Monthly Bookkeeping Checklist for Small Businesses
Most compliance problems are bookkeeping problems that were left alone for a few months. GST credit lapses, TDS defaults, mismatched turnover and rushed audits all trace back to books that were closed late. This is the monthly routine that prevents them, in the order the deadlines actually arrive.
Why it matters
Books Kept Monthly Cost Less Than Books Kept Annually
Reconstructing a year in September takes longer, costs more and finds problems too late to fix.
Credit has a shelf life
Input tax credit for a year must be claimed by 30 November of the next year. Books closed in December find it gone.
Advance tax needs real numbers
Instalments fall due in June, September, December and March. Without current books, you're guessing, and shortfalls carry interest.
Mismatches get flagged automatically
GST turnover, income-tax turnover and e-way bill data are compared by system. Monthly reconciliation is what keeps them aligned.
Audits get expensive when rushed
A tax audit on books closed in September costs more in time and in disallowances than one on books closed monthly.
Week one: close the previous month
- Record every sales invoice, in serial order, with no gaps. Account for cancelled invoices rather than deleting them.
- Enter all purchase bills, including small cash purchases. Tag each supplier's GST status, which is what clause 44 of the tax audit report needs later.
- Record credit and debit notes in the month they're issued, not when the customer eventually deducts them.
- Reconcile every bank account to the statement. Clear old unpresented cheques rather than carrying them forward indefinitely.
- Reconcile cash in hand to the physical balance. A negative cash balance in the books is one of the first things an officer looks for.
- Deposit TDS by the 7th for the previous month's deductions.
- Check e-invoices and e-way bills were generated where required, and that they tie to your sales register.
Tagging each supplier as registered regular, registered composition, unregistered or exempt takes a few minutes when you create the ledger, and saves days of work at tax audit time. Do it once, at vendor creation.
Week two: returns and credit
File GSTR-1 by the 11th
Review it before filing, because GSTR-3B is now built from it and cannot be edited. Check B2B GSTINs, exports and credit notes carefully.
Review the Invoice Management System between the 12th and 14th
Accept, reject or keep pending. Anything untouched is treated as accepted when GSTR-2B is generated.
Reconcile GSTR-2B against your purchase register
List invoices in your books but not in 2B, and chase those suppliers the same week. Note anything in 2B that isn't yours.
File GSTR-3B and pay by the 20th
Confirm reverse charge on goods transport, legal fees and imports, and keep blocked credit out rather than claiming and reversing it.
Week three: money and people
Payroll
- Process salaries and record them in the month they relate to
- Deposit PF and ESI by the due date, since late employee contributions are permanently disallowed
- Deduct TDS on salary based on each employee's declared regime and investments
- Keep attendance and leave records with the payroll working
Receivables and payables
- Review debtor ageing and follow up on overdue accounts
- Check creditor ageing for invoices approaching 180 days, which forces a credit reversal
- Identify micro and small suppliers and track the 45-day payment rule
- Update your cash flow forecast for the next quarter
The MSME point deserves emphasis. Payments to micro and small suppliers beyond the permitted period are deductible only in the year of payment, so a bill unpaid on 31 March moves that expense into the following year. Running a monthly check against your Udyam-registered vendor list is far easier than untangling it at audit.
Quarterly tasks
| Task | When |
|---|---|
| Advance tax instalment | 15 June, 15 September, 15 December, 15 March |
| TDS and TCS quarterly statements | 31 July, 31 October, 31 January, 31 May |
| Issue TDS certificates to payees | Within 15 days of the statement due date |
| Check the TRACES default report | After each quarterly statement is processed |
| Review stock and physically verify a sample | Quarterly, monthly if you have a bank limit |
| Compare books turnover with GST returns | End of each quarter |
Year-end preparation, starting in January
- Physical stock count on 31 March, with a signed sheet showing quantities, rates and the valuation basis.
- Confirmations from major debtors, creditors and lenders, requested in February so they arrive in time.
- Fixed asset register updated with additions, their invoice dates and put-to-use dates, since assets used under 180 days get half depreciation.
- Provisions and prepaid expenses recorded, with TDS considered on year-end provisions.
- Clear the suspense and unclassified ledgers. Anything still sitting there in March will be asked about.
- File a fresh LUT before 31 March if you export, since it must be renewed each financial year.
- Reset your invoice series on 1 April, as GST requires a fresh series each financial year.
Habits that cause trouble
Mixing personal and business money
Personal expenses through the business account are disallowed, and they make every reconciliation harder. Draw a salary or drawings instead.
Large cash transactions
Cash payments above ₹10,000 to one person in a day are disallowed, and receipts of ₹2 lakh or more attract a separate penalty equal to the amount.
Filing returns without reconciling
Filing GSTR-3B from a rough figure and fixing it later no longer works, because the outward supply tables are locked to GSTR-1.
No stock records
Quantitative details are required in the tax audit report, and a bank limit makes them mandatory monthly. Reconstructing them is guesswork.
No backup of accounting data
Keep a backup off the office premises. Books and records generally need to be preserved for several years, and a failed hard disk is not an accepted explanation.
Saving everything for the auditor
Handing over a year of unentered bills in September guarantees a rushed audit, higher fees and disallowances that monthly work would have avoided.
This guide is general information on Indian tax and corporate law as it stood on 11 September 2026, and is not advice for any particular case. Rules, due dates and forms change, and how they apply depends on your facts. Please confirm the current position before acting, or speak to a qualified professional.
Who this applies to
Where the Monthly Routine Pays Off Most
Every business benefits, but these feel it most.
Manufacturers
Stock movement, job work and capital goods credit need month-by-month records that cannot be reconstructed later.
Businesses with a bank limit
Monthly stock statements are due to the bank anyway, so the books have to be current regardless.
Employers
PF and ESI deposited late are permanently disallowed, which makes payroll the least forgiving part of the month.
Exporters
Refund claims depend on returns, shipping bills and bank realisation matching, which only holds if entries are current.
Frequently asked questions
Answers to Your Bookkeeping Questions
How often should a small business close its books?
Monthly. GST returns, TDS deposits and the GSTR-2B reconciliation all run on a monthly cycle, so the books have to be current anyway. Closing quarterly or annually means credit lapses and mismatches are found too late to correct.
Do I need accounting software, or is a spreadsheet enough?
A spreadsheet can work for a very small business with few transactions, but GST-compliant software saves considerable time on invoice series, GSTR-2B reconciliation, vendor GST tagging and stock records. If you have a bank limit or a tax audit, software is effectively necessary.
How long do I need to keep my books and records?
Several years, and the exact period differs between the income-tax, GST and company law requirements, so keep to the longest that applies to you. Because GST notices can arrive two or three years after a year closes, keep the working papers behind your returns and reconciliations as well as the books themselves.
What happens if I deposit PF late?
Employees' contributions deposited after the due date under the PF law are not deductible at all, even if you pay before filing your return. The default is also reported in clause 20(b) of the tax audit report, so it is visible whether or not anyone asks.
Can I pay suppliers in cash?
Payments above ₹10,000 to one person in a day are disallowed as business expenditure, with a higher limit of ₹35,000 for transporters. Receipts of ₹2 lakh or more from one person in a day or for a single transaction attract a penalty equal to the amount received, so both sides of cash dealing need care.
Books Behind? Let's Get Them Current.
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C M Patel & Company, Chartered Accountants
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