GST Invoice Format for Indian Freelancers: What Must Be on Every Invoice

You've completed the project. The client is happy. Now you need to send the invoice.

If you're GST-registered, this invoice isn't just a payment request — it's a legal document that your client uses to claim Input Tax Credit from the government. Get it wrong, and your client can't claim their ITC, they come back to you with complaints, and your professional credibility takes a hit.

This guide covers exactly what must be on your GST invoice, how to handle intra-state vs inter-state billing, and the common mistakes freelancers make.

Who Needs to Issue a GST Invoice?

First, a quick check. You only need to issue a GST-compliant "Tax Invoice" if you are registered under GST. This typically means your annual service income exceeds ₹20 Lakhs (₹10 Lakhs in special category states).

If you're below the threshold and haven't voluntarily registered, you should issue a "Bill of Supply" instead — a simpler document that doesn't include GST. Don't label it "Tax Invoice" if you're not registered.

The 8 Mandatory Fields on Every GST Tax Invoice

Indian GST law (specifically Rule 46 of the CGST Rules) mandates that every tax invoice must contain the following:

1. The Words "Tax Invoice" at the Top

This might sound obvious, but it must be explicitly written. Not "Invoice," not "Bill," not "Receipt" — the words "Tax Invoice" must appear clearly at the top of the document.

2. Your Details as the Supplier

• Your full legal name (as it appears on your GST registration)
• Your registered business address
• Your 15-digit GSTIN (GST Identification Number)

If you're a sole proprietor freelancer, this will be your personal name and address.

3. Client Details

• Client's name and business address
• Client's GSTIN (if they are GST-registered)

If your client is not GST-registered (an individual, for example), you still include their name and address, but the GSTIN field can be left blank. The invoice is still valid.

4. Unique Invoice Number and Date

Every invoice must have a sequential, unique invoice number within a financial year. You cannot reuse numbers or skip numbers. The most common format freelancers use:

EL/2025-26/001 (for the 1st invoice of FY 2025-26) EL/2025-26/002 (for the 2nd invoice)

And so on. The series resets at the start of each financial year.

The date must be the date on which you're raising the invoice — not backdated to when the work was completed (unless within the same month).

5. SAC Code

SAC stands for Services Accounting Code — a classification code for your type of service, similar to HSN codes for goods. Every service invoice must include the relevant SAC code.

Common SAC codes for freelancers:

When in doubt, check the CBIC GST rate finder or ask your CA.

6. Description of Services

A clear description of what you provided. Not just "Services rendered" — something specific like "Website development for e-commerce portal — Phase 1" or "Tax filing assistance for FY 2024-25."

The more specific, the better — it helps your client's accounts team categorize the expense, and it helps you if there's ever a dispute.

7. Tax Breakdown — CGST/SGST or IGST

This is where many freelancers go wrong. The tax split depends on whether your client is in the same state as you or a different state.

Same State (Intra-state): Split the GST into CGST and SGST equally.

• Example: 18% GST → 9% CGST + 9% SGST

Different State (Inter-state): Apply the full GST as IGST (Integrated GST).

• Example: 18% GST → 18% IGST (not split)

The determination is based on your registered GST state and your client's delivery address (or place of supply for services).

8. Total Amount (Figures and Words)

The final invoice total — base amount + GST — must be written in both numerals and words. This is a legal requirement, not just a formality.

A Complete Invoice Example

Rajan is a freelance software developer registered in Pune, Maharashtra. He completes a ₹80,000 project for a startup in Bangalore, Karnataka (inter-state).

                         TAX INVOICE

Invoice No: RJ/2025-26/018          Date: 15 May 2026

Supplier:                           Recipient:
Rajan Kumar                         TechStart Solutions Pvt Ltd
123, Kothrud, Pune - 411038         456, Koramangala, Bengaluru - 560034
Maharashtra                         Karnataka
GSTIN: 27ABCDE1234F1Z5              GSTIN: 29FGHIJ5678K2Y7

Description              SAC      Rate      Amount
---------------------------------------------------------
Web Application          998314   ₹80,000   ₹80,000
Development - Phase 2

                         Taxable Amount:       ₹80,000
                         IGST @ 18%:           ₹14,400
                         Total Amount:         ₹94,400

Amount in Words: Ninety-Four Thousand Four Hundred Rupees Only

Bank Details:
Account Name: Rajan Kumar
Account No: XXXXXXXXX
Bank: HDFC Bank, Pune
IFSC: HDFC0001234

Authorized Signature: _____________

Since Rajan is in Maharashtra and the client is in Karnataka (inter-state), the full 18% applies as IGST.

If Rajan's client were also in Maharashtra (intra-state), the line would change to:

• CGST @ 9%: ₹7,200
• SGST @ 9%: ₹7,200
• Total: ₹94,400 (same total, different split)

The Bill of Supply: For Unregistered Freelancers

If you're not GST-registered (income below ₹20 Lakhs), you issue a Bill of Supply — not a Tax Invoice. A Bill of Supply:

• Does NOT include GST
• Does NOT show a GSTIN (you don't have one)
• Still includes your name, address, client details, service description, and total amount
• Should be labeled "Bill of Supply" (not "Tax Invoice")

This is perfectly legal and accepted by clients for amounts where their ITC claim isn't possible anyway (since you can't issue GST-inclusive invoices without registration).

Common Mistakes to Avoid

Mistake 1: Applying CGST/SGST for inter-state clients If your client is in another state, always use IGST — not CGST/SGST. Applying the wrong tax type means your client files for ITC incorrectly, which creates problems during GST reconciliation.

Mistake 2: Not mentioning the SAC code This is legally required. Many freelancers skip it on informal invoices. If your invoice is for a large amount and goes through a company's accounts payable system, a missing SAC code can cause rejection.

Mistake 3: Sending invoices after 30 days For services, you should raise the invoice within 30 days of completion of service (or continuous supply). Late invoicing can cause compliance issues for both you and your client.

Mistake 4: Using non-sequential invoice numbers Each financial year's invoices should be numbered sequentially. If you accidentally skip a number or reissue, keep a record and explain it if asked during a GST audit.

Mistake 5: Not keeping copies Under GST law, you must retain copies of all tax invoices for at least 6 years. Store digital copies in a cloud folder with proper organization.

👉 Generate a professional GST-compliant invoice in seconds Our Free Invoice Generator creates clean, professional invoices with all mandatory GST fields. Download as PDF and send directly to your client.

Quick FAQs

1. Do I need to charge GST if I'm billing a foreign client?

If you provide services to a client outside India, this qualifies as "export of services" and is typically zero-rated under GST (0% GST, not 18%). You don't charge GST, but you should ideally have a Letter of Undertaking (LUT) filed with the GST department. We have a separate guide on invoicing foreign clients.

2. My client is an individual (not a business). Do I still charge GST?

Yes, if you're GST-registered, you charge GST on all taxable services regardless of whether the client is an individual or a business. For individuals, you don't need their GSTIN (they won't have one).

3. What if I made an error on an invoice I already sent?

You issue a Credit Note (if you overcharged) or Debit Note (if you undercharged). These are GST-compliant adjustment documents that you declare in your GST returns. Don't just modify and resend the original invoice.

4. Can I issue invoices in USD for foreign clients?

Yes. For export of services, invoices in foreign currency are acceptable. Convert the amount to INR at the RBI reference rate on the invoice date for your own accounting records.

5. My invoice amount is below ₹200 for a small task. Do all these rules still apply?

For very small B2C (business to consumer) transactions under ₹200, there are some relaxed rules around issuing individual invoices — consolidated daily invoices are allowed. However, for any B2B transaction (client with GSTIN), a proper tax invoice is required regardless of amount.

Disclaimer

GST rules and invoice requirements are governed by the CGST Act and related rules. This guide reflects current provisions but may not cover all edge cases. Consult a GST practitioner for specific compliance questions.