre-agreed, is linked to specific invoices, and the distributor reverses the proportionate ITC, this discount can be validly excluded from the taxable value — had any of these three conditions been missing, GST would still apply on the pre-discount value.

⚠  Common Mistakes to Avoid

•  Charging GST on the MRP without adjusting for legitimate discounts that are clearly recorded on the invoice

•  Not reversing proportionate ITC when passing on a post-sale discount to a customer via credit note, which is a mandatory condition for excluding that discount from taxable value

•  Excluding packing, forwarding, or other incidental charges from the taxable value when they should be included as part of the composite supply

•  Ignoring special valuation rules for related-party or barter transactions and simply using an arbitrary internal transfer price

Frequently Asked Questions

Q1. Is GST charged on the discount amount?

A. No — genuine discounts recorded on the invoice, or pre-agreed post-sale discounts properly linked to specific invoices with corresponding ITC reversal, are excluded from the taxable value.

Q2. Is GST payable on free samples given to customers?

A. Generally, no GST is charged on goods given as free samples since there's no consideration involved, but the supplier also cannot claim ITC on inputs used to make those samples.

Q3. Does the value of supply include packing and forwarding charges?

A. Yes, incidental expenses like packing charges that are part of the supply, charged by the supplier before or at the time of delivery, are includible in the value of supply.

Q4. How is GST valued for transactions between related parties, like group companies?

A. Special valuation rules apply, generally based on open market value, though if the recipient is entitled to full ITC, the invoice value itself is deemed acceptable as the open market value for practical purposes.

Q5. Is interest charged for late payment by a customer subject to GST?

A. Yes, interest, late fee, or penalty charged for delayed payment of consideration is specifically includible in the value of supply and is subject to GST.

Q6. What happens if a discount is given after supply but wasn't pre-agreed at the time of sale?

A. Such a discount cannot be excluded from the taxable value for GST purposes; the supplier may still issue a commercial credit note for accounting purposes, but the original GST liability on the full pre-discount value remains unchanged.

✓  Key Takeaways

•  Value of supply is generally the transaction value — the actual price paid or payable, adjusted per Section 15

•  Incidental charges, government-unrelated subsidies, and late-payment interest get added to the taxable value

•  Discounts are excluded only if properly disclosed on the invoice, or pre-agreed and linked to specific invoices with ITC reversal

•  Special valuation rules (open market value, similar-supply value) apply for related-party or non-monetary-consideration transactions

Note: GST rates, thresholds and procedures are revised periodically by the GST Council and CBIC. This article reflects the position understood as of the GST 2.0 rate structure (effective 22 September 2025). Please verify current figures on www.gst.gov.in or with a qualified tax professional before making compliance decisions.

Disclaimer

This content is shared strictly for general information and knowledge purposes only. Readers should independently verify the information from reliable sources. It is not intended to provide legal, professional, or advisory guidance. The author and the organisation disclaim all liability arising from the use of this content. The material has been prepared with the assistance of AI tools.