GSTR-6 sheet for CA firms: ISD credit distribution for October 2026 by 13 November (one row per invoice per unit, C1 = t1/T x C)

Updated 24 Oct 2026 · Disclosure: the white-label calendar linked below is an Unadhi product (₹999/year). This guide is for information only, not professional advice.

What you get: a ready-to-copy Google Sheet layout for an Input Service Distributor (ISD) client. Tab 1 has one row per input-service invoice the ISD office received in October. Tab 2 has one row per unit (GSTIN) with its turnover for the relevant period. Tab 3 has one row per invoice per unit: by formula it works out each unit's share (C1 = t1/T × C), whether the unit gets CGST + SGST or IGST, and a check that nothing is over- or under-distributed. You also get a made-up example, a plan to Fri 13 November 2026 (GSTR-6 for October) and a WhatsApp message for clients.

Short answer (checked 24 Oct 2026): from 1 April 2025, an office of a business that receives tax invoices for input services (including reverse-charge services) for or on behalf of its other GSTINs under the same PAN must register as an ISD and distribute that credit (section 20(1) CGST Act, as substituted by the Finance Act 2024). Credit available in a month is distributed in the same month and reported in Form GSTR-6, due by the 13th of the next month, so 13 November 2026 for October 2026. A nil GSTR-6 is still required when there is nothing to distribute.

What the rules say

• Who must register, section 20(1). "Any office of the supplier ... which receives tax invoices towards the receipt of input services, including invoices in respect of services liable to tax under sub-section (3) or sub-section (4) of section 9 ... for or on behalf of distinct persons referred to in section 25, shall be required to be registered as Input Service Distributor under clause (viii) of section 24 and shall distribute the input tax credit in respect of such invoices." Section 12 of the Finance Act 2024 substituted this section with effect from 1 April 2025 (Notification 16/2024-Central Tax).
• Central tax and integrated tax, section 20(3). Central tax is distributed as central tax or integrated tax, and integrated tax as integrated tax or central tax, through a document showing the credit distributed.
• Same month, rule 39(1)(a)-(b). Credit available for distribution in a month is distributed in the same month and reported in GSTR-6. The amount distributed cannot exceed the credit available.
• Who gets it, rule 39(1)(c)-(f). Credit for a service used by one unit goes only to that unit. Credit for a service used by some or all units is shared pro rata on each unit's turnover in its State or UT during the relevant period: C1 = (t1 / T) × C. Units that make exempt supplies or are not registered are counted in T too.
• Relevant period (Explanation to rule 39). The previous financial year if the recipients had turnover in it, so FY 2025-26 for credit distributed in October 2026. If some or all recipients had no turnover in that year, use the last quarter for which turnover of all recipients is available before the month of distribution.
• Eligible and ineligible, rule 39(1)(g)-(h). Ineligible credit (for example under section 17(5)) and eligible credit are distributed separately, and each tax head separately.
• Which head the unit gets, rule 39(1)(i)-(j). IGST credit goes out as IGST to every unit. CGST and SGST/UTGST go out as CGST and SGST/UTGST to a unit in the same State as the ISD, and as IGST (equal to CGST + SGST) to a unit in another State.
• Documents, rule 39(1)(k)-(n). The ISD issues an ISD invoice (rule 54(1)) marked as issued only for distribution of credit, and an ISD credit note when distributed credit is reduced. A supplier's credit note is apportioned in the same ratio as the original invoice. If the amount comes out negative, it is added to the unit's output tax liability.
• Reverse-charge services, rule 39(1A). A unit with the same PAN and State code as the ISD that paid tax under reverse charge on common input services may issue an invoice or note under rule 54(1A) to pass that credit to the ISD, which then distributes it under rule 39(1). The GSTR-6 FAQ (Q10) adds that reverse charge liability does not apply to the ISD registration itself.
• Return, section 39(4) and the portal. An ISD files a return for every calendar month or part of a month within thirteen days after the end of the month. The FAQ says GSTR-6 is mandatory every month (nil if nothing is distributed), can be filed even if suppliers have not filed GSTR-1, has no electronic credit ledger, and needs DSC for companies and LLPs. Table 3 is for invoices received, Table 6B for credit and debit notes, and Tables 5 and 8 for ISD invoices and ISD credit notes.
• Late fee. Section 47(1) sets ₹100 a day up to ₹5,000 for a late section 39 return. The portal shows the amount in Table 10 after filing, and the FAQ (Q29) says it is for the current period only. We did not check for any waiver notification for GSTR-6, or for the State/UT part, so check before you quote a figure to a client.

Tab "Inward": one row per input-service invoice received by the ISD

Tab "Units": one row per GSTIN under the same PAN

Tab "Distribution": one row per invoice per unit that uses the service

Name the cell with the ISD's State ISD_STATE (for example in a Settings tab).

Rounding can leave a rupee or two. Adjust it on the largest unit's row so the total distributed equals the credit available (rule 39(1)(b)).

Made-up example

Client Z has its head office registered as an ISD in Karnataka and units in Karnataka, Maharashtra and Telangana (same PAN). In October 2026 the head office receives an invoice for software used by all three units: CGST ₹9,000 + SGST ₹9,000, eligible. FY 2025-26 turnover: Karnataka unit ₹6 crore, Maharashtra ₹3 crore, Telangana ₹1 crore, all operational, so T = ₹10 crore.

Three ISD invoices go out in October and the lot is reported in GSTR-6 for October by Fri 13 November 2026. (Example names and figures only.)

Plan to 13 November

WhatsApp message to a client

"Hello [name], your head office ISD registration must distribute October's credit on common services (audit, software, advertising and similar) to your other GSTINs, and GSTR-6 for October is due by 13 November. Please send us all October invoices received at head office and each unit's FY 2025-26 turnover by 5 November. A nil return is needed even if there is nothing to distribute. Thank you."

Related guides

• November 2026 due-date chase list
• IMS invoice action sheet for October 2026
• Blocked credit under section 17(5)
• ITC time limit under section 16(4)
• GSTR-7 sheet for October 2026

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Sources

• CGST Act section 20 (CBIC tax information portal, current text)
• Notification 16/2024-Central Tax, 6 August 2024 (sections 11 and 12 of the Finance Act 2024 in force from 1 April 2025)
• CGST Rules rule 39 (CBIC tax information portal, current text)
• CGST Act, 2017 (CBIC updated text): sections 39(4), 47(1)
• GST portal FAQs on Form GSTR-6 and GSTR-6 user manual

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