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Compliance Guide FY 2025–26
Last reviewed: 8 May 2026

GST Invoice Format

Understanding the mandatory fields in a GST invoice is critical to ensure buyers get ITC and you avoid penalties. Use this guide to learn the correct invoice structure and create printable draft summaries.

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⚠️ Safety & Compliance Notice:This page is for educational purposes. TheGSTCalculator.in is not a government website. The "invoice helper" creates printable draft summaries and quotations, not official tax invoices. Always verify GSTIN, HSN, and latest CBIC rules before issuing final invoices.

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Mandatory fieldsSample GST invoiceGoods vs ServicesCGST/SGST vs IGSTHSN/SAC requirementTax invoice vs Bill of supplyFinal issue checklistWhen to issue invoiceE-invoice warningFAQs

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What is a GST invoice format?

A GST invoice (or tax invoice) is a document issued by a registered supplier to a recipient, detailing the goods or services supplied and the tax charged. While the GST law doesn't mandate a specific "visual layout," it requires about 16-20 mandatory fieldsto make the document legally valid for claiming Input Tax Credit (ITC).

Mandatory fields checklist

Supplier Details
Name, address, and GSTIN of the supplier.
Invoice Number
A consecutive serial number (up to 16 chars) unique for a FY.
Date of Issue
The date on which the invoice is generated.
Recipient Details
Name, address, and GSTIN (for B2B) of the buyer.
HSN/SAC Code
Classification code for goods (HSN) or services (SAC).
Description
A clear description of the goods or services supplied.
Quantity & Unit
Measurement unit (e.g., Kg, Pcs) and quantity.
Taxable Value
The price before adding GST.
GST Rate
The applicable tax slab (0%, 5%, 12%, 18%, 28%).
Tax Amount
CGST/SGST (Intra-state) or IGST (Inter-state) values.
Place of Supply
State where the supply is consumed.
Signature
Physical or digital signature of the authorized person.

Sample GST invoice format reference

DescriptionHSN/SACQtyTaxable ValRateCGSTSGSTIGSTTotal
Electronic Parts (Intra-state)
Goods - MH to MH
8471xx10 Pcs₹10,00018%₹900₹900N/A₹11,800
Software Consultancy (Intra-state)
Service - KA to KA
9983xx1 Unit₹5,00018%₹450₹450N/A₹5,900
Industrial Tools (Inter-state)
Goods - MH to KA
8205xx2 Pcs₹2,00012%N/AN/A₹240₹2,240
💡 Quick Rule: Use CGST + SGST for same-state supplies and IGST for inter-state supplies. Always verify the Place of Supply before final issue to ensure correct tax application.

GST invoice for goods vs services

Goods Invoice

  • HSN Code: Mandatory classification.
  • Quantity/Unit: Kg, Pcs, Metres, etc.
  • Movement: E-way bill may apply depending on value.
  • Copies: 3 copies (Recipient, Transporter, Supplier).

Services Invoice

  • SAC Code: Services Accounting Code.
  • Description: Include billing period/project details.
  • POS: Highly critical for service tax splits.
  • Copies: 2 copies (Recipient, Supplier).

CGST/SGST vs IGST split

Intra-State (Same State)

Supplier in MH → Buyer in MH

  • Taxable Value: ₹1,000
  • CGST (9%): ₹90
  • SGST (9%): ₹90
  • Total Payable: ₹1,180
Inter-State (Different State)

Supplier in MH → Buyer in KA

  • Taxable Value: ₹1,000
  • IGST (18%): ₹180
  • Total Payable: ₹1,180

HSN/SAC requirement

Classification of goods and services is done via HSN (Harmonized System of Nomenclature) and SAC (Services Accounting Code). Accurate classification ensures the correct tax rate is applied and prevents ITC reconciliation issues.

4-digit HSN:Required for B2B supplies if aggregate turnover in prev FY was ≤ ₹5 Cr.
6-digit HSN:Mandatory for all B2B supplies if turnover > ₹5 Cr.
HSN/SAC Code Finder

Tax Invoice vs Bill of supply

Tax Invoice

Issued by regular taxpayers for taxable supplies. Includes GST rate and amount details. Enables Input Tax Credit (ITC).

Standard B2B / B2C

Bill of Supply

Issued by composition dealers or for exempt goods. No tax charged to customer. No ITC for the buyer.

No Tax Collected

Before issuing a final GST invoice

Verify Buyer GSTIN

Essential for B2B to ensure buyer gets ITC credit without mismatches.

Confirm HSN/SAC

Classification affects the applicable tax rate and reporting.

Check Place of Supply

Determines if you charge CGST+SGST or IGST.

Supplier Name, Address & GSTIN
Sequential Invoice Number series
Current Invoice Date
Correct Taxable Value
Correct GST Slab %
Tax Split (CGST/SGST/IGST)
Reverse Charge applicability
E-invoice / E-way bill check
Total Invoice Value (rounded)

Need to prepare a draft for verification?

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When should a GST invoice be issued?

Supply of Goods

Generally, the invoice should be issued before or at the time of removal of goods for supply to the recipient. Timing can vary for continuous supply or sales on approval.

Supply of Services

Generally, many service invoices are issued within 30 days from the date of supply of service, with separate timelines for certain sectors such as banking/insurance. Specific rules can apply for continuous supply and other cases.

Note: These are general practical reminders. Compliance timing can be nuanced and subject to official notifications. Always verify the latest rules on the GST portal or with your consultant.

E-invoice & IRN warning

If your aggregate turnover exceeds the mandatory threshold (currently ₹5 Cr in any previous FY), generating a manual PDF invoice is insufficient. You must generate a unique Invoice Reference Number (IRN) and a Signed QR Codevia the official government IRP portal.

Important Note:This website provides a draft invoice summary helper. It does NOT generate IRN or e-invoices. Always verify your e-invoicing status on the official portal.

Check E-invoice turnover thresholds

Frequently asked questions

Is there a fixed size or layout for a GST invoice?

No. The GST law specifies mandatory fields (like GSTIN, HSN, etc.) but does not mandate a specific layout or font size. Most businesses use A4 or A5 formats for clarity.

Can I create a GST invoice without a buyer GSTIN?

Yes, for B2C (Business to Consumer) supplies, the buyer GSTIN is not required. However, for B2B supplies, the buyer GSTIN is mandatory for them to claim Input Tax Credit (ITC).

Is HSN/SAC mandatory on every GST invoice?

Generally, yes. Businesses with turnover > ₹5 Cr require 6-digit HSN. Those below ₹5 Cr require 4-digit HSN for B2B supplies. Some small B2C retailers may have specific relaxations—verify current thresholds.

What happens if a wrong GSTIN is entered on the invoice?

If a wrong GSTIN is used, the transaction will not reflect in the correct buyer's GSTR-2B, preventing them from claiming ITC. You may need to issue a credit note and a fresh invoice or amend the return in subsequent periods.

Do I need different formats for goods and services?

The core mandatory fields remain the same, but a goods invoice requires HSN and Quantity/Unit, while a services invoice uses SAC and a description of the service (quantity may be optional or "1 service").

Is a proforma invoice the same as a GST tax invoice?

No. A proforma invoice is a preliminary document or quotation used before the actual supply. It is not a valid tax document for claiming ITC. A "Tax Invoice" must be issued as per GST rules.

What is the mandatory HSN code digit requirement?

As of 2024-25, businesses with turnover > ₹5 Cr generally need 6 digits of HSN. Those with turnover < ₹5 Cr need 4 digits for B2B supplies. Verify current thresholds on the GST portal.

Can I use a handwritten GST invoice?

Yes, provided all mandatory fields are present and the invoice series is sequential. However, digital invoices are preferred for easier return filing and compliance.

What is a Bill of Supply?

A Bill of Supply is issued by Composition Dealers or for exempt goods/services where tax cannot be charged. It does not show GST rates or amounts.

How many copies of a GST invoice are required?

For goods: 3 copies (Original for recipient, Duplicate for transporter, Triplicate for supplier). For services: 2 copies (Original for recipient, Duplicate for supplier).

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Sources & Methodology

Content is based on Section 31 of the CGST Act and Rule 46 of the CGST Rules regarding tax invoice requirements. Latest thresholds and compliance rules are tracked viaGST Portaland CBIC notifications.

Review our Accuracy Policyand Disclaimerbefore using this format for business decisions.

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