Running a business in India means issuing clean, accurate GST tax invoices that your clients can use to claim Input Tax Credit (ITC). Hand-written paper bills or makeshift Excel spreadsheets often contain calculation errors, missing HSN codes, or invalid tax splits that delay payments and trigger audit notices.
Fortunately, modern online invoice generators allow you to create professional, GST-compliant PDF bills in less than 2 minutes directly from your browser—without paying for complex ERP or accounting software.
In this guide, we cover the exact mandatory fields required by the GST Council, how tax rates are applied, and how you can generate your bills for free today.
To create a GST invoice online for free, enter your business GSTIN and buyer details, add line items with 4 to 8 digit HSN/SAC codes, and select whether the transaction is Intra-state (CGST + SGST split 50/50) or Inter-state (IGST). A valid GST invoice must include an invoice number, invoice date, place of supply, taxable value, and tax rate breakdown before downloading or sharing as a PDF.
Indian business owners, consultants, and contractors seeking a fast, zero-cost, compliant tool to issue professional GST bills without subscribing to bulky accounting software.
Mandatory Fields on a Legal GST Tax Invoice in India
Under Section 31 of the CGST Act, 2017 read with Rule 46 of the CGST Rules, a tax invoice issued by a registered taxpayer must contain specific statutory details to be legally recognized.
If any of these key details are missing, your buyer cannot claim Input Tax Credit (ITC) on GSTR-2B, which can strain client relationships and delay payment release.
- Name, address, and GSTIN of the supplier (your business)
- A consecutive serial number (invoice number) unique for each financial year
- Date of issue of the invoice
- Name, address, and GSTIN or UIN of the recipient (if registered)
- Place of supply along with the name of the destination State (critical for determining CGST/SGST vs IGST)
- Harmonised System of Nomenclature (HSN) code for goods or Service Accounting Code (SAC) for services
- Description of goods or services, quantity, unit, and total taxable value
- Applicable GST rate (0%, 5%, 12%, 18%, or 28%) and exact breakdown of CGST, SGST, or IGST
- Total invoice amount in words and figures, including bank payment details or UPI QR code for fast payment
Understanding Intra-State vs Inter-State Tax Calculations
One of the most frequent invoicing errors is applying the wrong tax component. Under GST, tax liability is determined by your business location (place of supplier) compared to the customer's Place of Supply (POS).
When both are within the same State or Union Territory (Intra-state), you must split the GST equally into Central Tax (CGST) and State Tax (SGST). When selling across state borders (Inter-state), you must apply Integrated Tax (IGST) at the full rate.
If you are unsure of the exact rate split, you can use our free GST Calculator to verify numbers before generating your bill.
- Intra-State Example: A seller in Maharashtra billing a buyer in Mumbai for ₹10,000 at 18% GST applies 9% CGST (₹900) + 9% SGST (₹900) = Total ₹11,800.
- Inter-State Example: A seller in Maharashtra billing a buyer in Delhi for ₹10,000 at 18% GST applies 18% IGST (₹1,800) = Total ₹11,800.
- Export / SEZ Supply: Treated as inter-state supply (IGST), with options for LUT (Letter of Undertaking) without payment of integrated tax.
HSN and SAC Code Requirements for Small Businesses
The CBIC mandates HSN (Harmonised System of Nomenclature) reporting based on your Aggregate Annual Turnover (AATO):
Businesses with AATO up to ₹5 Crores must report at least a 4-digit HSN/SAC code for B2B tax invoices (reporting for B2C invoices is optional but recommended). Businesses with AATO over ₹5 Crores must report a 6-digit HSN/SAC code on all B2B and B2C tax invoices.
- Turnover up to ₹5 Cr: 4 digits HSN/SAC code mandatory for B2B supplies
- Turnover above ₹5 Cr: 6 digits HSN/SAC code mandatory on all supplies
- Export & Import: 8 digits mandatory for all cross-border transactions
Step-by-step guide
Enter Your Business Details & GSTIN
Open the Digiting Card Free Invoice Generator. Input your legal company name, office address, phone, email, and 15-digit GSTIN. Upload your brand logo to create an instantly recognizable header.
Add Client Details & Place of Supply
Fill in the recipient's name, billing address, and GSTIN (for B2B clients). Select the correct Place of Supply state to automatically configure CGST/SGST or IGST tax routing.
Add Line Items with HSN/SAC Codes
List the products or services provided, their 4 or 6-digit HSN/SAC code, quantity, unit rate, and applicable GST slab (0%, 5%, 12%, 18%, or 28%). The generator automatically calculates subtotal, tax amount, and grand total.
Specify Payment Terms & Bank / UPI Details
Add your bank account number, IFSC code, and UPI ID or QR code so clients can settle your bill in 1 tap directly from their mobile banking or UPI apps.
Download PDF or Share Directly on WhatsApp
Click 'Download PDF' to save your print-ready invoice or share it straight to your client's WhatsApp chat with a single click.
Mistakes to avoid
Problem: Charging CGST + SGST when the client's place of supply is in another state results in an invalid tax credit and requires credit notes to rectify.
Fix: Always check the Place of Supply (POS) state before finalizing the invoice; use IGST whenever the supplier state differs from the client state.
Problem: Invoices without statutory 4 or 6-digit HSN codes can attract penalties under Section 125 of the CGST Act and cause client GSTR-2B mismatches.
Fix: Verify your products' 4-digit HSN or service SAC code once and save it in your recurring item catalog.
Problem: GST laws require unique, sequential invoice numbering within each financial year (e.g., INV/26-27/001). Gaps or duplicate numbers raise red flags during tax scrutiny.
Fix: Maintain a standard numbering scheme like INV-2026-001 and never reuse deleted invoice numbers.
Frequently asked questions
What is the difference between a Tax Invoice and a Bill of Supply under GST?
A Tax Invoice is issued by normal registered taxpayers charging GST on taxable goods and services. A Bill of Supply is issued by taxpayers enrolled under the GST Composition Scheme or those dealing exclusively in exempt goods/services where no tax is charged.
Can I issue an invoice if my annual turnover is below ₹20 Lakhs and I don't have a GSTIN?
Yes! Small businesses and freelancers below the mandatory GST threshold can issue standard commercial invoices or bills without GSTIN. Digiting Card's Invoice Generator allows you to toggle GST off with one click to issue clean non-GST invoices.
Is e-invoicing mandatory for small businesses?
As of 2026, mandatory e-invoicing (IRN generation via IRP portal) applies to B2B supplies by businesses with an aggregate annual turnover exceeding ₹5 Crores. Micro and small businesses below ₹5 Cr turnover are currently exempt from e-invoicing requirements.
How long should a business keep copies of GST tax invoices?
Under Section 36 of the CGST Act, every registered taxable person must maintain invoice records, accounts, and books for at least 72 months (6 years) from the due date of furnishing the relevant annual return.
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