Free Invoice Generator for Indian Businesses
Every GST-registered business in India must issue tax invoices that meet specific legal requirements. A non-compliant invoice can lead to rejection of Input Tax Credit claims, penalties during audits, and disputes with buyers. This guide explains exactly what a GST invoice must contain, the different types of invoices, numbering rules, and how to create compliant invoices for free using DoAide's Invoice Generator.
Why You Need a Professional Invoice Generator
Invoicing is not just about requesting payment — under GST, invoices are legal documents that form the basis of tax liability and Input Tax Credit claims throughout the supply chain. Getting your invoices right is critical for three reasons:
GST Compliance
Under Sections 31 and 33 of the CGST Act, every registered person making a taxable supply must issue a tax invoice. The invoice must contain specific fields prescribed under Rule 46 of the CGST Rules. Missing any mandatory field can make the invoice non-compliant, which means the recipient cannot claim ITC on that purchase.
Cash Flow Management
Professional invoices with clear payment terms, due dates, and bank details get paid faster. Studies show that businesses using professional invoicing tools receive payment 15–20 days faster on average compared to those using manual or unstructured invoices. Clear line items and GST breakdowns also reduce disputes and back-and-forth with buyers.
Legal Validity
In case of legal disputes or recovery proceedings, a properly formatted invoice serves as primary evidence of the transaction. Courts and arbitration panels rely heavily on invoice documentation. An invoice that meets all GST requirements is far stronger legally than an informal receipt or handwritten bill.
Mandatory Fields in a GST Invoice
Rule 46 of the CGST Rules prescribes the following mandatory fields for a GST tax invoice. Every field listed below must be present for the invoice to be legally compliant:
| Field | Details | Importance |
|---|---|---|
| Supplier Name | Legal name as registered under GST | Must match GSTIN records exactly |
| Supplier Address | Principal place of business | Determines place of supply for tax calculation |
| Supplier GSTIN | 15-digit GST Identification Number | Recipient uses this to verify the supplier |
| Invoice Number | Unique, sequential, max 16 characters | No gaps allowed; resets each financial year |
| Date of Issue | Date the invoice is issued | Determines the tax period for return filing |
| Recipient Name | Name of the buyer/recipient | Required for all B2B invoices |
| Recipient GSTIN | Buyer's GSTIN (if registered) | Required for B2B; "URP" for unregistered persons |
| HSN / SAC Code | Product classification code | 4 or 6 digits based on turnover |
| Description | Description of goods or services supplied | Must clearly identify what was supplied |
| Quantity & Unit | Quantity and unit of measurement (for goods) | Required for goods; optional for services |
| Taxable Value | Value of supply before GST | Base amount on which GST is calculated |
| GST Rate & Amount | CGST + SGST (intra-state) or IGST (inter-state) | Must be shown separately for each line item |
| Place of Supply | State where supply is delivered | Determines whether CGST+SGST or IGST applies |
| Total Invoice Value | Taxable value + GST amount | Total payable amount |
| Signature | Physical or digital signature of supplier | Authenticates the invoice |
Use DoAide's free Invoice Generator to automatically include all mandatory fields. Just enter your business details and line items — the tool handles GST calculations, HSN codes, and formatting.
Types of GST Invoices
GST law recognizes several types of invoices, each used for a specific purpose. Using the correct type is essential for compliance:
| Invoice Type | When Used | Key Difference |
|---|---|---|
| Tax Invoice | Regular taxable supplies of goods or services | Shows GST separately; recipient can claim ITC |
| Bill of Supply | Exempt supplies or by Composition Scheme dealers | No GST shown; no ITC available to recipient |
| Credit Note | When invoice value or GST charged needs to be reduced (returns, discounts) | Reduces the supplier's output tax liability |
| Debit Note | When invoice value or GST charged needs to be increased | Increases the supplier's output tax liability |
| Receipt Voucher | When advance payment is received before supply | GST is payable on the advance amount |
| Refund Voucher | When advance is refunded because supply did not happen | Reverses the GST paid on the advance |
| Delivery Challan | Goods sent for job work, exhibition, or on approval | Not a tax document; no GST charged |
GST Invoice Numbering Rules
GST invoice numbers must follow specific rules under Rule 46 of the CGST Rules:
- Sequential and consecutive: Invoice numbers must be in a consecutive serial order with no gaps. Jumping from INV-001 to INV-005 without issuing 002, 003, and 004 is non-compliant.
- Unique per financial year: Each invoice number must be unique within the financial year. You can restart the sequence from 1 at the beginning of each financial year (April 1).
- Maximum 16 characters: The total length of the invoice number cannot exceed 16 characters, including any prefixes, numbers, and special characters.
- Alphanumeric with special characters: You can use alphabets (A–Z), numerals (0–9), and special characters like dash (-) and forward slash (/). Common formats include INV/2026-27/001 or MUM-2627-0001.
- Multiple series allowed: Businesses with multiple branches or locations can maintain separate invoice series with unique prefixes (e.g., DEL-001, MUM-001, BLR-001).
Do not use the same invoice number series for tax invoices and credit notes. Credit notes and debit notes must have their own separate sequential numbering series. Mixing them creates reconciliation issues during return filing.
Intra-State vs Inter-State Invoicing
The place of supply determines whether you charge CGST + SGST (intra-state) or IGST (inter-state). Getting this wrong is one of the most common invoicing errors:
| Scenario | Tax Charged | Example (18% GST) |
|---|---|---|
| Intra-state (supplier and recipient in same state) | CGST (9%) + SGST (9%) | Rs 1,000 + Rs 90 CGST + Rs 90 SGST = Rs 1,180 |
| Inter-state (supplier and recipient in different states) | IGST (18%) | Rs 1,000 + Rs 180 IGST = Rs 1,180 |
| Export (supply outside India) | IGST (18%) or 0% with LUT | Zero-rated supply; can claim refund |
The total amount remains the same, but the tax must be split correctly. An intra-state invoice showing IGST instead of CGST+SGST will be flagged during GSTR-1 filing. Use DoAide's GST Calculator to verify the correct tax split before invoicing.
How to Create Free Invoices with DoAide
DoAide's Invoice Generator is a free tool designed specifically for Indian businesses. Here is how to create a GST-compliant invoice in under two minutes:
- Visit invoice.doaide.com — no registration or sign-up required to get started
- Enter your business details — company name, address, GSTIN, and contact information. These are saved for future invoices.
- Add buyer details — recipient name, address, and GSTIN. The tool automatically determines intra-state vs inter-state based on GSTINs.
- Add line items — enter product/service description, HSN/SAC code (use the HSN Search tool to find the right code), quantity, rate, and GST percentage.
- Review the calculated totals — the tool automatically calculates taxable value, CGST, SGST, or IGST amounts, and the total invoice value.
- Generate and download — click Generate to create a professional PDF invoice ready to share with your client via email or WhatsApp.
DoAide's Invoice Generator includes: automatic GST calculation with correct CGST/SGST/IGST split, HSN/SAC code lookup, professional PDF templates, amount in words, bank details section, and terms & conditions. All invoices are generated locally — your data stays on your device.
Common Invoice Mistakes to Avoid
These are the most frequent invoicing errors that lead to compliance issues, ITC rejections, and audit problems:
- Wrong GSTIN: Always verify the buyer's GSTIN before issuing the invoice. A single wrong digit means the invoice will not match during GSTR-2B reconciliation.
- Missing or incorrect HSN code: Using the wrong HSN code can result in the wrong GST rate being applied. This triggers demand notices during audits.
- IGST on intra-state supply: Charging IGST when both supplier and buyer are in the same state is incorrect. The system will flag this as a mismatch.
- Non-sequential invoice numbers: Gaps in invoice numbering suggest suppressed invoices and will attract scrutiny during audits.
- Missing place of supply: Omitting the place of supply makes it impossible to verify whether the correct tax (CGST+SGST vs IGST) was charged.
- Invoicing after the due date: Tax invoices for goods must be issued at or before the time of delivery. For services, the invoice must be issued within 30 days of supply completion.
- Not showing GST separately: The CGST and SGST (or IGST) amounts must be shown separately on each line item. Lumping them together is non-compliant.
Under Section 122 of the CGST Act, issuing an incorrect invoice attracts a penalty of Rs 10,000 or the tax amount involved, whichever is higher. For repeated or deliberate violations, the penalty can extend to Rs 25,000. Using a compliant invoice generator eliminates most of these errors automatically.
Create Your First Invoice Free
Generate professional, GST-compliant invoices in under two minutes. No sign-up required. All mandatory fields included automatically.
Create Invoice Free →Frequently Asked Questions
A GST tax invoice must contain: supplier's name, address, and GSTIN; a unique sequential invoice number; date of issue; recipient's name, address, and GSTIN (if registered); HSN/SAC code for each item; description, quantity, and unit; taxable value; GST rate and amount (CGST+SGST or IGST); place of supply; total invoice value; and signature.
A Tax Invoice is for regular taxable supplies and shows GST separately, allowing the recipient to claim ITC. A Bill of Supply is for exempt supplies or composition scheme dealers — it does not show GST, and the recipient cannot claim ITC on it.
GST law does not prescribe a specific template or design. However, all mandatory fields must be present. As long as every required field is included, any format works — handwritten, printed, or digital. Tools like DoAide's Invoice Generator ensure compliance automatically.
Yes. Free invoice generators like DoAide are fully compliant with GST requirements. They automatically include all mandatory fields, calculate GST amounts correctly, and generate professional PDF invoices that are legally valid for GST filing and ITC claims.
Invoice numbers must be sequential (no gaps), unique per financial year, and no longer than 16 characters. They can contain alphabets, numerals, and special characters like dash and slash. A new sequence can start each financial year. Multiple series are allowed for businesses with multiple branches.