Due dates, checklists and guides
GST and income tax dates for the rest of FY 2026-27, the documents to keep ready, and short guides to this year’s changes.
Due-date calendar
Passed dates are marked. Ask on WhatsApp for a reminder before the dates that apply to you.
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20thEvery month
GST
GSTR-3B for the previous month
Monthly GST filers. Quarterly (QRMP) filers have a different date.
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21Oct 2026
Income tax
Tax audit report for AY 2026-27
Businesses and professionals who need a tax audit. Extended from 30 September by CBDT Circular 07/2026.
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21Nov 2026
Income tax
Income tax return for audit cases, AY 2026-27
Taxpayers whose accounts are audited. Extended from 31 October by CBDT Circular 07/2026.
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15Dec 2026
Income tax
Advance tax, third instalment
By this date, 75% of the estimated tax for FY 2026-27 should be paid.
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31Dec 2026
GST
GSTR-9 and GSTR-9C for FY 2025-26
GSTR-9 is compulsory above ₹2 crore turnover and GSTR-9C above ₹5 crore.
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15Mar 2027
Income tax
Advance tax, final instalment
By this date, 100% of the estimated tax for FY 2026-27 should be paid.
Dates checked on 17 October 2026. Confirm them on the GST portal and the income tax e-filing portal.
Document checklists
Pick your business type.
Individual or proprietor
- PAN and Aadhaar
- Bank statements for the year
- Form 16 or salary slips, if salaried
- Sales invoices and purchase bills
- Rent agreement or electricity bill for the business premises
- Last year’s ITR acknowledgement
Partnership or LLP
- Partnership deed or LLP agreement
- PAN of the firm
- PAN and Aadhaar of each partner
- Bank statements for the year
- Sales and purchase registers
- Last year’s returns and financial statements
Private limited company
- Certificate of incorporation, MOA and AOA
- Company PAN and TAN
- PAN, Aadhaar and DIN of each director
- Bank statements for the year
- Sales, purchase and expense records
- Last year’s financial statements
Only the people working on your file can open these documents.
Guides
Short notes on this season’s dates and changes.
October 2026GSTR-9 and GSTR-9C for FY 2025-26Who must file the annual return by 31 December 2026, and what to check first.
GSTR-9 is the annual return that totals a year of GSTR-1 and GSTR-3B filings. For FY 2025-26 it is compulsory when aggregate turnover is above ₹2 crore, and GSTR-9C, the reconciliation statement, is required above ₹5 crore. Both are due by 31 December 2026.
Start by matching three figures for the year: sales in your books, sales reported in GSTR-1, and tax paid through GSTR-3B. If the books show more sales than the returns, the extra tax is paid with interest.
October 2026The Income-tax Act, 2025 and your returnsThe new Act applies from 1 April 2026. Your return for FY 2025-26 still follows the 1961 Act.
The Income-tax Act, 2025 replaced the 1961 Act from 1 April 2026. Income earned in FY 2025-26, which you report in the return for AY 2026-27, is still handled under the 1961 Act.
For FY 2026-27, advance tax runs under the new Act on the same instalment pattern: 75% of the estimated tax by 15 December 2026 and the full amount by 15 March 2027. Section numbers change under the new Act, so expect new references in notices and letters about FY 2026-27.
October 2026A month with no sales still needs a GST returnNo sales this month? GSTR-3B is still due by the 20th.
A registered business files GSTR-3B for every period, including months with no sales or purchases. A nil return takes a few minutes to file, but a late one attracts a late fee of ₹20 a day, capped per return.
If you expect a quiet season, say so in advance and the nil returns can go in on time.
October 2026Advance tax: the December instalmentWhat is due by 15 December 2026, and what happens if it is short.
Advance tax is income tax paid during the year instead of in one amount at the end. By 15 December 2026, 75% of the estimated tax for FY 2026-27 should be paid, and the full amount by 15 March 2027.
A short or late instalment adds interest, generally 1% a month on the shortfall. Salaried people whose tax is fully covered by TDS usually have nothing to pay.
Want a reminder before each date?
Send us a WhatsApp message with the returns you file and we will remind you ahead of each one.