Compliance · 10 min read

The 2026 guide to GST + e-invoice billing for Indian pharmacies

Published 18 May 2026

GST compliance for a pharmacy isn't just GSTR-1 and GSTR-3B anymore. Since 2024 the e-invoice (IRN) threshold has dropped to ₹5 Cr turnover, e-way bills are mandatory for inter-state goods movement above ₹50,000, and drug-licence renewals are tied to your tax filings under the Drugs and Cosmetics Act. Miss one and you don't just pay a late fee — you risk a notice that asks why your stock register doesn't match your sales register.

This guide walks through the four compliance regimes a typical Indian chemist deals with, what the deadlines actually are, and how PharmOS automates each one so your CA doesn't spend the first weekend of every month chasing exports.

1. GSTR-1 and GSTR-3B

GSTR-1 is your monthly outward-supplies return (sales). Due on the 11th of the next month for monthly filers, or quarterly for the QRMP scheme. It reports every B2B invoice, B2C-large invoice (₹2.5 lakh+ inter-state), exports, and credit notes.

GSTR-3B is your monthly summary return. Due on the 20th of the next month. It reports the total taxable value, output tax (IGST / CGST / SGST), input tax credit (ITC), and net tax payable.

Most pharmacies struggle here not because the math is hard but because exporting bill-level data from a desktop ERP requires either an integration or a fortnight of Excel work. PharmOS generates GSTR-1 and GSTR-3B in both JSON (direct GSTN upload format) and CSV. You log into the GSTN portal, upload the JSON, validate, file.

2. e-invoice (IRN)

If your aggregate turnover exceeds ₹5 Cr in any preceding financial year, every B2B invoice must be reported to the Invoice Registration Portal (IRP) to obtain an Invoice Reference Number (IRN) and a QR code, before you send the invoice to the customer.

The IRN must be generated within 30 days of the invoice date for the invoice to be valid. After 30 days, IRP rejects the request and you have to issue a credit note + new invoice — painful, and customers don't love it.

PharmOS integrates the NIC GSP scaffold so IRN generation is a one-click action at bill time (or batched at end-of-day). The QR code prints on the invoice; you don't need a separate IRN tool.

3. e-way bill

Required for inter-state goods movement above ₹50,000 (some states have lower intra-state thresholds). The e-way bill carries a 12-digit number that must accompany the goods until delivery.

For pharmacies, e-way bills typically come up for stock transfers between branches (multi-store chains) and for high-value distributor orders. PharmOS generates e-way bills via the NIC GSP scaffold the moment the dispatch is recorded.

4. Drug-licence compliance

Under the Drugs and Cosmetics Act, you need a valid 20B (retail) or 21B (wholesale) drug licence to operate, plus a Schedule H1 narcotics register if you sell those drugs.

The licence is typically valid for 5 years and must be renewed before expiry. State inspectors do random audits, especially around year-end, and an expired DL is a quick way to get your store sealed for 90 days.

PharmOS tracks your own DL plus every supplier DL and distributor DL you onboard, with renewal alerts at 30 / 14 / 7 / 0 days before expiry. The Schedule H1 register is built-in with read/write API for audit prints.

5. GSTR-2A / 2B reconciliation

GSTR-2A is an auto-populated read-only return showing inward supplies based on what your suppliers filed in their GSTR-1. GSTR-2B is the same data, but with eligibility tags for ITC.

To claim ITC correctly, you need to reconcile your purchase ledger against GSTR-2A / 2B every month. Mismatches happen — supplier files late, types wrong GSTIN, or forgets to file — and unreconciled ITC means you pay more GST than you owe.

PharmOS imports GSTR-2A / 2B JSON from the GSTN portal and auto-matches against your purchase ledger. Mismatches surface with a one-click "notify supplier on WhatsApp" action.

6. FY close and audit trail

At year-end you lock the financial year, post closing journals, carry opening balances forward to the new year, and reconcile trial balance. For most pharmacies this is the worst weekend of the year because the desktop ERP doesn't make any of it easy.

PharmOS has a dedicated FY-close screen: lock FY, post closing journals, generate opening-balance carry-forward entries, run trial balance, export to Tally Prime XML for your CA. Reopens are supported (one-click) if you find a missed entry post-lock.

7. Bank reconciliation

Not strictly a GST requirement, but bank recon is what your CA does to validate every transaction in your books. PharmOS auto-detects HDFC / ICICI / SBI / Axis CSV formats with a configurable match threshold (default 90/100). Unmatched lines surface for review.

8. Late fees and penalties

Missing GSTR-1 attracts ₹200/day late fee (₹100 each CGST + SGST), capped at ₹5,000 per return. Missing GSTR-3B attracts the same + interest on tax dues. e-invoice mandatory but not generated: invoice is treated as invalid and you may lose ITC eligibility for the recipient.

PharmOS has a GST late-fee calculator built-in so you know the cost of slipping a deadline before you slip it.

Bottom line

India's GST + drug-licence regime isn't getting simpler, but it's entirely automatable with the right software. PharmOS handles GSTR-1 + 3B, e-invoice IRN, e-way bills, drug-licence tracking, GSTR-2A/2B reconciliation, FY close and bank recon as native features — not bolt-ons. Most pilots have cut their monthly CA-prep time from 12 hours to under 2.