How to Create a GST Invoice in India: Complete Guide for Freelancers

If you're a freelancer or small agency in India who's just crossed the GST registration threshold — or you've been registered for a while but still feel unsure whether your invoices are truly compliant — this guide covers everything you need to know. No jargon. Just the rules, the numbers, and exactly what to write on every invoice.

Who Needs to Issue GST Invoices?

You are required to register for GST and issue GST-compliant invoices if your aggregate annual turnover exceeds ₹20 lakh (₹10 lakh for special category states: Manipur, Mizoram, Nagaland, Tripura). If you provide services exclusively, this threshold applies.

Even if you're below the threshold, some clients — particularly corporates and agencies — may require a GST invoice to claim input tax credit (ITC). In that case, voluntary GST registration is worth considering.

Mandatory Fields on a GST Invoice

Under Rule 46 of the CGST Rules, 2017, a tax invoice must contain these fields. Missing even one can make the invoice invalid for your client's ITC claim — and for your own record-keeping.

CGST + SGST vs IGST: When Each Applies

This is the question that trips up most freelancers. The rule is simple:

• Intra-state supply (you and your client are in the same state): charge CGST + SGST, each at half the GST rate. For 18% GST → CGST 9% + SGST 9%.
• Inter-state supply (you and your client are in different states): charge IGST at the full GST rate. For 18% GST → IGST 18%.
• Export of services (client is outside India): zero-rated supply, IGST 0%. You can claim a refund of input tax credit paid on inputs.

Example: You're a freelancer in Maharashtra (GSTIN starts with 27). Your client is in Karnataka (GSTIN starts with 29). This is inter-state → charge IGST 18%. If the same client was also in Maharashtra → charge CGST 9% + SGST 9%.

SAC Codes for Common Freelance Services

SAC (Service Accounting Code) is a 6-digit code that classifies services for GST purposes. Your invoice must include the correct SAC for your services.

GST Invoice Due Dates

You must issue the GST invoice within the time limits below. Late invoices can attract penalties and create problems for your client's ITC claim.

Step-by-Step: Create a GST-Compliant Invoice

Step 1 — Gather your information

Before you start, have ready: your GSTIN, your client's GSTIN (ask them), both addresses, the SAC code for your service, the invoice date, and the agreed fee.

Step 2 — Calculate GST correctly

Determine whether the supply is intra-state or inter-state by comparing your state with your client's state (look at the first two digits of both GSTINs — if they match, it's intra-state). Then apply CGST + SGST or IGST accordingly.

Step 3 — Assign a sequential invoice number

Your invoice number must be unique within a financial year (April–March). A simple format likeINV-2026-001 works. Once you issue invoice 001, the next must be 002 — gaps in the sequence are technically allowed but can raise questions during GST audit.

Step 4 — Use a GST invoice tool or template

You can use ClearWork's free GST Invoice Generator — it auto-detects intra/inter-state based on your state and client state, calculates CGST/SGST/IGST correctly, and generates a print-ready PDF you can email directly.

Common Mistakes to Avoid

• Wrong tax type: Charging CGST+SGST for an inter-state client (or IGST for intra-state) is the #1 error. Your client can't claim ITC on incorrectly-structured GST.
• Missing GSTIN: If your client is GST-registered and you omit their GSTIN, they can't claim ITC — they'll ask you to reissue.
• Invoice date after payment: The invoice must be issued before or on the date of payment, or within 30 days of service completion — whichever is earlier.
• Incorrect SAC code: A wrong SAC code can mismatch with your GST returns (GSTR-1) and trigger notices.
• Amount mismatch: The total in figures must match the total in words (amount in words is mandatory). A mismatch invalidates the invoice.
• No place of supply: This field is mandatory and determines which tax applies. Don't skip it.

GST Invoice for Exports (If Your Client Is Overseas)

If you work with international clients (US, UK, EU companies etc.), your services qualify as "export of services" under GST — provided payment is received in foreign currency through banking channels. These are zero-rated supplies: you charge 0% GST (IGST 0%) and can claim a refund of any GST paid on your inputs (software subscriptions, equipment, etc.).

On your export invoice, write "Supply meant for export / zero-rated supply" in the description. Include the client's address and country. No GSTIN required for foreign clients.