GST Invoice Requirements in India: Every Field

Every GST-registered business in India must issue a tax invoice for every taxable supply, and that invoice must contain 16 mandatory fields prescribed under Rule 46 of the CGST Rules. Missing any of these fields can lead to penalties, input tax credit rejection, and delays in payment. This article explains each required field, why it matters, and how to avoid common mistakes.

Formula

The calculator above computes the total GST and the grand total of an invoice. The formula is:

Total GST = (Invoice value × CGST rate / 100) + (Invoice value × SGST rate / 100)

Grand total = Invoice value + Total GST

Where:

• Invoice value – the taxable value of goods or services (₹)
• CGST rate – Central GST rate (%)
• SGST rate – State GST rate (%)
• Total GST – combined CGST + SGST amount (₹)
• Grand total – amount the buyer pays (₹)

For inter-state supplies, CGST and SGST are replaced by IGST (Integrated GST), and the total GST is simply the invoice value × IGST rate.

Worked Example

Using the default values from the calculator:

• Invoice value = ₹10,000
• CGST rate = 9%
• SGST rate = 9%

Step 1: Calculate CGST: 10,000 × 9 / 100 = ₹900

Step 2: Calculate SGST: 10,000 × 9 / 100 = ₹900

Step 3: Total GST = 900 + 900 = ₹1,800

Step 4: Grand total = 10,000 + 1,800 = ₹11,800

The calculator shows the same result: Total GST ₹1,800.00 and Grand total ₹11,800.00.

Background: Why the 16 Fields Exist

The GST law (CGST Act, 2017) requires a tax invoice to contain enough information to establish the supply, the parties, the tax liability, and the recipient’s eligibility for input tax credit. The 16 fields are listed in Rule 46 of the CGST Rules, 2017. They are not optional – even a single missing field can invalidate the invoice for tax purposes.

The fields were designed to create a uniform format across India, making it easier for the GST Network (GSTN) to match invoices with returns and for tax officers to audit. They also help the recipient claim input tax credit (ITC) – if the invoice lacks the recipient’s GSTIN or the HSN code, the ITC may be rejected.

The 16 Mandatory Fields on a GST Invoice

Here is the complete list of fields that must appear on every GST tax invoice (unless the invoice is for a B2C supply of up to ₹200, where a simplified invoice is allowed):

1. Name, address, and GSTIN of the supplier – the legal name as per the GST registration certificate.
2. Invoice number – a unique sequential number, usually with a prefix or year code.
3. Invoice date – the date of issue.
4. Name, address, and GSTIN of the recipient – if the recipient is registered; for unregistered recipients, the name and address are enough.
5. HSN code – the Harmonised System of Nomenclature code for the goods or services (mandatory for B2B and for B2C above certain turnover thresholds).
6. Description of goods or services – a clear, detailed description.
7. Quantity and unit – for goods; for services, the quantity may be “1� or a unit like “hour�.
8. Total value of supply – before tax.
9. Taxable value – the value on which GST is calculated (after discounts).
10. Rate of GST – the applicable rate (e.g., 5%, 12%, 18%, 28%).
11. Amount of CGST – the central tax component.
12. Amount of SGST or UTGST – the state/union territory tax component.
13. Amount of IGST – for inter-state supplies (instead of CGST+SGST).
14. Place of supply – the state/UT where the goods or services are delivered.
15. Signature or digital signature – of the supplier or an authorised representative.
16. QR code – for B2C invoices with taxable value above ₹50,000 (mandatory from December 2019).

For exports, additional fields like the shipping bill number and the export promotion copy are required.

How to Choose the Right Invoice Type

Not every supply uses the same invoice format. The main types are:

• Tax invoice – for normal taxable supplies (B2B and B2C).
• Bill of supply – for exempt supplies or when the supplier is under the composition scheme.
• Credit note / debit note – to correct invoices or adjust values.
• Receipt voucher – when you receive advance payment.
• Refund voucher – when you refund an advance.
• Delivery challan – for goods sent for job work, on approval, or for transportation without a sale.

Choose the type based on the nature of the supply. Using the wrong document can lead to ITC denial or penalties.

Common Mistakes and How to Avoid Them

Here are the most frequent errors businesses make on GST invoices:

• Missing GSTIN of the recipient – always verify the recipient’s GSTIN on the GST portal before issuing.
• Wrong HSN code – use the correct 8-digit code; wrong codes can misclassify the tax rate.
• Incorrect tax rates – check the rate for your product/service; some items have special rates (e.g., 0.25% for rough diamonds).
• Not mentioning the place of supply – this determines whether CGST+SGST or IGST applies.
• Using a single invoice for multiple supplies with different rates – you must show the breakup of each rate separately.
• Forgetting the signature – a digital signature or handwritten signature is mandatory.

A simple way to avoid mistakes is to use accounting software that auto-fills most fields from your GST registration data.

Costs and Penalties for Non-Compliance

There is no direct fee for issuing an invoice, but non-compliance can be costly. If an invoice lacks mandatory fields, the recipient may not be able to claim input tax credit, leading to a higher effective cost. The supplier may face a penalty under Section 122 of the CGST Act – up to ₹25,000 for each invoice. Additionally, if the invoice is not issued at all, the penalty can be ₹10,000 or the amount of tax evaded, whichever is higher.

For late filing of GST returns that include invoice details, interest at 18% per annum applies. These costs can quickly add up, so it is worth investing in a reliable billing system.

Frequently Asked Questions

Is a GST invoice required for every sale?

Yes, every registered person must issue a tax invoice for every taxable supply. For B2C sales under ₹200, a simplified invoice with fewer fields is allowed, but it must still contain the supplier’s name, GSTIN, invoice number, date, description, and total amount.

What happens if I miss the HSN code?

Missing the HSN code can lead to the invoice being considered invalid, and the recipient may be denied input tax credit. The HSN code is mandatory for B2B invoices and for B2C invoices if your turnover exceeds ₹5 crore (or ₹1 crore for certain businesses).

Can I issue a consolidated invoice for multiple deliveries?

Yes, you can issue a consolidated invoice at the end of the month for multiple supplies made to the same recipient, provided you issue a delivery challan for each dispatch. The consolidated invoice must contain all the mandatory fields and a reference to the delivery challans.

Do I need to show CGST and SGST separately?

Yes, for intra-state supplies, you must show the CGST and SGST amounts separately. For inter-state supplies, you show only the IGST amount. This is because CGST and SGST are paid to different authorities.

What is a bill of supply and when is it used?

A bill of supply is issued instead of a tax invoice when the supply is exempt from GST or when the supplier is under the composition scheme. It does not show any tax amount, but it must contain the name, address, GSTIN, invoice number, date, description, and value.

Can I correct a mistake on an already-issued invoice?

Yes, you can issue a credit note or debit note to correct the value or tax amount. The credit note must be issued within the same financial year or before September of the following year. It must contain the original invoice number and date.

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in t | Invoice value (₹) | ₹ | 10000 | 0
in r | GST rate (%) | % | 18 | 0 | 100
in cgst | CGST rate (%) | % | 9 | 0 | 100
in sgst | SGST rate (%) | % | 9 | 0 | 100
out total | Total GST amount | ₹ | (t * cgst / 100) + (t * sgst / 100) | 2
out grand | Invoice total with GST | ₹ | t + (t * cgst / 100) + (t * sgst / 100) | 2