How to reconcile a bank statement (and why it's the check that matters)

Reconciliation is the least glamorous step in bookkeeping and the only one that proves your numbers are actually right. Extraction tools can read a statement; reconciliation is what tells you they read it correctly. If you only run one check at month-end, run this one.

What reconciliation actually proves

A reconciled statement satisfies one equation: the opening balance, plus every transaction in the period, equals the closing balance printed on the statement. If that holds, no transaction was dropped, duplicated, or mis-signed. If it doesn't, something is wrong and the difference tells you roughly where to look.

Opening balance + Σ transactions = closing balance. If it balances, nothing went missing.

The three-line check

• Line 1 — Opening balance: does it match last period's closing balance?
• Line 2 — Movement: add up every debit and credit for the period.
• Line 3 — Closing balance: opening + movement should equal the statement's closing figure.

When line 3 doesn't match, the size of the gap is a clue. A gap equal to one transaction usually means a row was missed or entered twice. A gap that is exactly double a transaction means a debit was recorded as a credit. Round numbers often point to a manual typo.

Why it matters more with PDFs

Bank feeds are already structured, so errors are rare. PDF statements — scanned copies, old periods, small banks — are where transcription mistakes creep in, whether a human is typing or a model is extracting. That's exactly where an automatic reconciliation check earns its keep: it flags the suspect rows instead of letting a silent error reach the ledger.

Let the tool do the arithmetic

ScanStatement runs this reconciliation automatically on every conversion. Upload a statement PDF and the result carries a live badge: reconciled, or flagged with the exact difference so you can fix the row before exporting to Excel. The check is the point — verifiable data is what turns an extraction into books you can trust.