Bank statement reconciliation gaps: causes and first checks

Written by the team behind Slipnudge, an unbuilt product idea. We are not accountants. This is general process guidance, not accounting, tax or legal advice. Check anything important with the official source or a professional adviser.

When a bank reconciliation does not agree, the difference is rarely a single mystery. It is usually a handful of known patterns. This guide lists them with the first thing to check for each.

Start with the basics

The opening balance in the books equals the closing balance of the previous reconciliation.
The statement dates run on without a gap: last date of one statement is followed by the first date of the next.
Every account is included: current, savings, credit cards, and any payment platform account the client uses.
The statement balance you are reconciling to is the closing balance for the period end, not a printed "available" balance.
Currency is correct for foreign currency accounts.

Gap types and first checks

Pattern	Likely cause	First check
Bank line with no document	Receipt not supplied	See the guide on missing receipts at month end.
Document with no bank line	Paid in the next period, paid by another account, or not paid	Check the next statement and any other account or card.
Amount differs slightly	Fees, currency conversion, tips, rounding	Compare the document to the bank line. Look for a separate fee line nearby.
One bank line, many documents	Batch or combined payment	Ask for the remittance advice or the payment breakdown.
Many bank lines, one document	Part payments or instalments	Add the lines and compare to the document total.
Same amount twice	Duplicate payment, or duplicate entry in the books	Compare dates and references. Check whether an import ran twice.
Money in with no sales document	Customer paid early, refund, loan, capital introduced, transfer	Ask the client what the receipt was for, with the date and amount.
Card or platform payouts	Payout is net of fees and refunds, and may bundle several days	Use the platform's payout report to split the payout into its parts.
Transfers between own accounts	Two lines that should cancel out	Check both sides are recorded, in the same period, to a transfer account.
Refund or chargeback	Reverses an earlier payment	Link it to the original line and its document.
Difference equals one known amount	One item missing, entered twice or entered with the wrong sign	Search the books and the statement for that exact amount, and for half of it.
Difference equals a round number	Possible typing error or a missing line	Look for a transposed figure, such as 540 entered as 450.

A working order

Confirm opening balances and statement continuity.
Match the obvious lines first, by amount and date.
List the lines left over on each side.
Look for pairs that explain each other: batches, part payments, fees.
Look for the exact difference amount and for half of it.
Send the remaining items to the client in one list.
Record anything left unresolved, with the reason, before closing.

A query list to send to the client

Subject: [Client name]: [Month] bank queries

Hi [Name],

We have matched everything on the [account] statement except the
lines below. For each, please tell us what it was for, and send the
document if there is one.

Date | Money in/out | Amount | Shown on statement as
[dd Mon] | out | [amount] | [payee text]
[dd Mon] | in | [amount] | [payee text]

Please reply by [date].

Thanks,
[Your name]

Before you mark it done

The reconciled balance agrees to the statement closing balance.
Each unresolved item is on a query list with an owner and a date.
Any adjustments made to force agreement are recorded with the reason.
The statement itself is saved with the file.

We are considering a tool for this problem and keep an interest list for firms that would want one: see the Slipnudge home page.