Returns: formula sheet

Key formulas

Legal basis

Section 37 CGST Act, 2017 + Rule 59

Every registered person other than ISD, composition dealer, non-resident taxable person, OIDAR supplier and TDS/TCS deductor furnishes outward supply details.

Due date: monthly filer

11th of the month following the tax period

Example: GSTR-1 for June is due on 11 July.

Due date: QRMP filer

13th of the month following the quarter

Example: quarter July to September is due on 13 October.

IFF due date and limit

13th of next month; B2B supplies up to ₹50 lakh per month (months 1 and 2 of quarter)

Optional. Not available for the third month of the quarter.

QRMP eligibility

Aggregate turnover ≤ ₹5 crore in the preceding financial year

Tax for the first two months of the quarter is paid by the 25th of the next month through PMT-06. Tax for the third month is paid with the quarterly GSTR-3B, due on the 22nd or 24th of the month after the quarter, depending on the state.

B2C large test

Inter-state supply to unregistered person AND invoice value > ₹2,50,000

Reported invoice-wise. All other B2C supplies are consolidated state-wise and rate-wise. The limit of ₹2.5 lakh applies from 15 November 2024; the earlier limit of ₹1 lakh no longer applies.

Filing condition (Rule 59(6))

GSTR-1 cannot be furnished if GSTR-3B for the immediately preceding tax period has not been furnished

For a monthly filer, the preceding tax period is the preceding month. For a QRMP filer, it is the preceding quarter. The restriction does not apply to filing under IFF.

Amendment rule

Correct in the return for the month the error is noticed

Last date: earlier of the due date of the September return following the financial year end, or the actual date of furnishing the annual return (section 37(3)). Interest on tax short paid is levied under section 50, not under section 37(3).

Rule for claiming ITC on invoices

ITC claimed in GSTR-3B = Eligible ITC reflected in GSTR-2B (after Section 16 and 17 checks) + ITC on reverse charge, imports and other items allowed from books

Invoices not in GSTR-2B are not claimed now. Claim them in the month they appear in GSTR-2B, within the Section 16(4) time limit.

GSTR-2A vs GSTR-2B

GSTR-2A = dynamic, read-only, updates continuously | GSTR-2B = static, monthly, generated once

Use GSTR-2B for claiming ITC. Use GSTR-2A to track what suppliers have filed.

Section 16(2)(aa)

ITC allowed only if supplier has furnished invoice details in GSTR-1 or IFF and they are communicated to you in GSTR-2B

Section 16(2)(aa) was inserted by the Finance Act 2021 and took effect from 1 January 2022. Rule 36(4), the earlier provisional-claim limit, was omitted w.e.f. 1 January 2022. The Finance Act 2022 amended Section 16(2)(aa) w.e.f. 1 October 2022 so that it refers to communication of the details in GSTR-2B. From the same date, the Finance Act 2022 substituted Section 41 (self-assessed ITC claim in the return), omitted Section 41A, and omitted Sections 42, 43 and 43A.

Reconciliation

ITC per books − ITC per GSTR-2B = timing differences + ineligible items + RCM and other items not in 2B + errors

Work through each difference. Do not net them off.

Rule 37 reversal for non-payment

ITC to reverse = ITC on the invoice × (Unpaid amount including tax ÷ Invoice value including tax)

Applies when you do not pay the supplier within 180 days from the date of the invoice. Add the amount to your output tax liability in the GSTR-3B for the month immediately following the 180-day period. Interest under Section 50 applies. You can reclaim the credit once you pay.

Time limit for ITC

ITC on an invoice or debit note must be taken by 30 November following the end of the financial year to which the invoice or debit note pertains (the annual-return-filing limb was removed w.e.f. 1 October 2022)

This is the Section 16(4) deadline. The year that counts is the one to which the invoice pertains, not the year of the claim. It applies even if the invoice shows in GSTR-2B late.

Monthly due date

20th of the next month

For regular taxpayers who are not under QRMP. Some notified classes of taxpayers get extended dates by notification, so follow the date given in the question.

QRMP quarterly due date

22nd or 24th of the month after the quarter ends

Available if aggregate turnover in the preceding financial year was up to ₹5 crore. The date depends on the State or Union territory. Tax for months one and two is paid by the 25th through PMT-06.

Cash tax payable

Output tax liability (incl. RCM) − ITC utilised = Cash payment

RCM tax cannot be paid from the credit ledger. It is always paid in cash.

Net ITC (Table 4C)

Net ITC = Table 4(A) ITC available − Table 4(B) ITC reversed

Table 4(D) shows ineligible ITC for information. It is not part of net ITC.

Interest on late payment

Interest = Tax paid late × 18% × days of delay ÷ 365

Counted from the day after the due date to the date of payment. It is charged on the tax payable in cash after ITC set-off, not on the gross liability.

Interest on ITC wrongly availed and utilised

Interest = Excess ITC × 24% × days ÷ 365

Applies when ITC is wrongly availed and utilised, or excess ITC is claimed and utilised.

Late fee (statutory rate)

₹50 per day (₹25 CGST + ₹25 SGST); ₹20 per day for a nil return (₹10 + ₹10); maximum ₹10,000 per return (₹5,000 + ₹5,000)

Government has reduced the daily fee and caps for many classes of taxpayers by notification, based on turnover and on whether the return is nil. If the question gives concessional rates, use them.

Revision of GSTR-3B

Not allowed

Declare short-reported liability in a later period's return, with interest on the delayed tax.

CMP-08

Composition dealer | Quarterly | Due: 18th of the month after the quarter

It is a statement-cum-challan used to pay self-assessed tax. Example: for July to September, the due date is 18 October.

GSTR-4

Composition dealer | Annual | Due: 30 April after the financial year

It reports turnover, tax paid through CMP-08 and inward supplies. It is not a monthly or quarterly return.

GSTR-5

Non-resident taxable person | Monthly | Due: 13th of next month, or within 7 days after the registration expires, whichever is earlier

It is filed for each month of registration, including nil months.

GSTR-5A

OIDAR service provider outside India | Monthly | Due: 20th of next month

The supplies are to non-taxable persons in India.

GSTR-6

Input Service Distributor | Monthly | Due: 13th of next month

It shows credit received and credit distributed.

GSTR-7

TDS deductor | Monthly | Due: 10th of next month

TDS under section 51 applies where the total value of the taxable supply of goods or services under a contract exceeds ₹2.5 lakh. It is deducted from payments to the supplier. Tax is deducted at 2% (1% CGST + 1% SGST for an intra-state supply, or 2% IGST for an inter-state supply) of the payment value, excluding GST.

GSTR-8

E-commerce operator liable under section 52 | Monthly | Due: 10th of next month

TCS = rate × (value of taxable supplies through the platform − returns). The notified TCS rate is 0.5% (0.25% CGST + 0.25% SGST for an intra-state supply, or 0.5% IGST for an inter-state supply).

Annual return exemption

ISD, TDS/TCS persons, casual and non-resident taxable persons do not file GSTR-9

Their monthly or periodic returns are their only returns. Composition dealers file GSTR-4 as their annual return.

Who files GSTR-9 (section 44)

Every registered person, except an ISD, a casual taxable person, a non-resident taxable person, and a person paying tax under section 51 or section 52

A composition taxpayer is not excluded by section 44 itself. Its annual return is Form GSTR-4 under Rule 62, which replaced GSTR-9A from FY 2019-20.

GSTR-9 small taxpayer relief

Aggregate turnover ≤ ₹2 crore in the financial year → filing exempt (by notification)

Check the year in the question. The relief is by notification, not part of section 44 itself.

GSTR-9C applicability

Aggregate turnover > ₹5 crore → self-certified reconciliation statement in GSTR-9C

No CA/CMA audit or certification is needed now. At exactly ₹5 crore it is not required.

Due date of GSTR-9 and GSTR-9C

31 December following the end of the financial year

For 2026-27 this is 31 December 2027. The Government can extend it by notification.

Late fee for GSTR-9 (section 47(2))

₹200 per day (₹100 CGST + ₹100 SGST) subject to a maximum of 0.25% of turnover in the State or UT under each Act (0.5% in total)

Reduced slabs apply by notification. Aggregate turnover up to ₹5 crore: ₹50 per day (₹25 CGST + ₹25 SGST), cap 0.04% of turnover in the State or UT (0.02% + 0.02%). Above ₹5 crore up to ₹20 crore: ₹100 per day (₹50 + ₹50), cap 0.08% (0.04% + 0.04%). Above ₹20 crore, the standard ₹200 per day and the 0.25% per Act cap (0.5% in total) apply. Use the slabs only if the question gives them.

GSTR-10 final return (section 45, Rule 81)

Due within 3 months of the date of cancellation or the date of the cancellation order, whichever is later

Rule 81 requires it from a registered person whose registration is cancelled or surrendered, other than an ISD, a person paying TDS/TCS or a non-resident taxable person. Casual taxable persons and composition taxpayers are covered.

Aggregate turnover (section 2(6))

Aggregate value of all taxable supplies (excluding inward supplies on reverse charge), exempt supplies, exports of goods or services, and inter-State supplies, of persons having the same PAN, computed on an all-India basis; excludes CGST, SGST, IGST and cess, and excludes non-taxable supplies

Exempt supplies are included, but non-taxable supplies, such as supplies of alcohol for human consumption, are not. Inter-State supplies are counted within these categories, not added again. It covers supplies made by the person, not purchases. Count each supply once. Use this figure, not the State turnover, for the thresholds.

Statutory late fee (Section 47)

₹100 per day (CGST) + ₹100 per day (SGST/UTGST) = ₹200 per day; maximum ₹5,000 under each Act

Counted from the day after the due date to the date of filing. Use this only when the question gives no rate. Notified rates for GSTR-1 and GSTR-3B are lower.

Notified late fee (GSTR-1 and GSTR-3B)

Normal return: ₹50 per day (₹25 CGST + ₹25 SGST/UTGST); nil return: ₹20 per day

Subject to notified caps. If the question gives a rate and cap, use them.

Interest on delayed tax (Section 50)

Interest = Tax payable in cash × 18% × Days of delay ÷ 365

Days run from the day after the due date to the date of payment. Where the return is furnished late, the base is the tax payable in cash, net of ITC available in the electronic credit ledger.

Interest on undue or excess ITC, or excess reduction in output tax

Interest = Undue or excess ITC availed and utilised (or excess reduction in output tax liability) × 24% × Days ÷ 365

The higher rate under Section 50(3) applies only to that amount, and for the period of the wrong use or reduction.

Nil return rule

No supplies + no ITC + no liability = nil return, still compulsory

Late filing of a nil return still attracts late fee, at the notified lower amount of ₹20 per day if the question gives it.

Registration cancellation trigger

Regular taxpayer: 6 continuous months of non-filing; Composition: 3 consecutive tax periods

Cancellation by the proper officer under Section 29.

E-way bill restriction (Rule 138E)

Regular taxpayer: GSTR-3B not filed for a continuous period of 2 months or more; Composition taxpayer: Form GST CMP-08 statement not filed for a tax period

Generation of outward e-way bills is restricted till the default is cured.

Time bar on filing

GSTR-1, GSTR-3B and annual return: not after 3 years from the due date (Sections 37, 39 and 44, as inserted by the Finance Act 2023)

Does not extend to all returns. Check the return and the notified provisions in the question.

Quick revision

• GSTR-1 reports outward supplies under Section 37; GSTR-3B is the summary return with payment under Section 39.
• GSTR-2B is a static auto-drafted credit statement; GSTR-2A is dynamic and changes as suppliers file.
• Section 16(2)(aa) allows credit only if the supplier has furnished the invoice or debit note details in GSTR-1 or IFF and they are communicated to you in the statement under Section 38 (GSTR-2B). This is one condition. The other Section 16 conditions must also be met: tax invoice or debit note, receipt of the goods or services, tax paid to the government, and the return filed.
• Composition taxpayers pay tax quarterly through CMP-08 and file GSTR-4 annually. GSTR-9A was earlier the annual return for composition taxpayers, but it was discontinued from FY 2019-20.
• TDS return is GSTR-7 and TCS return is GSTR-8; ISD return is GSTR-6.
• Non-resident taxable persons file GSTR-5; OIDAR service providers outside India file GSTR-5A.
• The QRMP scheme is optional. It is available to registered persons who are required to file GSTR-1 and GSTR-3B and whose aggregate turnover in the preceding financial year was up to ₹5 crore. Those who opt in file GSTR-1 and GSTR-3B quarterly and pay tax monthly through PMT-06. They may use the optional IFF to report supplies for the first two months of the quarter.
• Annual return GSTR-9 is under Section 44. For certain specific years, filing GSTR-9 was made optional by notification for taxpayers with aggregate turnover up to ₹2 crore. This is not a general rule for every year, so check the notification for the relevant year in your question.
• GSTR-9C is a self-certified reconciliation statement. It is filed only by taxpayers whose aggregate turnover exceeds the notified limit, currently ₹5 crore for the years notified. Check the notification for the relevant year. This is a different limit from the QRMP limit, even though both figures are ₹5 crore. Since FY 2020-21, certification by a CA/CMA is no longer required.
• Late fee under Section 47 is a per-day amount under the CGST Act, with an equal amount levied under the SGST/UTGST Act. No IGST late fee applies. It has a maximum cap, so check the rates and cap against the notification for your attempt.
• Interest on late payment of tax under Section 50 is 18% per annum, counted from the day after the due date to the date of payment. For a delayed GSTR-3B, interest under the proviso to Section 50(1) is charged on the net cash tax liability, meaning the amount payable after input tax credit is utilised. This proviso applies retrospectively from 1 July 2017. A higher rate of 24% per annum applies to undue or excess input tax credit claimed and utilised, and to undue or excess reduction in output tax liability. Interest is not charged on input tax credit wrongly availed but not utilised.
• Nil returns must still be filed, and the late fee for them is lower than for returns with tax.
• Due dates and limits can be changed by notification, so confirm them against the study material for your attempt.

Common mistakes

• Writing 20th or 10th as the GSTR-1 due date. Fix: Remember the pair: GSTR-1 is 11th (monthly) or 13th (QRMP). GSTR-3B comes later.
• Thinking QRMP filers pay tax quarterly. Fix: Return is quarterly but payment is monthly. Tax for months 1 and 2 is paid by the 25th of the next month through PMT-06. Tax for the third month is paid with the quarterly GSTR-3B, due on the 22nd or 24th depending on the state.
• Treating GSTR-2A and GSTR-2B as the same statement. Fix: Remember the key difference: GSTR-2A is dynamic and read-only. GSTR-2B is static and generated once a month. Claim ITC based on GSTR-2B.
• Claiming ITC on an invoice only because it is in GSTR-2B. Fix: Still check Section 16 conditions, blocked credit under Section 17(5), receipt of goods or services, payment within 180 days and the time limit.
• Saying GSTR-3B can be revised if a mistake is found. Fix: Remember there is no revision. Declare any short-reported or omitted liability in a later period's GSTR-3B (generally in Table 3.1) and pay interest on the delayed tax. Where the error is in invoice-level outward supply details, the amendment tables of GSTR-1 can also be used.
• Charging interest on the total tax liability. Fix: Compute interest on the tax that was actually payable in cash, after ITC set-off, unless the question says otherwise.
• Saying GSTR-4 is a quarterly return for composition dealers. Fix: Remember the pair: CMP-08 is the quarterly payment statement, and GSTR-4 is the annual return due on 30 April.
• Mixing up the due dates of GSTR-5, 5A, 6, 7 and 8. Fix: Use the pattern 10-13-18-20. GSTR-7 and 8 are on the 10th, GSTR-5 and GSTR-6 are on the 13th, CMP-08 is on the 18th, and GSTR-5A is on the 20th. GSTR-5 is earlier if the registration expires sooner, namely within 7 days after expiry.
• Saying GSTR-9C needs a certificate from a Chartered Accountant. Fix: Write that GSTR-9C is a self-certified reconciliation statement, filed where aggregate turnover exceeds ₹5 crore.
• Applying GSTR-9C at exactly ₹5 crore. Fix: The law says 'exceeds ₹5 crore'. At ₹5 crore exactly, only GSTR-9 is required.

Exam tips

• Learn the numbers as a set: 11th, 13th, 25th, ₹5 crore, ₹50 lakh, ₹2.5 lakh. MCQs usually test one of these.
• In case studies, check the preceding year turnover first. It decides whether QRMP is available.
• For a written answer on amendments, name section 37(3), state that the original return is not revised, give the time limit, and mention that interest on short paid tax is under section 50.
• Do not mix GSTR-1 (details of supplies) with GSTR-3B (summary and payment). Say clearly which one carries tax payment.
• Use a short table-wise listing in the answer (B2B, B2CL, B2CS, exports, notes). It is quick to write and easy for the examiner to give marks.
• Write the GSTR-2A vs GSTR-2B difference in two crisp lines (dynamic vs static, read-only vs auto-drafted for ITC claim). This is a common short-answer point.
• For any ITC question, say Section 16(2)(aa) and GSTR-2B before giving the figure. This earns provision marks.
• Do not quote Sections 42 and 43 as current law. If a question uses them, state that the matching process was omitted and apply the present rule.