Is an estimate bill legal under GST?

Yes, as a quotation or working document. It carries no tax and records no sale. What GST law requires is that every actual taxable sale is documented by a tax invoice (or bill of supply for composition dealers) that appears in your returns.

Can my buyer claim input tax credit from an estimate?

No. Input tax credit needs a valid tax invoice with your GSTIN, the buyer's GSTIN, HSN codes and the tax shown separately, filed in your GSTR-1 so it reaches their GSTR-2B.

Can one business have two GST invoice series?

Each GST registration runs its own consecutive invoice series. A business holding two GSTINs therefore runs two series, one per registration, and files a separate GSTR-1 for each. Software that models each registration as its own book keeps the series from tangling.

Does a GST tax invoice replace the delivery challan?

No, they travel together for different readers. The challan accompanies the goods, often with prices hidden, for the lorry and the receiving godown. The tax invoice documents the sale for the buyer's accounts and your returns.

What is a bill of supply and when do I use it?

A bill of supply is the document composition dealers and sellers of exempt goods issue instead of a tax invoice. It shows no tax, and for composition dealers it must carry the declaration that the seller is not eligible to collect tax.

Estimate bill and tax invoice: two documents, two jobs

GST & Accounts · 15 August 2026

Walk into any Sivakasi wholesale office and you will find two kinds of paper. The estimate: fast, flexible, quoted in the trade's own MRP-and-discount language, used to negotiate, pack and reconcile. And the tax invoice: the formal document under GST Rule 46, with GSTINs, HSN codes, a consecutive serial number and the tax shown line by line.

Both documents are legitimate, and each has a job the other does badly. Trouble starts only when a business is unclear about which job is which. This guide draws the line, and shows how to run both documents from one system without the line blurring.

What the estimate bill is for

An estimate (a quotation, a proforma, the kachha slip of trade slang) is a working document. It carries no tax liability by itself because it does not record a sale; it records an intention. That is what makes it useful:

Negotiation. Rates move during a season. An estimate can be revised five times without touching any statutory series.
Packing and dispatch. The godown packs against the estimate's case and piece quantities; a price-hidden challan travels with the lorry.
Counter speed. A retail counter billing a queue needs a document that saves in seconds, not one that demands a GSTIN and place of supply first.

What only the tax invoice can do

The moment a taxable sale happens, GST law wants a tax invoice (or, for composition dealers, a bill of supply). Rule 46 fixes what it must contain: the seller's GSTIN, a serial number unique for the year, the buyer's GSTIN for B2B, HSN codes, taxable value, the CGST/SGST or IGST split, and a signature. This is the document that:

carries your buyer's input tax credit: without it they cannot claim back the 18%,
feeds your GSTR-1, and must match what your buyer sees in their GSTR-2B,
supports the e-way bill when the consignment crosses the threshold,
stands as evidence of the sale for assessments, audits and disputes.

The line to hold: every taxable sale needs its tax invoice, and the tax invoices you issue must reconcile with what you file. An estimate is a stage on the way to a sale, never a substitute for the invoice that records it.

Why one GST registration is often not the whole story

Family businesses in the trade commonly hold more than one GST registration: the main shop and a sister agency, a partnership and a proprietorship, or separate firms for wholesale and retail lines. Each registration is its own taxpayer, with its own invoice series, its own GSTR-1 and its own signature on the paper.

Run from one bill book, this goes wrong in predictable ways: numbers issued out of series, an invoice raised under the wrong firm, one firm's sales filed in the other's return. Run from two separate apps, the product list and customer list split in half and neither is complete.

Two documents, one system

This is how Crackers Billing Software structures it. Estimate bills run the counter: they move stock, feed the party ledger and print in the trade's format. Beside them sits a separate GST invoice book for the statutory paperwork.

Each GST registration you hold becomes an issuer with its own series (SA/GST/0004 style), its own e-sign and its own prefix, so numbering stays consecutive per registration, as Rule 46 requires.
All issuers share one GST product list, pre-seeded with 300+ crackers items under HSN 3604 at 18%, and one transporter list with carrier GSTINs and vehicles.
The buyer's GSTIN is verified in one click against the GST network before the invoice is saved, and place of supply drives the CGST/SGST or IGST split automatically.
The print settings are per book: number of copies, your declaration, terms, HSN-wise summary and bank details, so the paper leaving each firm looks the way that firm's paper should.

Because the two documents live in one system but separate books, the estimate stays as fast as the counter needs, and the tax invoice stays as exact as the law needs. Nothing is double-entered, and nothing statutory depends on memory.

The season-end payoff

In November, the accountant asks the same two questions every year: which sales are invoiced, and do the invoices match the filings. A business that kept its tax-invoice book clean answers with an export per registration. One that billed everything as estimates and meant to regularise later spends the quietest month of its year reconstructing paperwork. This article is general information for the trade, not tax advice; confirm your own case with a GST practitioner.

Frequently asked questions

Is an estimate bill legal under GST?: Yes, as a quotation or working document. It carries no tax and records no sale. What GST law requires is that every actual taxable sale is documented by a tax invoice (or bill of supply for composition dealers) that appears in your returns.
Can my buyer claim input tax credit from an estimate?: No. Input tax credit needs a valid tax invoice with your GSTIN, the buyer's GSTIN, HSN codes and the tax shown separately, filed in your GSTR-1 so it reaches their GSTR-2B.
Can one business have two GST invoice series?: Each GST registration runs its own consecutive invoice series. A business holding two GSTINs therefore runs two series, one per registration, and files a separate GSTR-1 for each. Software that models each registration as its own book keeps the series from tangling.
Does a GST tax invoice replace the delivery challan?: No, they travel together for different readers. The challan accompanies the goods, often with prices hidden, for the lorry and the receiving godown. The tax invoice documents the sale for the buyer's accounts and your returns.
What is a bill of supply and when do I use it?: A bill of supply is the document composition dealers and sellers of exempt goods issue instead of a tax invoice. It shows no tax, and for composition dealers it must carry the declaration that the seller is not eligible to collect tax.

Sources

This guide is general information for the crackers trade, not legal, tax or safety advice. Rules change by state and by year; confirm the current position with your licensing authority or accountant.