How do I catch up on bookkeeping before my tax return is due?

What catch-up actually means

Catch-up bookkeeping is not sorting a year of transactions into categories. It is reconciling every missing month, for every account, to its statement. The books are caught up when the ending balance in the books for each account matches the statement for the last day of each month, and the year-end balances agree with what the bank, the card company and the lender say you have and owe. Anything less is a guess, and the guess goes onto your tax return.

What to gather

• Bank statements for every business account, every month, including accounts opened or closed during the year.
• Credit card statements, including any personal card used for business charges.
• Loan and line of credit statements, so each payment can be split between principal and interest.
• Merchant and payment-processor statements. They show gross sales, fees and refunds. The bank shows only the net deposit.
• Payroll reports from your payroll provider: the quarterly 941s, the state returns and the year-end W-2 summary.
• 1099s you issued and received. For payments made in 2026, a 1099-NEC is required for nonemployee pay of $2,000 or more. They are due February 1, 2027, because January 31 falls on a Sunday.
• Sales tax returns you filed during the year.
• Last year’s business return. Its balance sheet is the starting point for this year’s books.

The order of work

• Start from last year’s return. Opening balances have to match the prior-year balance sheet. If they do not, that gets fixed first.
• Reconcile one month at a time, oldest first. Each month’s ending balance is the next month’s starting balance, so skipping ahead only moves the errors.
• Book what the bank does not show. Payroll from the provider’s reports, loan interest, owner draws and contributions, and sales tax owed.
• Send one list of questions. Deposits to identify, charges to explain, receipts to find.
• Close the year and prepare the return. The return is only as good as the December balances.

How long it takes, and why the extension matters

The time depends on how many months and accounts are missing and how quickly statements and answers come back. Request every missing statement on day one. Older statements can take time to get from a bank or lender, and nothing can be reconciled without them.

Calendar-year S Corporation and Partnership returns are due March 15. For 2026 returns that is Monday, March 15, 2027. Form 7004, filed by that date, extends the deadline six months, to September 15, 2027. Individual returns are due April 15, and an extension moves them to October 15. In both cases the extension is more time to file, not more time to pay. Any tax owed is still due on the original date.

If you are more than a few months behind when January arrives, plan on the extension. A return rushed out on unreconciled books is how errors get filed, and fixing them later means an amended return.

A worked example: the late-filing penalty

S Corporations and Partnerships usually owe no federal income tax themselves, so owners assume a late return costs nothing. It does. The IRS charges a flat amount for each owner, for each month or part of a month the return is late, up to 12 months. For returns due in 2027 the amount is $260. For returns due in 2026 it was $255.

Alexander and one other shareholder own an S Corporation. The books stopped in March 2026. In February 2027 he calls with April through December missing on a checking account, a credit card and a merchant account: 27 statements to collect and reconcile.

A return filed July 2 is four months late, because March 16 to July 2 covers three full months and part of a fourth, and a partial month counts as a whole one. The same return, on extension, is on time. The penalty also has nothing to do with whether the books were hard to finish. The K-1s go out late too, which holds up both owners’ personal returns.

The IRS will sometimes remove this penalty under first-time penalty relief, if the business filed on time for the prior three years. That is a one-time pass, not a plan. See how penalty relief works.

How we price it

We quote catch-up up front, at a flat price per month of statements, before any work starts. Once the books are current, we move you to a monthly package, starting at $350 a month, so the next year closes on time. See what monthly bookkeeping includes, or what bookkeeping costs in Bergen County.

This guide is general information based on the law as of the date above, not advice for your situation. Tax rules change, and the right answer depends on your numbers.