GST Set-Off Calculator
Enter your output tax liability and available ITC under each head. This applies the legal set-off order — IGST credit first, then CGST and SGST within their own heads — and shows your net cash payable and any credit carried forward.
| Tax head | Output liability (₹) | Available ITC (₹) |
|---|---|---|
| IGST | ||
| CGST | ||
| SGST / UTGST |
| Head | Liability | ITC set off | Cash payable |
|---|---|---|---|
| Total cash payable |
Filing this month? Check your return due dates, or work out any late fee and interest.
Convert Invoices to ExcelThe GST set-off order in one line
Use IGST credit first — against IGST, then CGST, then SGST — and finish it completely before touching CGST or SGST credit. CGST credit then pays CGST and any leftover IGST; SGST credit pays SGST and any leftover IGST. CGST credit can never pay SGST, and SGST credit can never pay CGST. Whatever liability is left after all eligible credit is set off, you pay in cash.
The utilisation order (Rule 88A / Section 49A)
| Credit held | 1st: pay this | 2nd: then this | Cannot pay |
|---|---|---|---|
| IGST credit | IGST | CGST & SGST (any order) | — |
| CGST credit | CGST | IGST | SGST / UTGST |
| SGST / UTGST credit | SGST / UTGST | IGST | CGST |
The one hard rule that trips people up: IGST credit must be fully utilised before any CGST or SGST credit is used (Section 49A, read with Rule 88A). The calculator above applies exactly this order.
Why you can owe cash while holding credit
Input tax credit is head-restricted. CGST credit can only ever pay CGST (and IGST); SGST credit can only ever pay SGST (and IGST). So if your sales are mostly local (CGST + SGST) but your purchases were mostly inter-state (IGST credit), or vice-versa, credit can pile up under one head while you still pay cash under another. This is normal and legal — the credit is not lost, it carries forward to the next month.
How to read the result
- Cash payable — the amount that must go through the electronic cash ledger for each head. Add them up for your total challan.
- ITC set off — credit applied to that head this period, in the legal order.
- Carried forward — unused credit left in the electronic credit ledger, available next month.
The tool applies IGST credit to CGST before SGST. In practice Rule 88A lets you split that IGST credit between CGST and SGST in any proportion — a smarter split can sometimes reduce the cash you pay by avoiding stranded credit under one head.
A worked example
Say your liability is IGST ₹10,000, CGST ₹10,000, SGST ₹10,000, and your ITC is IGST ₹20,000, CGST ₹5,000, SGST ₹5,000.
- IGST credit ₹20,000 → pays IGST ₹10,000, then CGST ₹10,000 (fully used). CGST liability now nil.
- CGST credit ₹5,000 → no CGST liability left, so it pays leftover IGST (none) — carries forward ₹5,000.
- SGST credit ₹5,000 → pays SGST ₹5,000 of the ₹10,000. Remaining SGST ₹5,000 is paid in cash.
Net cash payable: ₹5,000 (SGST), with ₹5,000 CGST credit carried forward — a classic head-mismatch outcome.
Related Tools
- GST Calculator — add or remove GST with the CGST/SGST/IGST split
- GST Return Due Dates — GSTR-1, GSTR-3B, QRMP, and annual deadlines
- GST Late Fee Calculator — late fee for a delayed return
- GST Interest Calculator — interest on delayed tax payment
Building your GSTR-3B from invoices?
Pull every purchase and sales invoice into one Excel sheet — upload the PDFs and extract GSTIN, tax, and totals automatically, then total your ITC and liability.
Convert to ExcelFrequently Asked Questions
What is the order of set-off for GST input tax credit?
IGST credit is used first — against IGST, then CGST and SGST in any order — and must be fully exhausted before CGST or SGST credit is touched (Section 49A with Rule 88A). CGST credit then pays CGST, then IGST. SGST/UTGST credit pays SGST, then IGST. CGST can never pay SGST and SGST can never pay CGST.
Can CGST credit be used to pay SGST liability?
No. CGST credit only pays CGST and then IGST — never SGST or UTGST. SGST credit likewise never pays CGST. This cross-utilisation bar is why cash can be due under one head while credit builds under another.
Why do I pay GST in cash even though I have unused ITC?
Credit is head-restricted. If your SGST liability is high but you mostly hold CGST credit, that CGST credit cannot pay the SGST, so SGST is paid in cash while the CGST credit carries forward. Splitting IGST credit sensibly between CGST and SGST can reduce the mismatch.
How is net GST payable calculated in GSTR-3B?
For each head, net cash = output liability minus ITC set off in the legal order. IGST credit applies first, then CGST and SGST within their heads and to IGST. Whatever remains is paid in cash through the electronic cash ledger; unused credit carries forward.
Can I choose how to split IGST credit between CGST and SGST?
Yes. Once IGST liability is covered, Rule 88A lets you apply IGST credit to CGST and SGST in any proportion. A sensible split can avoid stranding credit and reduce cash paid. The only hard rule is that IGST credit must be fully used before CGST or SGST credit.