Taxation · Returns

GSTR-1: Details of Outward Supplies Under GST

Updated 4 October 2026 · Fact-checked

GSTR-1 is the return of outward supplies that a registered person files under section 37 of the CGST Act. Monthly filers file by the 11th of the next month. QRMP filers file quarterly by the 13th after the quarter. To solve questions, classify each supply, check the due date, then apply the amendment rules.

Understand GSTR-1: Details of Outward Supplies

GSTR-1 is a statement of all outward supplies made by a registered regular taxpayer in a tax period. It is required by section 37 of the CGST Act, 2017 and the manner is in Rule 59. It does not carry tax payment. Tax is paid through GSTR-3B. GSTR-1 is important because it feeds the recipient's GSTR-2A and GSTR-2B, so your buyer's input tax credit depends on it.

The return has invoice-level and summary-level data. Supplies to registered persons (B2B) are reported invoice by invoice. Inter-state supplies to unregistered persons with invoice value above ₹2,50,000 (B2C large) are also reported invoice by invoice. Other supplies to unregistered persons (B2C small) are reported in consolidated form, state-wise and rate-wise. Exports, supplies to SEZ, credit and debit notes, nil-rated, exempt and non-GST supplies, advances received, documents issued and the HSN summary also go in.

A regular taxpayer files GSTR-1 monthly by the 11th of the next month. Under the QRMP scheme (Quarterly Return, Monthly Payment), a person with aggregate turnover up to ₹5 crore in the preceding financial year can opt to file GSTR-1 quarterly, by the 13th of the month after the quarter. Tax is still paid every month. For the first two months of the quarter, you pay through challan PMT-06 by the 25th of the next month, either by the fixed sum method or the self-assessment method. Tax for the third month is paid with the quarterly GSTR-3B, which is due on the 22nd or 24th of the month after the quarter, depending on the state or Union territory of registration.

QRMP filers get the Invoice Furnishing Facility (IFF). It is optional. You can upload B2B supplies of the first and second month of the quarter by the 13th of the next month, so your buyers can claim credit early. The cap is ₹50 lakh of B2B supplies in each of the first two months. Anything not uploaded through IFF goes in the quarterly GSTR-1. IFF is not available for the third month, because the quarterly GSTR-1 covers it.

Errors in GSTR-1 are corrected through the amendment tables of a later GSTR-1, not by re-filing the old one. Section 37(3) allows rectification in the return for the month in which the error is noticed. The time limit is the earlier of two dates: the due date for furnishing the return for the month of September following the end of the financial year to which the details relate, or the actual date of furnishing the relevant annual return.

Section 37(3) deals only with the right and time limit for rectification. If the correction shows that tax was short paid, interest is levied separately under section 50 on the tax short paid. It is not computed under section 37(3).

Key rules to remember

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).

How to solve GSTR-1: Details of Outward Supplies questions

Use this order for any GSTR-1 question, whether it asks for due dates, contents or corrections.

1Identify the filer: regular monthly, QRMP quarterly, or someone not required to file GSTR-1 (composition dealer, ISD).
2Check eligibility facts: preceding year aggregate turnover against ₹5 crore for QRMP, and whether the option has been exercised.
3Classify every supply: B2B, B2C large, B2C small, export, SEZ, nil/exempt/non-GST, credit or debit note, advance received.
4Apply the table rule: invoice-wise for B2B and B2C large, consolidated for B2C small, and include the HSN summary.
5Fix the due date: 11th for monthly, 13th after the quarter for QRMP, 13th for IFF in months 1 and 2.
6If the question mentions an error, identify the original table and the correct amendment table, check the section 37(3) time limit, and if tax was short reported, state that interest is levied under section 50.
7Write the conclusion in one line: what is reported where, and by what date.

Quickest way: Classify, date, then amend

When to use it: Use this in MCQs and short-note questions where you have two to three minutes.

MCQ: look for the keywords 11th, 13th, ₹5 crore, ₹50 lakh and ₹2.5 lakh. Most options differ on these numbers, so eliminate by them.
If the person is a QRMP filer, remember: tax for months 1 and 2 by the 25th through PMT-06, third month's tax with the quarterly GSTR-3B (22nd or 24th), return quarterly by the 13th, IFF only for months 1 and 2.
For classification, ask two questions only: is the buyer registered, and is it inter-state above ₹2,50,000?
Written answer format: state the provision (section 37 and Rule 59), apply it to the facts, then conclude. Show the table name and the date separately so each earns a step mark.
In amendments, say clearly that the original return is not revised. The correction is made in a later GSTR-1, and any interest on short paid tax comes under section 50.

Common mistakes in GSTR-1: Details of Outward Supplies

Writing 20th or 10th as the GSTR-1 due date.
Students mix GSTR-1 with GSTR-3B, which has the 20th date for monthly filers, or recall old dates.
Fix: Remember the pair: GSTR-1 is 11th (monthly) or 13th (QRMP). GSTR-3B comes later.
Thinking QRMP filers pay tax quarterly.
The return is quarterly, so students assume the payment is too.
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.
Saying IFF can be used for all three months and for B2C supplies.
The word 'facility' feels broad.
Fix: IFF is optional, for B2B supplies only, in the first two months of the quarter, up to ₹50 lakh per month.
Reporting every B2C inter-state supply invoice-wise, or using the old ₹1 lakh limit.
Students forget the value test, or learn from older notes that still show ₹1 lakh.
Fix: Invoice-wise only if inter-state and invoice value exceeds ₹2,50,000. Otherwise consolidate state-wise and rate-wise.
Saying a filed GSTR-1 can be revised.
Income-tax returns can be revised, so students assume the same.
Fix: GSTR-1 cannot be revised once filed. Use the amendment tables in a later GSTR-1 for the month the error is noticed.
Ignoring the time limit on amendments, or attributing interest to section 37(3).
Students focus on the procedure and forget that section 37(3) only gives the time limit, while interest sits in section 50.
Fix: State the cut-off: earlier of the due date of the September return following the financial year, or the actual date of furnishing the annual return. Then say interest on short paid tax is under section 50.

Worked examples

Example 1

Mohan Traders is a QRMP filer. For the quarter July to September, its B2B supplies are ₹30,00,000 in July, ₹60,00,000 in August and ₹45,00,000 in September. It wants to use IFF as much as possible. How much B2B value can be uploaded through IFF in each month? State the due dates for IFF, quarterly GSTR-1 and the July tax payment.

Show the solution

Mohan is a QRMP filer, so IFF is available for the first two months, July and August. It is not available for September.
July: B2B supplies are ₹30,00,000. This is within the ₹50,00,000 cap, so the full amount can be uploaded.
August: B2B supplies are ₹60,00,000. The cap is ₹50,00,000, so only ₹50,00,000 can go through IFF. The remaining ₹10,00,000 is reported in the quarterly GSTR-1.
September: no IFF. The ₹45,00,000 is reported in the quarterly GSTR-1.
Due dates: IFF for July by 13 August and for August by 13 September. Quarterly GSTR-1 by 13 October. July is the first month of the quarter, so its tax is paid by 25 August through PMT-06.

Answer: IFF: ₹30,00,000 for July and ₹50,00,000 for August; nothing for September. The balance ₹10,00,000 of August and all of September go in the quarterly GSTR-1 due on 13 October. July tax is payable by 25 August.

Example 2

A registered supplier in Maharashtra, a monthly filer, made these supplies in a month: (a) ₹4,00,000 to a registered dealer in Maharashtra; (b) ₹3,00,000 to an unregistered person in Gujarat; (c) ₹1,50,000 to an unregistered person in Gujarat; (d) ₹2,00,000 to an unregistered person in Maharashtra; (e) exports with payment of tax. Show where each is reported in GSTR-1 and the due date.

Show the solution

(a) Buyer is registered, so this is a B2B supply. Report invoice-wise.
(b) Buyer is unregistered, supply is inter-state (Maharashtra to Gujarat), and invoice value ₹3,00,000 is above ₹2,50,000. This is B2C large. Report invoice-wise.
(c) Unregistered buyer, inter-state, but ₹1,50,000 is not above ₹2,50,000. This is B2C small. Consolidate state-wise and rate-wise.
(d) Unregistered buyer, intra-state. This is B2C small regardless of value. Consolidate rate-wise.
(e) Exports are reported in the exports table, invoice-wise.
The supplier is a monthly filer, so GSTR-1 is due on the 11th of the following month. Under Rule 59(6), GSTR-1 cannot be furnished if the GSTR-3B for the immediately preceding tax period has not been furnished. The question gives no such default, so assume the condition is met.

Answer: (a) B2B invoice-wise; (b) B2C large invoice-wise; (c) and (d) B2C small consolidated; (e) exports table invoice-wise. Due date: 11th of the next month.

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.

Practice questions from Returns

GSTR-1: Details of Outward Supplies in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

GSTR-1: Details of Outward Supplies: frequently asked questions

What is the due date of GSTR-1?

For monthly filers it is the 11th of the next month. For QRMP filers it is the 13th of the month following the quarter. Dates can be extended by notification, so always follow the facts given in the question.

What is the QRMP scheme in GST?

QRMP lets a registered person with aggregate turnover up to ₹5 crore in the preceding financial year file returns quarterly and pay tax monthly. It covers GSTR-1 and GSTR-3B. Tax for the first two months of the quarter is paid by the 25th of the next month using 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.

What is IFF in GST?

The Invoice Furnishing Facility lets a QRMP filer upload B2B invoices in the first two months of a quarter, by the 13th of the next month. The limit is ₹50 lakh per month. It helps buyers claim input tax credit without waiting for the quarter end.

How do you correct a mistake in GSTR-1 after filing?

You cannot revise a filed GSTR-1. You report the correction in the amendment tables of a later GSTR-1, in the month the error is noticed, within the section 37(3) time limit. If tax was short paid, interest is levied under section 50, not under section 37(3).

Which supplies are shown invoice-wise in GSTR-1?

B2B supplies, B2C large supplies (inter-state to unregistered persons, invoice above ₹2,50,000), exports and SEZ supplies are shown invoice-wise. Other B2C supplies are shown as consolidated state-wise and rate-wise totals.