GST Invoice Checklist for Freelancers and Service Businesses

A GST invoice isn't just a bill — it's a legal document. If it's missing mandatory fields, your client can't claim Input Tax Credit on it, and you could face penalties during an audit. This checklist covers every field your tax invoice must contain under the CGST Rules, written specifically for freelancers, consultants, and service businesses billing from India.

1. Your GSTIN. Your 15-digit Goods and Services Tax Identification Number must appear on every invoice. It's tied to your PAN and state code. If you operate from multiple states, you'll have a separate GSTIN for each state. Double-check the number — a typo here invalidates the entire invoice for ITC purposes.

2. Invoice number. Must be unique and sequential within a financial year. You can use any format (INV-001, PC-2025-001, etc.) but it cannot repeat. Gaps in sequence are technically allowed but raise flags during audits. Most invoicing tools handle this automatically. If you manage numbering manually, keep a register.

3. Date of issue. The date on the invoice determines which return period it falls into. For services, the invoice must be issued within 30 days of the date of supply. If you deliver work on March 28 but invoice on April 5, that invoice belongs to the April filing period.

4. Client's name, address, and GSTIN. If your client is GST-registered, their GSTIN is mandatory. If they're unregistered (common with individual clients or foreign companies), note "Unregistered" or "N/A" in the GSTIN field. Get the legal entity name exactly right — "Acme Pvt Ltd" is different from "Acme Private Limited" in the GST system.

5. Place of supply. This determines whether you charge IGST or CGST+SGST. For services, the default place of supply is the location of the recipient. If your client's billing address is in Maharashtra and you're registered in Maharashtra, it's intra-state (CGST+SGST). If the client is in Karnataka, it's inter-state (IGST). For exports, the place of supply is outside India.

6. SAC code. The Services Accounting Code classifies your service type. Common codes for freelancers: 998314 (IT design and development), 998361 (management consulting), 998312 (computer programming), 998397 (other professional services). You can look up SAC codes on the CBIC website. Using an incorrect code doesn't immediately cause problems, but it can trigger notices during detailed audits.

7. Description of service. Be specific enough that an auditor can understand what was delivered. "Web development services — Phase 2, March 2025" is better than "Professional services." If you have multiple line items, describe each one separately with individual amounts.

8. Taxable value. The value of services before tax. This is the base amount on which GST is calculated. If you offer discounts, show the original amount and the discount separately — the taxable value is the net after discount.

9. Tax rate and amount. Show the applicable rate (usually 18% for services) and the tax amount. For intra-state: show CGST at 9% (₹X) and SGST at 9% (₹X) separately. For inter-state: show IGST at 18% (₹X). The total of taxable value + tax = invoice total. This split is not optional — lumping everything together makes the invoice non-compliant.

10. Total invoice value. The final amount including tax, written in both figures and words. "₹1,18,000 (Rupees One Lakh Eighteen Thousand Only)" is the standard format. This seems old-fashioned but it's a legal requirement for tax invoices above a certain threshold.

11. HSN/SAC code on each line item. If your aggregate annual turnover exceeds ₹5 crore, you need the SAC code on every line item. Below that threshold, it's technically optional but strongly recommended. Including it avoids any classification disputes and makes your invoices more professional.

12. Reverse charge applicability. If the service falls under reverse charge mechanism (RCM), the invoice must explicitly state "Tax payable under reverse charge." Most freelancer services don't fall under RCM, but certain categories like legal services, sponsorship services, and GTA services do. When in doubt, check with your CA.

13. Your signature. A physical or digital signature (including a digital signature certificate) validates the invoice. For PDF invoices sent electronically, a scanned signature or DSC-based signature works. Unsigned invoices are technically incomplete under GST rules.

Common mistakes to avoid: Using your old pre-GST invoice format. Forgetting to update the SAC code when your service mix changes. Issuing invoices with dates in the wrong financial year. Not mentioning "export of services" or "supply to SEZ" when applicable. Charging IGST on intra-state supply or vice versa.

PropCraft's invoice generator handles all 13 of these fields automatically. Enter your client's GSTIN and state, and it determines the correct tax type, calculates the split, and generates a PDF that passes compliance checks. It won't file your returns for you, but it makes sure every invoice you send is audit-ready. Try the GST invoicing workflow.