Every deadline your business needs to hit in September 2026 — explained simply, with what each filing involves and exactly what it costs to miss it.

September is the most compliance-intensive month of the financial year for Indian businesses. Three major obligations converge in a single 30-day window: GST return filings for August, the second installment of advance tax for FY 2026-27, and the monthly TDS deposit cycle. Most crucial is furnishing of Audit Report under section 44AB (of Income-tax Act, 1961 as applicable for FY 2025-2026) on or before due date i.e. 30th September 2026. A single day delay may cost a heavy penalty which may extend to 1.50 Lakh.

For businesses with turnover above ₹5 crore, GSTR-3B is due on 20 September. The advance tax second instalment — 45% of estimated annual liability, cumulative — is due on 15 September. The TDS deposit for August deductions is due on 7 September. If your business falls under all three, you have a significant cash flow obligation in a single fortnight.

This blog gives you every deadline for September 2026, explains what each involves, and gives you the penalty calculation for any you miss — so you can prioritize correctly and avoid paying a rupee more than you owe.

All September 2026 Compliance Deadlines at a Glance

This is your complete compliance calendar for September 2026. Dates shaded in blue are GST deadlines; those in green are income tax and TDS deadlines.

TDS Compliance in September 2026

TDS Deposit — 7 September 2026

Any TDS deducted from payments made in August 2026 must be deposited with the government by 7 September 2026. This applies to salary TDS (deducted monthly from employee salaries), TDS on contractor payments, professional fees, rent, interest, commission, and any other payment where TDS is applicable under the Income Tax Act, 2025.

Governing law: Since all August 2026 payments occur after 1 April 2026, TDS is now governed by Section 393 of the Income Tax Act, 2025 (not Sections 194C, 194J, 194H etc. of the old Act). When depositing TDS, ensure your challan quotes the correct new section reference. Portal validation may fail if old Act section numbers are used for post-March 2026 transactions.

Advance Tax: The 15 September Deadline Explained

The 15 September deadline is the second of four advance tax installments for FY 2026-27. It is also the most misunderstood — because the percentage required is cumulative, not just for the quarter.

What ‘cumulative 45%’ means in practice: If your estimated annual tax liability is ₹3 lakh, you must have paid a total of ₹1,35,000 by 15 September — including whatever you paid on 15 June. If you paid ₹30,000 in June (10% — below the required 15%), you need to pay at least ₹1,05,000 in September to reach the 45% cumulative threshold. The shortfall from June also attracts interest.

Who is exempt from advance tax:

• Senior citizens (above 60 years) with no business or professional income — fully exempt from advance tax
• Presumptive taxation taxpayers under Section 44AD and 44ADA (small businesses and professionals with turnover/receipts below the prescribed limits) — can pay 100% of advance tax as a single instalment by 15 March 2027
• Salaried individuals whose entire tax liability is covered by employer TDS — no advance tax required

GST Filing Deadlines in September 2026

GSTR-1: Outward Supply Return — 11 September 2026

Monthly GST filers must report all B2B and B2C invoices issued in August 2026 by 11 September. With GSTR-3B hard-locked since July 2025, GSTR-1 accuracy is more important than ever — errors cannot be corrected directly in GSTR-3B and must go through GSTR-1A before GSTR-3B is filed.

• Critical for September specifically: Any FY 2025-26 invoice that has not yet been reported or was reported with errors must be amended in September’s GSTR-1 (Table 9A). The November 2025 amendment cut-off has passed — September is the last practical window to capture FY 2025-26 output corrections before year-end.
• QRMP filers: September is the last month of Q2 (July–September). Your quarterly GSTR-1 for Q2 is not due until 13 October 2026. However, if you have B2B buyers whose ITC depends on seeing your August invoices in their September GSTR-2B, use the Invoice Furnishing Facility (IFF) before 13 September to upload those invoices for the month.

GSTR-3B: Summary Return + Tax Payment — 20 September 2026

GSTR-3B for August 2026 is due 20 September for monthly filers. This is simultaneously the most important deadline this month and the one with the most cash flow impact — particularly for businesses that also owe advance tax by 15 September.

• September-specific cash flow alert: If you owe both advance tax (15 Sep) and GSTR-3B tax payment (20 Sep), plan your liquidity carefully. Both are cash outflows within 5 days of each other. For a business with ₹50 lakh monthly GST turnover, the GSTR-3B net tax payment alone can be ₹3–8 lakh. Add the advance tax instalment and the combined cash requirement in one fortnight is material.

PMT-06: Monthly GST Payment for QRMP Taxpayers — 25 September 2026

QRMP taxpayers file GST returns quarterly but pay tax monthly. The August 2026 tax payment via Form PMT-06 is due by 25 September. The amount can be calculated using either the Fixed Sum Method (35% of previous quarter’s GSTR-3B tax) or the Self-Assessment Method (based on actual August ITC and liability). If August was a high-revenue month compared to last quarter, the Fixed Sum Method may underpay — use the Self-Assessment Method for accuracy.

Tax Audit Report Deadline — 30 September 2026

Businesses and professionals whose books are required to be audited under Section 44AB must have their Chartered Accountant sign and upload the tax audit report (Form 3CD/3CA/3CB) by 30 September 2026. The ITR filing deadline for audit cases is 31 October 2026 — which is directly dependent on the audit report being completed first.

Who this applies to:

Businesses with turnover above ₹1 crore (₹10 crore if cash transactions are below 5%), and professionals with gross receipts above ₹50 lakh (₹75 lakh under presumptive scheme). Directors of private limited companies and partners of auditable firms also need to ensure the entity-level audit is complete before their personal ITR deadline.

What Each Missed Deadline Costs You: September Edition

September’s deadlines are more expensive to miss than most months — because three of them carry compounding consequences.

Planning Your September Cash Flow: The Fortnight That Matters

For any SME owner juggling GST, TDS, and advance tax simultaneously, September requires deliberate cash flow planning. Here is the sequence of outflows and what to prepare:

September Has Three Deadlines in One Fortnight. Let’s Make Sure You Hit All of Them.

Related Reading

→ July 2026 GST & TDS Due Dates: Don’t Miss These Compliance Deadlines

→ Advance Tax September 15 Deadline: How to Calculate & Pay Correctly

→ Quarterly Review: How to Reconcile GST & Books Before Q2 Ends

→ 10 Signs Your Growing Business Needs a Virtual CFO Right Now

The post September 2026 GST, TDS & Advance Tax Calendar: What You Need to Know for Simple Filing first appeared on CPC Services Pvt. Ltd..

Looking for GST due dates April 2026, TDS return filing deadlines, or a complete April 2026 tax compliance calendar?

The first month of the financial year is not just about planning — it’s about execution. April sets the compliance foundation for FY 2026–27, and even small delays can trigger penalties, disrupt cash flow, and create year-long complications.

The New Income Tax Act 2025 is set to reshape taxation from 1 April 2026.
If you’re a business owner, professional, or taxpayer, understanding these changes is essential.
Here’s a simple breakdown of what changes in FY 2026–27 and what you should do next.

Key Tax Deadlines – April 2026

• GSTR-1 (March 2026) → 11 April 2026
  
• GSTR-3B (March 2026) → 20 April 2026
  
• QRMP GSTR-3B → 22nd / 24th April 2026
  
• CMP-08 (Composition Dealers) → 18 April 2026
  
• TDS/TCS  Deposit (March deductions) → 07th April for TCS and 30th April for TDS
  
• TDS/TCS Return (Q4 FY 2025–26) → 15th May for TCS and 31st May for TDS

Why April Is a Critical Compliance Month

April is a high-risk, high-impact period because:

• Financial year transition (FY 2025–26 → FY 2026–27)
  
• Books are being finalized
  
• New compliance cycles begin
  
• TDS credits impact employees & vendors
  
• GST filings continue without interruption

GST Due Dates – April 2026

GST compliance continues seamlessly into the new financial year. Missing even one return can affect your entire tax chain, which is why many businesses rely on GST compliance services.

Why GST Compliance in April Matters

• Ensures accurate ITC (Input Tax Credit) flow
  
• Prevents GST portal restrictions
  
• Maintains vendor trust & reconciliation accuracy
  
• Avoids late fees (₹50/day or ₹20/day for NIL returns)

TDS Return Filing – April 2026

April is crucial for TDS compliance, especially for closing the previous financial year. Businesses often streamline this with direct tax compliance support.

Key TDS Deadlines

Delays in TDS return filing April 2026 can directly affect employee trust and vendor relationships.

Other Important Compliance Deadlines in April 2026

Beyond GST and TDS, businesses must also track:

1. PF & ESIC Contributions

• March contributions must be deposited in April
  
• Non-compliance leads to penalties and interest and may impact HR & payroll processes

2. Professional Tax (State-wise)

• Monthly or quarterly filings depending on jurisdiction

3. Advance Tax Planning

• Businesses should reassess projections for FY 2026–27 with proper financial advisory

4. Book Closure & Reconciliation

April is the ideal time for:

• GST reconciliation
  
• Vendor ledger review
  
• TDS mismatch correction
  
• Financial statement preparation supported by accounting services

Consequences of Missing April Deadlines

Ignoring April 2026 compliance deadlines can result in:

• GST late fees up to ₹50/day
  
• Interest up to 18% per annum
  
• TDS late filing fees under Section 234E
  
• ITC blockage and working capital issues
  
• Increased scrutiny from tax authorities often requiring audit & assurance services

A single missed filing can trigger compliance stress for the entire year.

Common April Compliance Mistakes

Even experienced teams make errors during transition:

• Treating April as a “buffer month”
  
• Delaying March TDS deposit
  
• Incorrect GST carry-forward balances
  
• Ignoring reconciliation mismatches
  
• Missing updated compliance rules

These small mistakes often lead to larger financial and audit complications later.

How to Build a Strong April 2026 Compliance Strategy

Step 1: Create a Compliance Calendar

Track:

• GST due dates April 2026
  
• TDS filing deadlines
  
• Monthly statutory obligations

Step 2: Reconcile Before Filing

• Match purchase & sales data
  
• Verify ITC claims
  
• Cross-check TDS deductions

Step 3: Assign Clear Responsibility

Define:

• Who prepares returns
  
• Who reviews
  
• Who approves submission

Step 4: Avoid Last-Day Filing

Delays can occur due to:

• GST portal issues
  
• DSC token errors
  
• Banking delays

Who Should Read This?

This guide is especially useful for:

• Business owners & entrepreneurs
  
• SMEs & startups
  
• Finance teams & accountants
  
• Freelancers & consultants

Across multiple industries served where compliance accuracy is critical.

Why Early Compliance Improves Business Credibility

Timely tax compliance helps businesses:

• Build vendor and client trust
  
• Improve creditworthiness
  
• Ensure smooth audits
  
• Reduce legal and financial risks
  
• Maintain strong financial discipline

April 2026 Compliance Checklist

• File GSTR-1 (March 2026)
• File GSTR-3B
• Deposit March TDS by 7 April
• File Q4 TDS return by 30 April
• Deposit PF & ESIC contributions
• Reconcile GST and TDS records
• Plan compliance calendar for FY 2026–27

What happens if GST is not filed on time?

Late filing leads to:

• Late fees
  
• Interest liability
  
• ITC restrictions
  
• Compliance notices

Why is April important for tax compliance?

April marks:

• Financial year transition
  
• Start of new compliance cycle
  
• Closure of previous year obligations

Is TDS deposit mandatory by 7 April?

Yes, TDS deducted in March must be deposited by 7 April 2026, failing which interest applies.

Start FY 2026–27 the Right Way

April is not just about deadlines – it’s about setting a standard for the year ahead.

Businesses that proactively manage GST due dates April 2026, complete TDS return filing on time, and track all tax deadlines April 2026 India avoid unnecessary penalties, reduce stress, and operate with confidence.

The first month defines the financial discipline of the remaining eleven.

Need Help with April 2026 GST & TDS Compliance?

Avoid penalties, notices, and last-minute stress.

CPC Services Pvt. Ltd. helps businesses with:

• GST return filing & reconciliation
  
• TDS deposit & return filing
  
• Monthly compliance management
  
• End-to-end tax planning

You can also contact our team here to get started. Start FY 2026–27 with clarity, accuracy, and complete compliance.

The post New Income Tax Act 2025: What Changes You Must Know first appeared on CPC Services Pvt. Ltd..

Tax Changes from 1 April 2026: What You Must Know

India is entering a new era of income-tax compliance.

After governing direct taxation for over six decades, the Income-tax Act, 1961 will be repealed on 31 March 2026. From 1 April 2026, the New Income-tax Act, 2025 will come into force.

For taxpayers, businesses, employers, and deductors, this is not merely a legislative update — it is a decisive shift toward time-bound, technology-driven, and irreversible compliance.

What you don’t correct before 31 March 2026 may never be correctable again.

Why Is the Income-Tax Act, 1961 Being Replaced?

Over the years, the Income-tax Act, 1961 became increasingly complex due to:

• Dense statutory language
• Multiple provisos and explanations
• Conflicting interpretations
• Prolonged litigation
• Compliance uncertainty for businesses

To address these challenges, the government introduced the Income-tax Act, 2025, focusing on clarity, automation, and finality — areas where professional direct tax advisory services play a crucial role.

Key Objectives of the Income-Tax Act, 2025

• Simplified and clearer statutory language
• Reduced ambiguity and litigation
• Technology-driven processing and enforcement
• Strict timelines for compliance and corrections
• Improved ease of doing business

In short:
Flexibility under the old law is being replaced by discipline, automation, and finality—making structured tax and compliance services more important than ever.

Key Transition Dates You Must Remember

Although the new Act applies prospectively, past  corporate compliance under the old Act must still be corrected within permitted timelines.

Major Change: TDS Correction Time Limit Reduced

One of the most impactful changes under the Income-tax Act, 2025 relates to TDS correction statements.

Position Under Income-tax Act, 1961

Earlier, deductors could file TDS correction statements for up to 6 years from the end of the relevant financial year. This allowed correction of:

• PAN errors
• Challan mismatches
• Short or excess deductions
• Late filing issues
• Incorrect reporting

This flexibility benefited businesses managing large volumes of TDS transactions and accounting services.

Position Under Income-tax Act, 2025

The correction window is now reduced to just 2 years.

What This Means for Deductors

• Errors beyond 2 years cannot be corrected
• Old TDS defaults may become permanent
• Outstanding demands may never disappear
• Interest and late fees may continue indefinitely
• System-level restrictions may block corrections

This change directly impacts employers, HR & payroll deductors, and businesses making regular TDS payments.

TDS Correction Timeline: Old vs New

FY 2025–26 is the final clean-up year for legacy TDS issues.

Understanding Section 200A(3) Under the New Act

Section 200A(3) of the Income-tax Act, 2025 significantly strengthens automated enforcement.

Practical Impact on Deductors

• TDS statements processed entirely through the system
• Correction filings may be blocked after prescribed timelines
• No scope for post-deadline manual rectification

Automatic computation of:

• Late fees
• Interest
• Short deduction demands

Discretionary relief under the old regime is now replaced by system-controlled finality increasing the importance of expert advisory services.

Impact on Pending TDS and TCS Demands

Many businesses still have unresolved issues such as:

• Outstanding TDS defaults
• PAN mismatch intimations
• Short deduction notices
• TCS discrepancies
• Section 200A demands

If these are not resolved before 31 March 2026, they may:

• Continue indefinitely in the tax system
• Attract ongoing interest and late fees
• Create hurdles during assessments and audit processes
• Affect compliance ratings and future filings
• Delay refunds or approvals

31 March 2026: The Final Window for Legacy Corrections

The repeal of the Income-tax Act, 1961 also ends extended correction flexibility.

Before this date, deductors must:

• Review all historical TDS & TCS returns
• Identify pending defaults and mismatches
• File eligible correction statements
• Respond to outstanding notices promptly
• Preserve supporting documentation

Post-2026, the old 6-year correction rule will not apply.

Who Should Take Immediate Action?

This transition impacts:

• Corporates and LLPs
• SMEs and startups
• Employers with payroll TDS
• Professionals and consultants
• Businesses deducting TDS on rent, commission, interest, or professional fees

This includes growing entities and startups setting up compliance frameworks as well as industry-specific businesses listed under industries served.

Why Early Compliance Is the Safer Strategy

Businesses that act early can:

• Reduce interest and penalty exposure
• Avoid system-based correction blocks
• Improve long-term compliance history
• Ensure a smooth transition to the new tax regime
• minimize future disputes and litigation

This proactive approach also supports better financial and wealth planning.

Quick Compliance Action Plan for Deductors

How CPC Services Pvt. Ltd. Can Help You

CPC Services Pvt. Ltd. supports businesses with:

• Comprehensive review of historical TDS & TCS returns
• Identification and resolution of pending defaults
• Filing of correction statements within timelines
• Handling Section 200A intimations and demands
• Smooth transition advisory to the new tax regime
• Ongoing compliance monitoring

For personalised assistance, you can contact our team or explore our service plans and pricing.

Clean the Past Before Entering the New Tax Era

The repeal of the Income-tax Act, 1961 marks the end of flexibility and the beginning of finality.

With:

• Reduced correction timelines
• Stricter provisions like Section 200A(3)
• Limited scope for post-deadline relief

Proactive compliance is no longer optional — it is essential.

The post Important Changes in the New Income Tax Law first appeared on CPC Services Pvt. Ltd..