GST Invoice Format in Excel (Auto-Numbering + Tax)

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Last updated: 27 June 2026 · Fields aligned to CGST Rule 46 and GST 2.0 rates.

A GST invoice in Excel needs three working parts: a fixed header carrying your GSTIN and the buyer's details, an items table that computes tax per line, and a totals block — plus a unique, sequential serial number on every bill. Build the header once, use VLOOKUP to pull each item's HSN and rate from a master sheet, and an IF formula to apply CGST+SGST or IGST. Auto-number the serial so no two invoices ever clash.

Key takeaways

• A compliant invoice carries all Rule 46 fields: your name/GSTIN, a consecutive serial number, date, buyer details, HSN/SAC, taxable value, rate and amount of each tax, and place of supply.
• Auto-numbering is mandatory in spirit: the serial must be unique and sequential within the year — never repeat or skip arbitrarily.
• VLOOKUP the HSN master so description and rate fill automatically and stay consistent with GSTR-1.
• Let an IF decide CGST+SGST vs IGST from the buyer's state code.
• Round tax to two decimals with ROUND() so line totals add up cleanly.
• Templates are free to download, no sign-up.

Fact box. Under CGST Rule 46, a tax invoice must carry a consecutive serial number — unique for a financial year — not exceeding sixteen characters, using letters, numerals, special characters and combinations thereof. (Source: CGST Rules, Rule 46.)

What must a GST invoice in Excel contain?

Every tax invoice needs the particulars in Rule 46. At minimum:

1. Supplier's name, address and GSTIN.
2. A consecutive serial number (≤16 characters, unique for the financial year).
3. Date of issue.
4. Recipient's name, address and GSTIN (and place of supply with state code, for inter-state).
5. HSN/SAC code for each item.
6. Description, quantity, unit and taxable value.
7. Rate and amount of CGST, SGST/UTGST, IGST, and cess if any.
8. Whether tax is payable on reverse charge.
9. Signature or digital signature of the supplier.

How do I set up auto-numbering in Excel?

Make the serial build from a prefix, the financial year, and a running number so it is sequential and readable, e.g. INV/2026-27/0001.

• If A2 holds a plain counter (1, 2, 3…), display the serial with: ="INV/2026-27/"&TEXT(A2,"0000")
• For a single live invoice template, store the last-used number in a settings cell and add 1 when you start a new bill, then save a copy. This keeps numbers unique because Excel does not auto-increment a saved-over template by itself.

Tip: never reuse or back-date a serial. If you cancel an invoice, keep the number and mark it "cancelled" rather than deleting it, so the sequence has no gaps to explain.

How do I auto-fill HSN, description and rate?

Keep an HSN master sheet (code, description, GST rate) and look it up from each invoice line. With the item code in B8:

• Description: =VLOOKUP(B8, HSN!$A:$C, 2, FALSE)
• GST rate: =VLOOKUP(B8, HSN!$A:$C, 3, FALSE)

XLOOKUP works too and avoids column-counting: =XLOOKUP(B8, HSN!A:A, HSN!C:C). Full lookup patterns are in VLOOKUP HSN codes & rates.

How do I calculate the tax on each line?

Compute the taxable value, then split tax by place of supply. With quantity in C8, rate-per-unit in D8, GST rate in E8, and your state code in $B$2 vs buyer's in $B$4:

Wrap tax in ROUND(…, 2) so the rupee-paise totals reconcile. The reasoning behind the CGST/SGST/IGST split is in Calculate CGST/SGST/IGST in Excel.

Fact box. Tax amounts on an invoice should be rounded to two decimal places, and the final invoice value may be rounded to the nearest rupee under Section 170 of the CGST Act. Use ROUND() to keep line totals consistent. (Source: CGST Act, Section 170.)

How do I total the invoice?

Sum each tax column and the taxable values:

• Total taxable value: =SUM(F8:F20)
• Total CGST / SGST / IGST: =SUM(G8:G20) (and so on)
• Invoice total: =TaxableTotal + CGSTtotal + SGSTtotal + IGSTtotal
• Round-off to nearest rupee: =ROUND(InvoiceTotal, 0) - InvoiceTotal shown as a separate "round off" line.

How Ankeshan helps: Ankeshan numbers each invoice automatically, fills HSN and the current rate, and applies the right tax split — all inside Excel, with the data ready for your GSTR-1. It's launching soon; join the waitlist for the free invoice template.

Frequently asked questions

Is an Excel GST invoice valid? Yes, if it carries every field required by CGST Rule 46. The software does not affect validity — see Is an Excel GST invoice legally valid?.

How long can a GST invoice number be? Up to 16 characters, using letters, numerals and special characters, and it must be unique within the financial year.

Can I start invoice numbers from 1 each financial year? Yes. A common, compliant practice is to restart the running number each financial year, embedding the year in the serial (e.g. INV/2026-27/0001) to keep it unique.

Do I need a separate invoice format for inter-state sales? No. The same template works — your IF formula simply charges IGST instead of CGST+SGST based on the buyer's state code.

Should I show HSN on every invoice? Businesses up to ₹5 crore turnover must show at least 4-digit HSN on B2B invoices; above ₹5 crore, 6 digits on all invoices.

Sources

• CGST Rules, Rule 46 (tax invoice particulars); CGST Act, Section 170 (rounding).
• GSTN HSN reporting advisory (Table 12) — gst.gov.in.

General information, not professional advice. Verify on the official portal for your case. Reviewed by a Chartered Accountant; last updated 27 June 2026.

Related: GST in Excel — complete guide » · Calculate CGST/SGST/IGST in Excel » · VLOOKUP HSN codes & rates » · Is an Excel invoice legally valid? »