Guide for bookkeepers

How to reconcile a bank account with Claude (and get it to 0.00)

Pasting two CSVs into a chat and asking "do these match?" gives you a confident answer that is often wrong. The fix is to make Claude follow the same procedure you would: normalise, match in strict passes, classify the leftovers, then prove the balance.

1. Export the right two files

• Bank side: the statement period as CSV from the bank or card portal.
• Books side: QuickBooks Online "Transaction Detail by Account" filtered to the account and period, or Xero "Account Transactions". Export to CSV.
• Write down the statement ending balance and the ledger balance on the last day.

2. Normalise before matching

Most mismatches Claude reports are sign errors. Banks often show withdrawals as positive numbers in a "Debit" column; ledgers show them as negatives. Tell Claude to convert both to one signed amount from the account's point of view (money in positive, money out negative), and to report row counts and totals for each file before it matches anything. Ambiguous dates like 03/04 should be asked about, not assumed.

3. Match in passes, strictest first

1. Same amount, same date, same reference or check number.
2. Same amount within 3 days.
3. Same amount within 10 days and a shared payee word.
4. One bank deposit equal to several ledger receipts (batched card deposits, undeposited funds).
5. Several bank lines equal to one ledger entry (Stripe, Square or PayPal payouts net of fees).

Each row is used once, and nothing is forced to match just to make the totals work. Anything uncertain goes into a "needs review" list.

4. Classify what is left

• In the bank, not the books: fees, interest, auto-pays, transfers.
• In the books, not the bank: outstanding checks and deposits in transit. Flag anything over 60 days.
• Amount mismatches: if the difference divides evenly by 9, it is probably a transposition.
• Possible duplicates: same amount and payee within a week in the ledger.

5. Prove it

Statement ending balance
+ deposits in transit
- outstanding checks and payments
= adjusted bank balance

Ledger ending balance
+ unrecorded bank credits
- unrecorded bank debits
= adjusted book balance

Difference: 0.00

If the difference is not zero, ask Claude to rank likely causes by how much of the gap each one explains, rather than "fixing" it.

Written by Teton Labs with AI assistance. This is a workflow guide, not accounting, tax or audit advice. Always review results before posting entries, and remove full account numbers from files you share with any AI tool.