Compliance Calendar for CA Firms: Never Miss a Client Due Date

On 25 September 2025, five days before the tax audit report was due, the CBDT moved the date for assessment year 2025-26 from 30 September to 31 October 2025, citing floods and other disruptions and representations from CA bodies, as BDO summarised. On 29 October it moved again, to 10 November, and the return due date for audit cases went from 31 October to 10 December 2025, as LiveLaw reported. Two changes in five weeks, in the busiest season of the year.

Every firm that kept its due dates in a printed calendar, a WhatsApp forward or a column of hard-coded dates in Excel had to update them by hand, client by client. That is the problem this guide solves: how a CA firm builds a compliance calendar that never misses a client due date, even when the dates move. It is written for proprietor CAs and small to mid-sized firms, and draws on what Infoways sees when setting up task and reminder systems for practices. I am not a chartered accountant. Every date question goes to the official source, and I say which one.

What is a compliance calendar for a CA firm?

A CA firm’s compliance calendar is the list of every statutory due date the firm handles, linked to the clients each date applies to, with a task, an owner and a status for each client and period. It answers two questions every morning: what is due soon, and for which clients is it at risk.

Most firms already have the first half, a list of dates. What they are missing is the link to clients. A date on its own says “GST returns are due this week”. A calendar that works says “41 GST clients are due this week, 9 have not sent purchase data, and 3 of those belong to the partner who is on leave.” The rest of this guide builds that second version step by step.

1. The recurring due-date families, and where to confirm each

A CA firm’s calendar is built from seven recurring families: GST returns and payments, TDS and TCS, advance tax, income tax returns, tax audit reports, ROC and MCA annual filings, and PF and ESI. Each has its own cycle and an official place where the current dates are published.

I have deliberately not printed a full date list for 2026-27. The Income-tax Act 2025 came into force on 1 April 2026, with a single “tax year” and renumbered forms under the Income-tax Rules 2026, while work for 2025-26 and earlier still uses the old forms, as TaxGuru and ClearTax report. Copying last year’s date sheet into a year with a new Act is exactly how a firm ends up wrong. Use the table below to know what to track, then take each date from the official source.

Source: cycles from each department’s published scheme; QRMP structure from the GSTN FAQ on QRMP and IFF. Day-of-month dates deliberately left out; take them from the official site for the period you are working on.

A few verified details worth building in

• Under QRMP, taxpayers with aggregate turnover up to ₹5 crore can file GSTR-1 and GSTR-3B quarterly and pay monthly; the optional Invoice Furnishing Facility for a month expires after the 13th of the next month, and the monthly payment challan is due by the 25th of the next month, per the GSTN FAQ. Each client’s QRMP choice also has opt-in windows per quarter, listed in the portal FAQ. Your calendar needs a “filing frequency” field per GSTIN for this reason.
• From the July 2025 tax period, GSTR-3B liability auto-filled from GSTR-1 is locked, and corrections go through GSTR-1A before 3B is filed, per the GSTN advisory and ClearTax. So GSTR-1 is now a hard step before 3B, and your task needs both stages in order.
• AOC-4 is due within 30 days of the AGM and MGT-7 within 60 days, under Sections 137 and 92 of the Companies Act 2013, as TaxGuru sets out. These dates move with each client’s AGM, so they cannot sit on a fixed calendar at all; they have to be calculated from a date you record per client.

2. Why the calendar must be editable

Due dates in India change by notification, press release or circular, sometimes days before the deadline, so a firm’s calendar must store each date once, in a table someone is responsible for, with every client task pointing to it. When the date changes, one edit should move every task.

The tax audit example in the opening is not unusual. The first extension came by press release and Circular 14/2025, per BDO, and the second release said a formal notification would follow. That means a firm also needs to record why a date changed and on whose authority, because the team will act on the press release before the notification arrives.

When we build task systems for practices, the date table is the first thing we design, and it is usually the smallest. Each row holds the compliance, the period, the client category it applies to, the statutory date, the source link and the date it was last checked. Extensions are a new row version, not an overwrite, so you can still show a client later what the date was on the day you filed.

Source: Infoways’ experience setting up practice task systems; extension sequence as reported by BDO and LiveLaw.

3. Map every client to the compliances that apply

Client mapping means recording, for each client, the attributes that decide which compliances apply: registrations, filing frequency, constitution, audit status, AGM date and employee coverage. Tasks are then generated from those attributes rather than chosen by memory.

This is where most calendars fail quietly. A trader moves from monthly GST to QRMP, a proprietor crosses the audit threshold, a company changes its AGM date, and nobody updates the sheet. The calendar still looks complete; it is just wrong for those clients. So the map has to be reviewed at fixed points, at least at the start of each financial year and each GST quarter.

Source: Infoways practice-software setups; applicability rules belong to the respective Acts, so a partner signs off each client’s map.

See also: If you are deciding whether to buy practice software or build around your own workflow, read custom software vs off-the-shelf first.

4. Turn dates and clients into tasks with owners

A task is one client, one compliance and one period, with an owner, a stage and three dates: when to request documents, when to start preparation, and the statutory due date. Tasks should be created automatically when a period opens, not typed in by staff.

The statutory date is the last date, not the working date. In the firms we work with, the useful internal rule is that documents are requested well ahead of the due date and preparation starts on a fixed internal date, so review and partner sign-off have room. The exact gap is your call; what matters is that it is set once per compliance and applied to every client, instead of being decided task by task.

1. Awaiting documents: the client has been asked; the checklist shows what is missing.
2. In preparation: an article assistant or junior is working on it.
3. Under review: a manager has raised review points that must be cleared.
4. Partner approval: waiting for sign-off, with DSC availability checked.
5. Filed: the acknowledgement is attached to the task and visible to the client.

For GST, split the task into the GSTR-1 step and the GSTR-3B step, because of the liability lock from July 2025. For ROC, the task cannot open until the AGM date is recorded. These small rules are where a calendar stops being a list and starts preventing mistakes.

5. Send client reminders that actually get documents in

Client reminders work when they go out on a schedule tied to the task, list the specific documents still missing, give one way to send them, and stop as soon as the checklist is complete. Generic “your GST is due” messages get ignored.

What we see in practice is that the date is rarely the problem; the documents are. A good reminder says “We still need your March purchase register and the HDFC statement for March. Upload here.” A follow-up goes out a few days later only if they are still missing, and after a set number of reminders the task lands on the manager’s list for a call. WhatsApp Business is the channel most clients read; our guide to WhatsApp Business, AI and UPI covers templates and opt-in.

Keep promotional messages out of this channel. The ICAI Code of Ethics bars solicitation, so compliance reminders to existing clients should stay informational and specific to their work.

6. Track status and handle extensions in one place

A partner should be able to see, for any due date, how many clients are filed, in review, in preparation and still awaiting documents. When an extension comes, the date row changes, the affected tasks move, and clients who were chasing the old date get one short note.

Two habits help. First, review a “due in seven days” view every Monday, by stage; a large pile in “awaiting documents” five days out is the earliest warning you will get. Second, do not relax the internal dates when the statutory date moves. In the 2025 tax audit season the date moved twice; firms that kept their internal plan finished early, while those that reset everything to the new last date met the same crunch a few weeks later.

7. Spreadsheet or practice management software?

A well-built spreadsheet is enough for a proprietor with a few dozen clients. Once you have more clients, more staff or several partners, a practice management tool or your own system is safer, because the spreadsheet cannot send reminders, cannot move tasks automatically, and cannot show the client their status.

Source: Infoways’ experience; ICAI’s free cloud practice management software for members is described at bs.icai.org. Features vary by product and version, so test any tool with your own client list.

Start with what is free. ICAI offers its members a free practice management tool, and several Indian vendors sell subscriptions. For most small firms, one of these is the right answer. A custom system makes sense when you have several partners or branches, an outsourcing team with hundreds of bookkeeping clients, or a need to link the calendar to your own client portal, billing and accounting tools. That is the work we describe on our CA firm software page.

8. What to automate first

Automate the steps that are repetitive and rule-based: task creation each period, document requests and follow-ups, the weekly status view, DSC expiry alerts and the extension update. Keep judgement steps, such as applicability decisions and review, with people.

• Task creation: when a month or quarter opens, create tasks from the client map.
• Document chasing: reminders that list missing items and stop when complete.
• Status digest: a Monday summary to each partner by stage and due date.
• DSC expiry: alerts weeks before a client’s or partner’s certificate expires.
• Extension update: one date change, all tasks moved, affected clients listed.
• Fee invoice on filing: an invoice with a payment link when the acknowledgement is attached.

Our wider guide to AI and automation for small businesses covers where automation pays and where it creates new risks.

Where this advice breaks down

A system does not decide applicability. If a client’s map is wrong, the calendar will be confidently wrong, so the partner review of client attributes matters more than any feature. Software also cannot make a client send documents; at some point a person still has to call.

The new Income-tax Act adds a real transition risk for 2026-27: two sets of form names running side by side, and dates that firms are still learning. No calendar template, including any you buy, should be trusted without checking it against the Income Tax Department for the specific tax year. And very small practices may honestly be better off with a disciplined spreadsheet and the free ICAI tool than with a new system rolled out in a hurry. Never switch systems in July or September.

Compliance calendar setup checklist

The tax audit date moved twice in 2025. A firm with one editable date table changed two rows; a firm with dates scattered across sheets changed hundreds. Build the first kind.