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CGST ITC Rules Master Class: Rules 36, 37, 42, 86A & 86B Explained

July 24, 202610 min readAkib Husain

Quick Answer: What are the Core CGST Rules Governing Input Tax Credit?

CGST ITC Rules enforce strict compliance: Rule 36 requires invoice details in GSTR-2B; Rule 37 mandates 180-day payment reversal with 18% interest; Rule 42 covers exempt supply reversals; Rule 86A empowers credit ledger blocking; and Rule 86B mandates 1% cash liability payment for turnover over Rs 50 Lakh/month.

  • Rule 37 requires ITC reversal + 18% interest if supplier is unpaid past 180 days.
  • Rule 86B mandates 1% cash tax payment for monthly taxable sales over Rs 50 Lakhs.
  • Rule 42 calculates proportionate ITC reversal for common inputs used in exempt sales.
  • TallyPrime tracks unpaid bills past 180 days for automated Rule 37 statutory journal entries.

1. Master Summary Table of CGST ITC Rules

RuleMandate & ConditionsAction Required in GSTR-3B
Rule 37Non-payment to supplier within 180 days from invoice date.Reverse ITC in Table 4B(2) + pay 18% interest p.a.
Rule 86BMonthly taxable sales > Rs 50 Lakhs requires 1% cash payment.Pay minimum 1% output tax liability via Cash Ledger.

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Akib HusainExpert Reviewer

Founder & Chief Architect of TrulyInvoice

Last Verified: July 24, 2026
TallyPrime FY 2026-27 (v4.0+)
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