Behind on your books with tax season coming: what to do, by date

By Diane Jones, Certified QuickBooks ProAdvisor, 30+ years of bookkeeping
Updated October 2026

If your 2026 books aren’t caught up, the calendar decides more than you’d think. Some dates can move and some can’t, and the work that matters most depends on how far behind you are. Here’s how I’d plan it.

The dates that matter

The 1099s are the first hard wall. They’re built from a full year of vendor payments, so if 2026 isn’t entered, they can’t be right. My 1099 guide for 2026 covers what changed this year, including the new $2,000 threshold.

An extension buys time to file, not to pay

This is the part people miss. An extension gives you six more months to file the return. It doesn’t give you more time to pay. The IRS says Form 4868 "doesn’t extend the time to pay taxes," and Form 7004 "does not extend the time to pay any tax due." So by March 15 or April 15, your CPA still needs numbers solid enough to estimate what you owe, and those numbers come from the books.

That’s why a partial catch-up still helps. Even if the books won’t be finished by April, getting the income side right and the bank accounts reconciled through December gives your CPA something real to estimate from.

What I’d do first, by how far behind you are

A few months behind

Catch up now, oldest month first, and you’ll be current by December 31. Then year-end is an ordinary close instead of a project. My catch-up guide walks through how I work statement by statement.

Most of 2026 behind

Get the statements for every account, every month, before anything else. Then work in this order: enter the vendor payments so the 1099s are right by February 1, reconcile every account through December, and hand your CPA the year in time for March 15 or April 15. If that’s too tight, the extension covers the filing and the reconciled income side covers the payment estimate.

Two years or more

That usually means returns that haven’t been filed, and that’s more common than people think. The books come first, oldest year your CPA needs first, then the next. Your CPA or an enrolled agent handles the returns and any conversation with the IRS. The IRS says to keep records "indefinitely if you do not file a return," so old statements and receipts are worth digging out. Nobody gets a lecture from me about how it got this way.

What to gather this month

• Bank and credit card statements for every account, for every month that’s missing
• Loan statements, so principal and interest get split right
• Payroll reports from your payroll provider, if you have employees
• W-9s for anyone you paid for work this year
• Last year’s return, so the starting balances match what your CPA filed

Statements matter more than receipts. Most of a year can be rebuilt from statements alone, and the receipts fill in the details.

I’m a bookkeeper, not a tax preparer or attorney. For tax and legal questions, confirm the details with your CPA. I keep the books that make their job easier.