If your business has both taxable and exempt supplies, ITC cannot simply be claimed in full. Common input/input-service credit needs a disciplined reversal working under the GST credit rules.
Why Reversal Is Required
Section 17 restricts ITC to the portion attributable to business use and to taxable supplies including zero-rated supplies. Where inputs or input services are partly used for exempt supplies or non-business purposes, Rule 42 provides the method for identifying exclusive ineligible credit, eligible credit and common credit attributable to exempt/non-business use.
| Credit bucket | Meaning | Action |
|---|
| T1 / non-business use | Inputs/input services intended exclusively for non-business purposes | Do not credit / reverse. |
| T2 / exempt supplies | Inputs/input services intended exclusively for exempt supplies | Do not credit / reverse. |
| T3 / blocked credit | Items covered by Section 17(5) | Do not claim. |
| T4 / taxable supplies | Inputs/input services used exclusively for taxable/zero-rated supplies | Eligible subject to Section 16. |
| Common credit | Residual credit used commonly | Apply Rule 42 formula and annual true-up. |
Annual True-Up
Rule 42 also contemplates final calculation/adjustment after the financial year. Where finally calculated ineligible credit exceeds monthly reversal, the excess has to be reversed with applicable interest mechanics; where monthly reversal is higher, eligible excess may be reclaimed within the prescribed framework.
Monthly Close Control: How to Avoid Notices
- Download GSTR-2B and compare supplier GSTIN, invoice number, invoice date, taxable value and tax amount with books.
- Tag every variance as timing, supplier error, ineligible credit, RCM item, import/bill-of-entry item, amendment or duplicate.
- Do not claim credit merely because the vendor invoice is booked; apply Section 16 and Rule 36 controls.
- Create a vendor escalation list before GSTR-3B filing date rather than after receiving a mismatch notice.
- Keep a management-approved working paper for every credit claimed despite timing differences.
Best practiceMake the Rule 42 working part of monthly close. Waiting until annual return creates avoidable interest, cash-flow and audit issues.
Finin2min Publishing Checklist Before Upload
- Verify every legal statement against the official references below immediately before upload.
- Do not mention a GST rate unless the current rate schedule/notification is separately checked for that item or service.
- Add one Indian SME example from actual workflow — SaaS, agency, D2C, manufacturer, coworking, finance team or startup.
- Cross-link this article to GST registration, GST return, ITC reconciliation and GST notice-response pages.
- Keep the disclaimer because ITC treatment depends heavily on facts, invoices, contracts and portal status.
Official References Used
This draft uses official GST law, GST rules, GST portal and CBIC/GST Council sources only. Before publishing, re-check whether any notification, circular, rule text or portal workflow has changed after the draft date.
Frequently Asked Questions
When is ITC reversal required for exempt supplies? ▼
When inputs/input services are used partly for taxable/zero-rated supplies and partly for exempt supplies or non-business purposes.
Does zero-rated supply count as taxable for credit attribution? ▼
Section 17 refers to taxable supplies including zero-rated supplies for attribution purposes.
Should Rule 42 be done monthly or annually? ▼
The working is relevant monthly with final adjustment/true-up after the year as per the rule framework.