Key takeaways
What this article covers, in order:
- Why bother closing every month?
- The month-end close checklist
- Steps 1 to 4: get the bank right first
- Steps 5 to 8: debtors and creditors
- Step 9: accruals and prepayments, kept simple
- Steps 10 to 12: tidy up, read, lock
A month-end close is the short routine that turns a month of bank lines, invoices and bills into numbers you can trust. Done well, it takes a few hours, catches mistakes while they're still fresh, and means your P&L for the month actually means something. Below is the month end checklist we'd hand any UK owner or bookkeeper, in the order that saves the most rework.
Why bother closing every month?
Picture Tom. He runs a two-person joinery business in Bristol and does his books "when there's time", which in practice means every four months or so. On 3 Oct 2026 he finally sits down and finds a £2,140 payment from a customer he can't place, three supplier invoices he's sure he paid twice, and a van insurance renewal that went out in Jun 2026 and was never recorded.
None of that is a disaster. But each one costs ten minutes of detective work that would have taken thirty seconds at the time. That's the whole case for a monthly close: the evidence is still in your head, your inbox and your bank app.
There's a second reason. If you only look at the books quarterly, you only find out you're short of cash quarterly. A monthly close gives you twelve chances a year to spot trouble instead of four.
The month-end close checklist
Work through it roughly in this order. The order matters, because later steps rely on earlier ones being right.
| # | Task | What "done" looks like | Typical time |
|---|---|---|---|
| 1 | Bring all bank and card transactions in | Every account shows activity up to the last day of the month | 5 min |
| 2 | Clear the review list | No uncategorised or unconfirmed lines left for the month | 20 to 60 min |
| 3 | Reconcile every bank account | Book balance agrees with the statement closing balance | 15 to 30 min per account |
| 4 | Reconcile credit cards | Card balance agrees with the card statement | 10 to 20 min per card |
| 5 | Check sales invoices are all raised | Every job finished this month has an invoice dated this month | 10 min |
| 6 | Review aged debtors | Overdue invoices chased, disputes noted | 10 min |
| 7 | Enter and check supplier bills | All bills received this month are in, with the right dates | 15 min |
| 8 | Review aged creditors | Nothing paid twice, nothing overdue by accident | 10 min |
| 9 | Post accruals and prepayments (if you use them) | Big costs sit in the month they relate to | 10 min |
| 10 | Clear the suspense account | Suspense balance is zero, or every item has a note | 10 min |
| 11 | Read the P&L and balance sheet | Nothing looks odd against last month | 15 min |
| 12 | Lock the period | Nobody can quietly change last month's numbers | 1 min |
You won't need every row every month. A sole trader with no stock and no staff might do steps 1 to 6 and 11 and call it a night. That's fine. The point is to have a list so you don't rely on memory.
Steps 1 to 4: get the bank right first
Everything else hangs off the bank. If your bank lines are incomplete or miscategorised, your debtors, your creditors and your profit will all be wrong in ways that are hard to trace.
So start by making sure every account is up to date. If you connect your bank through Open Banking, the feed should already have the month's transactions. If an account isn't connected, download a CSV statement from online banking and import it.
Then work the review list. Confirm the categories that are right, change the ones that aren't. Watch for the usual troublemakers:
- Transfers between your own accounts. Money moving from current account to savings isn't income or an expense. Make sure both sides are recorded as a transfer.
- Customer receipts. Match them to the invoice they pay rather than posting them straight to sales, or your debtors will never go down.
- Supplier payments. Same idea in reverse: match them to the bill.
- Anything personal that went through the business account. Flag it so it can be posted to drawings or the director's loan account, whichever applies.
Now reconcile. Take the closing balance on the bank statement for the last day of the month and check it agrees with the balance in your books once you account for anything that hasn't cleared yet. If it doesn't agree, stop and find the difference before moving on. A gap carried forward only gets harder to find.
Credit cards follow the same routine. People skip them because the card statement date rarely lines up with month end, but an unreconciled card is where duplicate subscriptions and forgotten refunds hide.
Steps 5 to 8: debtors and creditors
Once the bank is right, your sales and purchase ledgers can be trusted.
Sales first. Go through your diary, job sheets or project board for the month. Did every finished job get invoiced? Tom found two kitchen fittings from Aug 2026 that he'd forgotten to bill, worth £1,860 between them. That's money he'd have written off by accident.
Then aged debtors. This report shows who owes you what and how late they are. Anything over 30 days deserves a polite chase. Anything you believe will never be paid is a conversation with your accountant about writing it off, not something to quietly delete.
Bills next. Enter every supplier invoice received in the month, dated with the invoice date rather than the day you got round to typing it in. Then look at aged creditors. Two entries for the same amount from the same supplier a few days apart is usually one bill entered twice, not two deliveries.
Step 9: accruals and prepayments, kept simple
If you keep your books on an accruals basis, costs belong in the month they relate to, not the month you pay them. Most small businesses only need to bother with the big ones.
Say Tom's workshop electricity is billed quarterly. He knows from past bills that Sep 2026 usage is around £180, but the bill won't arrive until Nov 2026. To keep the Sep 2026 profit honest, his bookkeeper posts an accrual:
| Account | Debit | Credit |
|---|---|---|
| Electricity (expense) | £180.00 | |
| Accruals (liability) | £180.00 | |
| Total | £180.00 | £180.00 |
Next month the entry is reversed, and when the real bill arrives it's posted as normal. The net effect is that each month carries roughly its own share of the cost.
If that feels like overkill for your size of business, it might be. Plenty of sole traders run perfectly good books without a single accrual. Ask your accountant which, if any, are worth posting for you.
Steps 10 to 12: tidy up, read, lock
Suspense. Anything you couldn't identify earlier often gets parked in a suspense account. Fine for a day or two, not fine at month end. Clear every item, or at least write a note against it saying what you're waiting for.
Read the reports. Open the P&L for the month and compare it with the month before. You're not doing analysis here, just a sense check. Did fuel triple? Did sales drop to zero in a week you know was busy? Odd numbers usually mean a categorisation slip, not a business crisis.
Then the balance sheet. Does the bank balance shown agree with your reconciliation? Is the suspense line zero? Are debtors roughly what you'd expect from the aged report? These three checks catch most errors.
Lock it. Once you're happy, lock the period so nobody can post into it by mistake. If something genuinely needs changing later, you reopen it on purpose and the change gets recorded.
How HelloBooks helps
HelloBooks pulls transactions in when you connect your bank through Open Banking (most UK banks and cards), or you can import a CSV statement. Transactions land in a review list where you confirm or change categories, and on Pro the AI suggests categories for you.
The bank reconciliation screen lines your statement up against your ledger with an AI match suggestion on each line, a confidence score and the reason it picked that match, so you only work through the exceptions. You can unmatch in one click if a match is wrong. When you're done it produces a reconciliation report (opening balance, cleared items, outstanding items, closing balance) that exports as PDF or CSV, and the reconciled period can be locked, with any reopening logged.
Aged debtors and creditors, the P&L, balance sheet and cash flow report are all on the Free plan. You can see what's in each plan on the UK pricing page, or read more about automated bookkeeping.
FAQs
When should I do my month-end close?
Within the first week of the following month is a sensible target. Leave it a few days so late card transactions and supplier invoices have arrived, but not so long that you've forgotten what anything was.
What's the difference between month-end close and reconciliation?
Reconciliation is one step inside the close. It proves your bank balance is right. The close covers everything else too: invoices, bills, accruals, the suspense account and a read of the reports.
Should I lock the month after closing?
Yes. Locking stops accidental edits to numbers you've already checked. If you need to correct something, reopen the period deliberately so there's a record of the change.
What if the bank won't reconcile at month end?
Don't move on. Check for transactions dated in the wrong month, duplicates from the feed, and amounts keyed with digits swapped. A difference divisible by 9 is a classic sign of a transposition.
Put the dates in your calendar for the next three months and see how the second close compares with the first. It gets quicker.
Start free, no card needed. Try HelloBooks Free
