GST Payment & Liability Calculator Free Excel Template for Indian Businesses

Enter your output tax and input credit for the period. Get the set-off applied in the order the law prescribes, the cash payable under each head, and the interest and late fee if you are filing late. Updated for FY 2026-27.

Credit set-off applied under Section 49A and Rule 88A, with a 20 step working you can audit
Cash payable head-wise, laid out like Table 6.1 of GSTR-3B
Interest on the cash portion only, late fee capped by your turnover band

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Petpooja presents

GST Payment & Liability Calculator

For Indian Businesses

Sheets · Excel template

FY 2026-27

What's Inside

Six sheets that turn your tax figures into one challan amount

Liability and Credit Input Sheet

The sheet you fill in first: output tax head-wise, reverse charge liability, opening credit balances, credit for the period, and anything already lying in your cash ledger.

Credit Utilisation Matrix

The set-off laid out exactly like Table 6.1 of GSTR-3B. IGST, CGST, SGST and cess credit against each liability head, with the cash line at the bottom.

20 Step Set-Off Working

Every figure in the matrix traced back to a numbered step, and the section, rule or circular named on each step that turns on law. Nothing is hidden inside a formula you cannot check.

Interest and Late Fee Sheet

Due date auto-set for monthly or QRMP filing. Interest at 18 percent on the cash portion, late fee at the daily rate, capped by your turnover band.

Head-wise Payment Summary

Tax, reverse charge, interest and late fee added up under each head, less your cash ledger balance. The last column is what you deposit through PMT-06.

Rule 86B Check and Walkthrough

Flags the 1 percent cash rule in a month when taxable supplies cross ₹50 lakh, and a worked example that explains every number in the sample return.

Do all of this automatically with Petpooja Invoice

Petpooja Invoice records every sale and purchase with the right tax head and HSN code, and syncs to Tally, so your output tax and input credit are ready on return day instead of being rebuilt from a pile of bills.

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Why This Matters

The tax you collected is not the tax you pay

You charged ₹5,94,000 of tax on your sales this month. You hold ₹5,64,000 of input credit. So you owe ₹30,000, right? Not quite. The answer depends on which head the credit sits under and which head the liability sits under.

GST is one indirect tax with three or four separate wallets: IGST, CGST, SGST or UTGST, and compensation cess. Credit under one head cannot always pay a liability under another. That is where a return that looks balanced on paper turns into a real cash outgo.

The rules are specific. IGST credit has to be used before CGST or SGST credit is touched, under Section 49A of the CGST Act. CGST credit can never pay SGST liability and the reverse is equally barred. Reverse charge tax has to be paid in cash even when your credit ledger is full.

Inside those rules sits one choice that is genuinely yours. Rule 88A, as CBIC spells out in Circular 98/17/2019-GST, lets you apply leftover IGST credit against CGST and SGST liability in any order and in any proportion. Send it to the head that already has enough credit of its own and you pay cash for no reason, while credit sits idle in the ledger.

In the sample month in this workbook, that single choice is the difference between depositing ₹36,000 and depositing ₹1,44,000. Same sales, same purchases, same credit. Only the allocation changed.

A leak like that never appears as a line in your books. It shows up as credit piling up in the ledger while the bank balance thins, which is one of the quieter ways small retail shops lose profit without noticing.

Then there is the cost of being late. Interest under Section 50(1) runs at 18 percent a year, but only on the part of the tax you actually pay in cash, as Rule 88B(1) makes clear. Late fee is separate, runs per day, and applies even to a nil return.

This calculator does the whole sequence in one place. Enter the figures from your sales and purchase records, and it applies the set-off order, works out the cash payable head-wise, adds interest and late fee for the days you are late, and flags the Rule 86B position before the portal does.

One thing to settle before you start: whether you can claim credit at all. A food business billing at the 5 percent rate cannot, and the GST rules for restaurants work differently from those for a retailer or a manufacturer on that count.

It is built for the way Indian SMEs actually file: a monthly GSTR-3B or a quarterly return under QRMP, one GSTIN at a time, with the numbers coming from a billing register rather than an ERP.

Sample Preview

What the calculator shows for a June 2026 return

Here's a preview of what you'll get inside:

Output tax for the month: IGST ₹1,44,000, CGST ₹2,25,000, SGST ₹2,25,000. Total ₹5,94,000 on sales of ₹33,00,000

Credit applied: IGST credit of ₹2,52,000 clears the IGST liability first, then ₹1,08,000 of it moves to CGST, the head that is short

Cash payable on tax: ₹36,000 under CGST. IGST and SGST are fully settled through credit, with ₹6,000 of SGST credit left to carry forward

Reverse charge: ₹9,000 on goods transport freight, payable in cash under Section 49(4) even though the credit ledger still had a balance

Filed seven days late: interest of ₹148.43 on the cash portion only, plus a late fee of ₹350 at ₹50 a day, well inside the ₹5,000 cap

... plus the head-wise challan amount of ₹43,498.43, the closing credit balances for next month, and the Rule 86B position, across 6 sheets.

Key Stats

The three numbers that decide what a late return costs you

18% a year

Interest on delayed payment under Section 50(1). It runs on the tax paid by debiting the cash ledger, not on the part settled through credit, which is why the set-off order changes your interest as well as your outgo.

Source: Section 50(1) of the CGST Act read with CBIC Rule 88B(1)

₹50/day

Late fee for a delayed GSTR-3B, being ₹25 under CGST and ₹25 under SGST. A nil return is ₹20 a day. The ceiling runs from ₹500 for a nil return to ₹10,000 above ₹5 crore of turnover.

Source: Notification 76/2018-Central Tax and Notification 19/2021-Central Tax

₹50 lakh

Monthly taxable supply above which Rule 86B applies. Cross it and at least 1 percent of the output tax liability has to be paid in cash, however much credit you are holding, unless a listed exception fits you.

Source: Rule 86B of the CGST Rules, filed through the GST portal

Common Mistakes

7 GST payment mistakes Indian businesses make

Sending leftover IGST credit to the wrong head

Rule 88A leaves the CGST and SGST split to you. Push the credit into a head that already has enough of its own, and you pay cash under the other head while credit sits idle. In the sample month, that mistake costs ₹1,08,000.

Paying reverse charge tax out of the credit ledger

Section 49(4) bars it. Tax under reverse charge is payable in cash, and the credit for it comes back to you only in the same or a later period. Businesses paying freight, legal fees or director remuneration hit this every month.

Setting off against credit that is not in GSTR-2B yet

Credit your supplier has not reported is not yours to use. Set off against it and the shortfall surfaces as tax plus interest later. Reconcile your input tax credit first, then run the set-off on what survives.

Assuming interest runs on the whole liability

It does not. Rule 88B(1) charges interest on the portion paid by debiting the cash ledger for a return filed after the due date. Money already credited to the cash ledger before the due date, and left there, is excluded.

Treating a nil month as nothing to file

Late fee is charged for the delay in filing, not for the tax. A nil return still runs at ₹20 a day up to ₹500. Skip it for a few months and the fee arrives without a single rupee of tax being due, so keep the GST return filing checklist somewhere you will see it.

Ignoring which head your credit is piling up in

Where CGST and SGST credit both go to an IGST liability, the prescribed order takes the CGST side first, so SGST credit keeps building. Months later it is stranded while CGST liability needs cash. The lever you do control is the IGST split, so aim it at the head that is short.

Forgetting Rule 86B in a strong month

Cross ₹50 lakh of taxable supply in a month and at least 1 percent of output tax has to move in cash, whatever your credit balance. It is tested month by month, so one good month can pull you in without warning. Your ledger position on the GST portal tells you where you stand.

Comparison

Working it out on the portal vs this calculator

Aspect	On the portal, at filing time	With this calculator
When you learn the number	After you have logged in and filled the return	Before you log in, so the money can be arranged
IGST credit split between CGST and SGST	Suggested, and usually accepted without checking	Allocated to the head that is short, with the working shown
Why a figure is what it is	Not explained	Traced through 20 numbered steps, each legal one citing its provision
Interest on late payment	Computed at the end, on the portal's basis	Estimated up front on the cash portion, net of ledger balance
Late fee ceiling	Applied silently	Shown against your turnover band before you file
Rule 86B position	Surfaces as a filing block	Flagged with the minimum cash figure while you can still act
Next month's opening balances	Looked up again from the ledger	Carried out as closing balances, head-wise

Know the challan amount before you open the portal

Download the free calculator, enter your figures for the period, and see the cash payable head-wise.

FAQ

Frequently asked questions

How is GST payable in cash actually calculated?

Start with output tax for the period, head-wise. Apply input credit in the order Section 49, 49A and 49B allow, so IGST credit first, then CGST credit against CGST liability and SGST credit against SGST liability, with the remainder of each usable against IGST. Whatever liability survives is paid in cash, and reverse charge tax is added to that cash figure because credit cannot be used for it. If you want to check a single invoice or a rate before this stage, the free GST calculator handles that side.

In what order can input tax credit be set off?

IGST credit has to be exhausted before CGST or SGST credit is used at all, under Section 49A. IGST credit pays IGST liability first, and the balance can be applied against CGST and SGST liability in any order and in any proportion, under Rule 88A read with Circular 98/17/2019-GST. CGST credit then pays CGST liability and any balance can go to IGST liability, with SGST credit working the same way on its side. Where both are applied to an IGST liability, that circular puts CGST credit ahead of SGST credit. CGST credit can never pay SGST liability and SGST credit can never pay CGST liability.

Can I pay reverse charge tax using input tax credit?

No. Section 49(4) allows the electronic credit ledger to be used only for output tax, and tax payable under reverse charge has to be discharged in cash. You claim the credit for it afterwards, in the same or a later period, subject to the usual eligibility conditions. This is why a business with a healthy credit balance can still have a cash outgo every month.

How much interest and late fee apply if GSTR-3B is filed late?

Interest under Section 50(1) is 18 percent a year, charged on the tax paid by debiting the cash ledger for the days of delay, as set out in Rule 88B(1). Late fee under Section 47 is ₹25 a day under CGST plus ₹25 under SGST, so ₹50 a day, and ₹20 a day for a nil return. The ceiling is ₹500 for a nil return, ₹2,000 up to ₹1.5 crore of turnover, ₹5,000 between ₹1.5 crore and ₹5 crore, and ₹10,000 above ₹5 crore, per Notification 19/2021-Central Tax.

What is Rule 86B and does it apply to my business?

Rule 86B applies in any month where your taxable supply, leaving out exempt and zero-rated supply, is more than ₹50 lakh. In that month you cannot discharge more than 99 percent of output tax liability through credit, so at least 1 percent moves in cash. Exceptions include paying more than ₹1 lakh of income tax in each of the last two financial years, receiving a refund above ₹1 lakh on zero-rated supplies or an inverted duty structure, having already paid more than 1 percent of your output tax in cash cumulatively this financial year, and government bodies. Note that if you run a restaurant on the 5 percent rate without credit, the whole set-off question changes, as covered in GST billing for restaurants.

About Petpooja

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