Year-end bookkeeping checklist for 2026: November, December and January, with dates

Year-end 2026 key dates

Year-end is three months of work, not one week in January. These are the dates the plan below is built around. The 2027 dates already account for weekends. The March and April dates apply the IRS's standing rules to 2027 (partnership and S corporation returns are due the 15th day of the third month after the year ends, individual returns April 15), and both fall on weekdays.

Your accountant needs finished books well before March 15 or April 15. Plan to hand them over in February.

November: W-9s, the 1099 list and payroll codes

Start with contractors, because it is the job with the longest lead time. Run purchases by vendor from January 1 to today and mark everyone you paid for services by check, ACH, bank transfer or cash. Payments by credit card or through a payment network are reported by the processor on Form 1099-K, so leave them out of your 1099-NEC totals.

For payments made in 2026, a contractor gets a 1099-NEC once you have paid them $2,000 or more, up from $600 for 2025 (who counts under the new threshold). Say a plumber paid one subcontractor $1,850 by check and another $2,400: only the second needs a form. Ask for a W-9 now from anyone at or near the line, while they still answer email. The W-9 gives you the legal name, tax ID and entity type the form needs.

Then decide how you will file. FIRE, the system many businesses and their software used to e-file 1099s, stops accepting returns at 3 p.m. Eastern on November 19, 2026. Forms 1099 for tax year 2026 go through IRIS, whose free Taxpayer Portal takes up to 100 returns at a time, and the IRS tells current FIRE users to complete an IRIS application for a Transmitter Control Code (how IRIS filing works). Once you file 10 or more information returns in total, you have to e-file.

Employers have one more November job. The 2026 Form W-2 has new fields: box 12 code TT for qualified overtime, code TP for cash tips reported to you, code TA for employer contributions to an employee's or a dependent's Trump account, and box 14b for the Treasury tipped occupation code. Confirm now that payroll can report qualified overtime and tips separately (what goes in each code). Rebuilding those figures from timesheets in late January is slow, and a wrong W-2 means a corrected one.

December: reconcile, clean up receivables, count, decide on purchases

Reconcile through November 30. Do every bank, credit card, loan and payment processor account, so December is the only month left in January. A reconciliation ties your books to the statement's ending balance, line by line. In BooksGPT you tick the lines each statement cleared and finish at a $0.00 difference, with a report kept for every statement (bank reconciliation).

Clear out receivables. Run accounts receivable aging as of December 31 and chase anything over 90 days. Write off what you will not collect, so the balance sheet stops showing money you will never see. On the accrual basis, an invoice you already counted as income can be a bad debt deduction. On the cash basis it was never income, so there is nothing to deduct.

Count inventory. Count on December 31, or as close to it as you can. Ending inventory sets cost of goods sold: every $1,000 of stock you miss in the count adds $1,000 to this year's cost of goods sold.

Decide on equipment before, not after, December 31. For tax years beginning in 2026, Section 179 lets you expense up to $2,560,000 of equipment, reduced once you place more than $4,090,000 of it in service. Bonus depreciation is 100% and permanent for property acquired after January 19, 2025. Either way the deduction starts when the asset is placed in service, so a machine ordered in December and installed in January is a 2027 item. A purchase you do not need is still a cost: at a 24% bracket, a $20,000 machine cuts income tax by about $4,800 and cash by $20,000.

Set retirement contributions. Salary deferrals into a 401(k) for 2026 generally must be elected by December 31 (an owner can deposit them later, up to the return deadline). The 2026 deferral limit is $24,500 before catch-up contributions. A SEP can wait: you can set it up and fund it as late as the return's due date, including extensions.

Split the mileage log at July 1. The business rate was 72.5 cents a mile through June 30, 2026 and 76 cents from July 1 (the 2026 mileage rates). Say you drove 5,200 business miles in the first half and 4,800 in the second: 5,200 x $0.725 = $3,770, plus 4,800 x $0.76 = $3,648, for $7,418. One rate all year would give $7,250 and leave $168 off the deduction.

Worked example: does December cash tie to the bank?

This is the check your accountant runs first. Say a roofing company's December 31 bank statement ends at $18,420.55. Checks written December 29 and 30, for $1,200.00 and $340.00, have not cleared. A $2,150.00 customer deposit made December 31 posts on January 2.

If the balance sheet shows $19,105.55, you have a $75.00 difference to find before anything goes out. Look for a $75.00 transaction entered twice, entered in the wrong month, or keyed with the wrong amount. Do not post an adjustment to make it go away: an unexplained plug is exactly what an accountant sends back.

January: the estimate and the forms

Reconcile December as soon as the statements arrive, then lock the year. Pay the fourth 2026 estimate by January 15, 2027. You can skip that payment only if you file your 2026 return and pay the full balance by February 1, 2027 (how estimated payments work).

By February 1, 2027, send Forms W-2 to employees and the Social Security Administration, and Forms 1099-NEC to contractors and the IRS. Both copies are due the same day.

The year-end mistake that costs the most

Waiting until January to ask for W-9s. The contractor you paid by check in March has moved on, the form goes out late or not at all, and the penalties for forms due in 2027 run from $60 per form fixed within 30 days up to $340 per form. A separate penalty can apply to the copy the contractor never received. Ten forms missed entirely can cost 10 x $340 = $3,400 for the IRS copies, and the same again for the contractor copies.

What to hand your accountant

• The bank, card and loan statements for every account, with a reconciliation report through December 31 for each.
• Profit and loss, balance sheet, trial balance and general ledger for 2026, on the basis your return uses (cash or accrual).
• Accounts receivable and payable aging as of December 31.
• Invoices for equipment bought in 2026, with the date each item went into use.
• Loan statements showing December 31 balances and interest paid.
• Year-end payroll reports and your Forms W-2 and W-3.
• The contractor list with 2026 totals and W-9s.
• The inventory count and the mileage log.
• A short list of open questions.

BooksGPT runs these reports on cash or accrual, with the transactions behind each number, exports them to Excel, CSV or PDF, and lets you close the period through December 31 so nothing changes after you send them (reports). The free accountant handoff checklist is a printable version of this list.

What to do next, in order

1. This week, run the vendor list and request W-9s from everyone at or near $2,000.
2. Before November 19, move off FIRE if you used it, and start the IRIS application.
3. By mid-December, reconcile every account through November 30 and confirm payroll can report overtime and tips.
4. On December 31, count inventory, confirm new equipment is in use, and have 401(k) deferrals elected.
5. In the first week of January, reconcile December, write off bad receivables and close the period.
6. On or before January 15, pay the fourth estimate.
7. By February 1, send W-2s and 1099-NECs, then send your accountant the package.