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GST registration comes with a subscription you can't cancel: returns. File them on time and GST is mostly painless plumbing; miss them and late fees accumulate daily, your clients' input credit gets blocked, and eventually your registration itself is at risk. The system looks intimidating — GSTR-1, 3B, 9, 2B, QRMP — but a small service business really only needs to understand two forms and one scheme.
The two returns that matter
GSTR-1 — what you sold. The detailed list of your outward supplies (invoices) for the period: B2B invoices with client GSTINs, B2C summaries, credit notes. This is the return your clients care about — their input tax credit appears in their GSTR-2B only after your GSTR-1 shows the invoice. File late and every registered client's accountant notices.
GSTR-3B — the summary and the payment. A self-declared summary of sales, ITC claimed, and tax payable — filed with payment. This is where money actually moves.
Everything else is periodic housekeeping: GSTR-9 (annual return — optional below ₹2 crore turnover), and auto-generated views like GSTR-2B (your purchases, as reported by suppliers — the thing you reconcile ITC against).
Monthly or quarterly? The QRMP decision
If your turnover is up to ₹5 crore, the QRMP scheme (Quarterly Return, Monthly Payment) lets you file both returns quarterly while paying tax monthly by challan (fixed-sum 35% method or self-assessment). For a freelancer or studio issuing a handful of invoices, quarterly filing cuts compliance touchpoints from ~24 a year to ~12.
The trade-off: B2B clients see your invoices in their 2B only quarterly — unless you use the IFF (Invoice Furnishing Facility) to push B2B invoices monthly. If your clients are corporates who chase credits, IFF keeps them happy while you stay quarterly.
Due dates at a glance
| Return | Monthly filers | QRMP |
|---|---|---|
| GSTR-1 | 11th of next month | 13th of month after quarter |
| GSTR-3B | 20th of next month | 22nd/24th of month after quarter (state-dependent) |
| Payment | with 3B | monthly, 25th (PMT-06) |
What late filing actually costs
- Late fee: ₹50/day (₹25 CGST + ₹25 SGST) per return, ₹20/day for nil returns — capped based on turnover, but it compounds across periods fast
- Interest: 18% p.a. on tax paid late
- Blocked e-way bills after two unfiled periods; GSTR-1 blocked if 3B is pending
- Registration cancellation for six months of continuous non-filing (regular filers)
- The soft cost: clients whose ITC doesn't appear stop being your clients
Nil returns are still returns. No sales this quarter? File the nil return — the late fee applies regardless of tax due. Seasonal wedding businesses trip on this constantly in the off-season.
A one-hour filing routine
For a service business with modest invoice volume:
- During the period: number invoices sequentially, record every one somewhere structured — this is the raw material of GSTR-1. (Invoice numbering rules)
- Before filing 3B: open GSTR-2B, match your purchase invoices against it, claim only ITC that appears there. A supplier who didn't file = credit you can't take yet — chase them. (How ITC works)
- File GSTR-1 from your invoice register — with clean records this is data entry, 20 minutes
- File GSTR-3B, pay the balance after ITC
- Advances note: service advances are taxable when received — they go into the return for the month you got the booking money, not the event month. (Receipt voucher rules)
Most small businesses hand this hour to a CA for ₹1,000–2,500/month — reasonable. But the CA's output is only as good as your records: a shoebox of screenshots costs you more in their time (and missed ITC) than clean books do.
Keep the raw material clean
Every GST filing pain traces back to invoice-time habits. BrightDesk's GST invoice generator keeps invoices compliant and sequentially numbered as you issue them, and BrightDesk holds the invoice register — amounts, dates, clients, payment status — your filings are built from. Start with GST registration basics if you're not yet registered, or the composition scheme guide if quarterly 1%-of-turnover simplicity sounds better than the ITC game.