Most shop owners do not need to be GST experts, but they do need every bill their counter prints to be correct. A wrong rate, a missing GSTIN on a business customer's bill, or tax calculated on the wrong value creates problems at return filing time and in the customer's input tax credit. This practical guide to GST on retail bills covers what a counter bill should show, how tax is calculated on MRP-inclusive prices, how discounts and rounding work, the difference between B2C and B2B bills, and the POS settings to check. Detailed GST law, returns and edge cases belong with your accountant; this is the counter-level view.
The Current Rate Structure in Brief
GST rates were rationalised with effect from 22 September 2025. Most goods now fall into two main slabs, 5 percent and 18 percent, with a 40 percent slab for specified sin and luxury goods and nil rates for certain essentials. Many everyday retail items changed slabs at that time. Because rates are notified by HSN code and can be revised, keep these habits:
- Map every item in your POS to its HSN code and current rate, and check with your accountant or supplier invoices.
- Change rates in the item master on the effective date, so that bills before the date keep the old rate and bills after use the new one.
- Never edit old bills to apply a new rate.
What a Retail Tax Invoice Should Show
A tax invoice issued by a registered regular taxpayer generally includes:
- Supplier name, address and GSTIN.
- A unique, consecutive invoice number for the financial year (up to 16 characters, using letters, numbers, hyphens or slashes).
- Date of issue.
- Customer name and address, and GSTIN if the customer is registered. For unregistered customers, name and address are generally required when the taxable value is ₹50,000 or more.
- HSN code of goods, to the number of digits required for your turnover and type of supply.
- Description, quantity, unit and value of goods.
- Taxable value after discounts.
- Rate and amount of tax, shown as CGST and SGST for sales within the state, or IGST for inter-state supply.
- Place of supply with state name, for inter-state supplies.
- Signature or digital signature, or authentication by the system.
Confirm the exact current requirements with your accountant; the POS should print all of them without the cashier doing anything special.
Calculating Tax on MRP-Inclusive Prices
Retail prices in India are usually tax-inclusive. The POS must work backwards from the selling price to find the taxable value:
Taxable value = Selling price / (1 + GST rate)
| Item | Selling price (₹) | Rate | Taxable value (₹) | CGST (₹) | SGST (₹) |
|---|---|---|---|---|---|
| Biscuit pack | 52.50 | 5% | 50.00 | 1.25 | 1.25 |
| Shampoo | 236.00 | 18% | 200.00 | 18.00 | 18.00 |
| Steel tumbler | 105.00 | 5% | 100.00 | 2.50 | 2.50 |
A common mistake is adding tax on top of an inclusive price, so a ₹236 item is billed at ₹278.48. Check a few bills during setup to make sure prices are flagged correctly as inclusive or exclusive.
Discounts and Free Items
A discount shown on the invoice at the time of sale reduces the taxable value. Suppose a ₹1,180 item (18 percent inclusive) is sold with a 10 percent discount. The customer pays ₹1,062. Taxable value is ₹1,062 / 1.18 = ₹900, with ₹81 CGST and ₹81 SGST.
For "buy one get one free" and combo offers, the common approach is to treat the offer as a discount spread across the items, so the total taxable value is what the customer pays. The tax treatment of free items and post-sale discounts has specific rules, so set promotions up the way your accountant advises, and let the POS apply them consistently.
Note that for apparel and footwear, where the rate depends on the price per piece, a discount can change the applicable slab. Your POS should decide the rate on the final selling price per piece.
Rounding Off
Bills are usually rounded to the nearest rupee, with the rounding shown as a separate line. Tax should be calculated on the actual taxable value before rounding, and the round-off line should not carry tax. Rounding totals from many bills should net out close to zero over a month; if it does not, the POS rounding rule may be biased.
B2C vs B2B Bills at the Counter
Retail counters serve mostly unregistered consumers (B2C), but businesses also buy: a cafe buying supplies, a contractor buying hardware. For B2B sales:
- Capture the buyer's GSTIN, legal name and address on the bill.
- Check the GSTIN state code; it affects whether CGST and SGST or IGST applies only when the place of supply is outside your state. For goods sold over the counter, the place of supply is generally your store location.
- If your aggregate turnover crosses the e-invoicing threshold, B2B invoices must be reported to the invoice registration portal and carry an IRN and QR code.
A good POS lets the cashier search or add a business customer quickly, and stores the GSTIN for next time.
Small Value Sales and Consolidated Invoices
GST rules allow a registered person to issue a consolidated tax invoice at the end of the day for supplies below a small value (₹200) to unregistered customers who do not ask for an invoice. In practice, most POS-run stores print a bill for every sale anyway, because it helps stock control and customer trust. If you do use consolidated invoices, make sure your POS still records each sale.
Composition Scheme Dealers
If you are registered under the composition scheme, you pay tax at a fixed percentage of turnover and cannot collect GST from customers. Your bills must be a bill of supply, not a tax invoice, and generally carry a statement that you are a composition taxable person not eligible to collect tax. Configure the POS to print no tax lines. Composition has turnover limits and conditions, so check eligibility with your accountant.
Bills With Items at Several Rates
A typical grocery bill mixes nil-rated, 5 percent and 18 percent items. The bill should show the rate against each item (or a code that points to a rate) and a tax summary at the bottom grouping taxable value and tax by rate. For example:
| Rate | Taxable value (₹) | CGST (₹) | SGST (₹) |
|---|---|---|---|
| Nil | 180.00 | 0.00 | 0.00 |
| 5% | 640.00 | 16.00 | 16.00 |
| 18% | 350.00 | 31.50 | 31.50 |
The summary helps your accountant at month end and helps a business customer claim credit correctly.
A Rate Change Day Checklist
When rates change, as they did in September 2025, the switch happens at midnight on the effective date. A simple checklist:
- Get the list of affected HSN codes and new rates from your accountant a few days before.
- Prepare the item master changes in advance, scheduled for the effective date if your software supports it.
- Close all shifts and the day before the effective date.
- Apply changes before the first bill of the new day, and check five sample bills.
- Review shelf prices: if MRP-inclusive prices change, labels may need updating under the applicable rules for revised MRP.
POS Settings Checklist
- GSTIN, legal name and address correctly set on the bill header.
- Invoice series per financial year and per counter, with no manual numbering.
- Every item mapped to an HSN code and current rate.
- Inclusive or exclusive pricing set correctly per item or price list.
- Discounts applied before tax calculation.
- Rounding line without tax.
- Business customer GSTIN capture for B2B bills.
- Bill of supply format if under composition.
- Credit notes linked to original bills for returns.
For returns and credit notes at the counter, see how to handle returns and exchanges.
Common Counter Mistakes
- Tax added on top of an MRP-inclusive price.
- Old rates left in the item master after a rate change.
- B2B bills printed without the buyer's GSTIN.
- Manual invoice numbers or a series restarted mid-year.
- Returns processed without linking to the original bill.
Practical Questions Owners Ask
Can I restart invoice numbers every month?
Invoice numbers must be unique for a financial year within each series, so numbering should not restart monthly. Separate series per counter or store are fine, and most POS systems handle this automatically.
What should I do when a GST rate changes?
Update item rates in the POS on the effective date, close the previous day properly, check a few sample bills, and never edit earlier bills. Confirm the affected items and new rates with your accountant beforehand.
How Fininvo Fits
Fininvo ERP handles GST-ready invoicing, and its Retail & POS workspace includes e-invoice and e-way bill pages for counter-related compliance, posting into the same books. See pricing for plans.
Frequently Asked Questions
Is GST included in MRP?
Yes. MRP in India is inclusive of all taxes. The POS calculates the taxable value by dividing the selling price by one plus the GST rate.
Do I need to give a GST bill for every sale?
A registered business generally issues a tax invoice for each supply, with a provision for a daily consolidated invoice for small-value sales to unregistered customers who do not request one. Most POS-run stores bill every sale.
When is the customer's name required on a retail bill?
For unregistered customers, name and address are generally required when the taxable value is ₹50,000 or more. For registered business customers, their GSTIN and details should always appear.
Does a discount reduce GST?
A discount shown on the invoice at the time of sale reduces the taxable value, so tax is calculated on the discounted price.
Can a composition dealer charge GST on bills?
No. Composition dealers issue a bill of supply without tax and pay tax on turnover at the composition rate.
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