BOOKKEEPING GUIDE · UPDATED AUGUST 2026
The monthly bookkeeping checklist that makes year-end boring
Every filing a Singapore company makes — GST F5, ECI, the corporate tax return, the Annual Return — is assembled from the same monthly ledger. Close the books properly each month and those deadlines become paperwork; skip months and each one becomes an investigation. Here is the close we run, in order.
STEP ZERO · CAPTURE
Before the close: is everything in the books?
The close can only reconcile what was recorded. These four capture habits, kept up during the month, are what make the month-end itself quick.
Sales invoices — issued and recorded
Every invoice raised during the month is in the books, numbered sequentially, with the right GST treatment if you are registered. Gaps in the invoice sequence are the first thing a reviewer, auditor or IRAS query will ask about.
Supplier bills and recurring charges
Bills received — including the easy-to-miss ones: software subscriptions charged to a card, foreign invoices, rent, insurance instalments. Recording them in the month they relate to is what makes your profit figure mean something.
Receipts and staff expense claims
Source documents attached to the transaction, not sitting in a drawer or a WhatsApp thread. IRAS requires records that can explain every business transaction, kept for at least 5 years from the relevant Year of Assessment — digital copies are fine.
Cash and director-paid expenses
Anything paid personally by a director or in cash needs a claim or a director's loan entry this month. Left too long, these become the unexplained balances that stall year-end and inflate the amount owing to or from directors.
THE CLOSE
The month-end close, in order.
Run the same seven steps in the same week every month. The order matters: reconciliation first, because every later step assumes the cash figures are real.
Reconcile every bank and card account
Match the accounting ledger to the actual statement balance for each bank account, credit card and payment gateway (Stripe, PayNow aggregators, marketplace payouts). Unreconciled differences are errors by definition — find them now, while the transaction is a week old, not in eleven months.
Clear the clearing accounts
Gateway payouts arrive net of fees; marketplaces settle in batches. The clearing or undeposited-funds account should return to zero (or a known in-transit amount) at month end. A growing clearing balance means revenue or fees are being missed.
Review aged receivables and chase
Run the aged receivables report, confirm what is genuinely still collectable, and chase anything past terms. The monthly close is also when unpaid invoices stop being an accounting fact and start being a cash-flow decision.
Post payroll and confirm CPF went out
Salaries, employer and employee CPF, SDL and any CPF board levies posted to the right accounts — and the CPF submission actually paid by the 14th of the following month. Payroll is the one monthly deadline with a statutory clock attached.
Check GST coding while it is fresh
If you are GST-registered, scan the month's transactions for coding errors — standard-rated vs zero-rated sales, blocked input tax claims, reverse-charge items. Fixing a mis-coded month now is minutes; unpicking a quarter at F5 time is hours, and errors past the concession thresholds mean a GST F7.
Post the boring adjustments
Depreciation, prepayment releases, accruals for bills not yet received, hire-purchase splits. Small entries, but they are the difference between management accounts that track reality and a profit figure that jumps around with billing timing.
Produce and actually read the management accounts
Profit and loss against last month and budget, balance sheet scanned for accounts that look wrong (negative cash, growing suspense, receivables older than 90 days), and a cash position you believe. Ten minutes of reading is the payoff for the whole close.
WHY IT PAYS OFF
Every statutory filing draws on this close.
GST F5 — one month after each quarter
Each GST return is due within one month of the end of the accounting period, payment included. Three clean monthly closes make the F5 an assembly job rather than an investigation.
The GST F5 cycle, box by boxECI — three months after FYE
Estimated Chargeable Income is due within 3 months of the financial year end unless the company qualifies for the waiver. A current set of books is what makes the estimate defensible.
ECI filing and the waiver testAnnual Return — seven months after FYE
The ACRA Annual Return, with financial statements in XBRL where required, is due within 7 months of the financial year end for a non-listed company. Every month you close on time shortens the year-end close that feeds it.
Calculate your AR deadlineCorporate tax — 30 November
Form C-S or Form C is due by 30 November each year, built on a tax computation that starts from your accounting profit. Clean books all year mean the adjustments are the only real work left.
The 30 November timelineWHERE BOOKS GO WRONG
The six mistakes we untangle most often.
Reconciling only at year end
A December reconciliation of twelve months of transactions is archaeology. Errors compound: a duplicated invoice in March distorts every management report after it, and by the time it surfaces the trail is cold.
A growing suspense or miscellaneous account
Suspense is where transactions go to be forgotten. Anything parked there should be resolved within the month it was parked — a suspense balance that only grows is unrecorded profit, unrecorded cost, or both.
Mixing personal and company spending
Director's personal expenses through the company account create tax adjustments, potential benefits-in-kind and a director's account that needs explaining. One card for the company, one for the person, and the problem mostly disappears.
Booking revenue when cash arrives
Singapore financial statements are prepared on an accrual basis — revenue when earned, expenses when incurred. Cash-basis books understate receivables and payables and make the GST and tax numbers wrong, not just the timing.
No source document behind the entry
An entry without an invoice or receipt behind it fails the record-keeping test even when the amount is right. IRAS expects records kept for at least 5 years from the relevant YA; storage is cheap, reconstructing 2024 in 2029 is not.
Treating the close as optional in quiet months
Skipping a slow month breaks the streak that makes every later filing easy. The close should be boring and fixed — same steps, same week of the month, whether the month was big or small.
Common questions.
How long should monthly bookkeeping take for a small company?
For an SME with tidy processes — bank feeds connected, receipts captured digitally, a fixed close routine — a monthly close is typically a few hours, not days. The time balloons when months are skipped: reconstructing a quarter routinely takes longer than three closes done on time would have.
What records does IRAS require my company to keep?
Source documents (invoices, receipts, vouchers), accounting records and schedules, and bank statements — enough to explain every transaction relating to income, expenses and purchases. Records must be kept for at least 5 years from the relevant Year of Assessment, and electronic copies are acceptable. GST-registered businesses have parallel record requirements for their GST declarations.
Do I need accounting software, or are spreadsheets enough?
There is no legal requirement to use software — IRAS encourages software on its Accounting Software Register Plus (ASR+) but does not mandate it. In practice, spreadsheets stop being workable once transaction volume grows, GST registration arrives or more than one person touches the books. Bank feeds and audit trails are what software buys you.
Is monthly bookkeeping compulsory in Singapore?
No law prescribes a monthly cycle — what the law requires is proper, explainable records (Companies Act and Income Tax Act) and filings that arrive on deadline. Monthly is simply the cadence at which staying compliant is cheapest: GST runs quarterly, CPF monthly, and annual filings all draw on the same ledger.
What are management accounts and do I really need them monthly?
Management accounts are the internal monthly pack — profit and loss, balance sheet, and usually cash and receivables views — produced from the closed ledger. Nobody files them, but they are the point of the exercise: they are how you notice margin slippage, unpaid invoices and cash problems while they are still small.
When should an SME hand bookkeeping to an accountant?
Common triggers: GST registration (quarterly deadlines with penalties), the first employee (payroll and CPF each month), transaction volume that makes the close eat founder evenings, or a bank or investor asking for management accounts. Outsourced monthly bookkeeping in Singapore is normally priced as a fixed monthly fee tied to transaction volume.
Official sources
Record-keeping requirements and filing deadlines are as published by IRAS, the CPF Board and ACRA, checked on 25 August 2026.
This guide provides general information, not professional advice. Record-keeping obligations and filing deadlines depend on the company’s circumstances, GST registration status and financial year end, and IRAS, CPF Board and ACRA requirements change from time to time.
WRITTEN BY
Jacqueline May
Principal Accountant · Chartered Accountant (Singapore), ISCA member
Jacqueline is a Chartered Accountant (Singapore) and ISCA member, and the Principal Accountant at Synergy Accounting, a Singapore practice established in 2013. She works on corporate tax, GST and ACRA compliance for small and medium businesses — the filings, deadlines and judgement calls most owners would rather hand over. These guides are written from what she sees in practice.