How to generate GST-compliant RA bills in Indian construction

Running-account (RA) bills are the default billing instrument in Indian construction contracts. A contractor doesn't wait until the building is complete to raise a ₹5 crore invoice; they issue progressive bills every month, each representing the work done since the last one. Every bill is a snapshot — cumulative from contract start, less what's already been billed.

In this post we'll walk through the fields, the GST treatment, and the TDS implications, using a concrete example.

The anatomy of an RA bill

An RA bill carries five amounts that must always reconcile:

1. Contract value — the agreed total for the scope.
2. Cumulative amount — total work-done value up to this bill, inclusive of this bill's portion.
3. Previous cumulative amount — what was on the prior RA bill.
4. This bill's amount — cumulative − previous cumulative.
5. Net payable — this bill minus advance recovery minus retention minus TDS, plus GST.

In Blueprint, cumulativeAmount and previousCumulativeAmount are stored on the invoice itself — there is no parallel spreadsheet you can forget to update.

GST: CGST + SGST vs IGST

Whether GST splits into CGST + SGST (intrastate) or collapses into a single IGST (interstate) depends on the place of supply. In construction, that's the project site. The rule of thumb:

• Contractor's principal place of business + site = same state → CGST + SGST.
• Contractor's principal place of business + site = different states → IGST.

Blueprint auto-detects this from the supplier and buyer state codes on each invoice. See CGST vs SGST vs IGST for contractors for the full worked example.

TDS Section 194C

Once the invoice is raised, the payer deducts TDS at source under Section 194C:

• 1% if the payee is an individual or HUF.
• 2% if the payee is any other person (including companies, LLPs).

TDS is computed on the pre-GST amount. Blueprint's billing module handles this automatically — the net payable shown on each invoice already reflects the deduction.

For a full discussion, see TDS 194C explained.

A worked example

Consider a ₹50 lakh BOQ-linked contract between a contractor based in Karnataka and a developer whose site is also in Karnataka:

Field	Value
Contract value	₹50,00,000
Work-done cumulative (this bill)	₹15,00,000
Previous cumulative	₹8,00,000
This bill's amount	₹7,00,000
GST @ 18% (CGST 9% + SGST 9%)	₹1,26,000
TDS 194C @ 2% (company payee)	₹14,000
Advance recovery	₹50,000
Retention @ 5%	₹35,000
Net payable	₹7,27,000

Blueprint's GST billing module captures all of this on one invoice, with the status history recorded for audit.

Financial year numbering

One last thing: invoice numbers must sequence within the Indian financial year (April–March), not the calendar year. Blueprint handles this automatically — see financial year invoice numbering for why this matters and how to migrate.

Further reading

• BOQ vs fee-based billing
• Construction management software — how Blueprint ships this by default.