How do you prepare tax working notes for an accountant?

Who does what?

The accountant files. I prepare. That division is written at the top of the working notes so that neither of us forgets it. My job is to make the preparation complete and honest enough that the accountant spends their time on judgement rather than on reconstruction.

What goes in the income section?

Everything, reconciled to two sources. For 2025 the income was three fixed-fee engagements and eleven day-rate bookings, and each invoice is matched to the invoice ledger and to the bank statements. One invoice was issued in December and paid in January; under the cash basis it sits in the 2026 year, and the notes say so rather than leaving the accountant to find the gap.

Reconciling to both sources is the point. The ledger says what was billed; the bank says what arrived. Where they disagree, the note explains why.

What goes in the costs section?

What is claimed?

The costs I believe are allowable, each with its receipt in the folder kept with the notes: home office at the simplified rate, the professional membership renewal, the certification exam fee and study materials, laptop depreciation in its second year, mileage from the log rather than fuel receipts, and professional indemnity insurance.

What is not claimed?

This section matters as much as the first. Not claimed: the coworking day passes without receipts, and the personal share of the phone plan. Writing down what was left out tells the accountant that the omission was a decision, not an oversight, and saves a round of questions.

What stays open?

Two questions, left for the person qualified to answer them. Whether the certification course fee is treated as training that maintains existing skills. How the deferred January payment should be shown.

I have an opinion on both and it is not in the notes, because my opinion is not the thing being paid for. The notes state the facts, the question and nothing else. The accountant answers; the answer goes into the notes with their name on it; and next year's preparation starts from a settled position rather than from the same open question.

When is it due?

The return is due at the end of the following January. The accountant needs the reconciled ledger four weeks earlier. That date, not the filing deadline, is the one in my calendar, because the filing deadline is the accountant's and the preparation deadline is mine.

Working backwards from it, the reconciliation happens as the year closes, the receipt folder is checked against the costs list, and the notes are sent in time for the questions to be asked and answered before anyone is in a hurry.

Where do the notes live afterwards?

With the receipt folder, and with a copy of the filed return once it is accepted. The working notes are preparation, and the filed return is the record. Keeping both together means that next year's notes can start from what was actually filed rather than from what I intended to file.

The same discipline applies to everything on my desk. A note is evidence of what was prepared or said. The document it leads to, the filed return, the issued invoice, the signed letter, is the record. The two are kept together and never confused.

What does this have to do with operations?

More than it looks. A tax return is a flow with a constraint, and the constraint is the accountant's time in January. Everything I do in the notes is subordinating my work to that constraint: arriving early, arriving reconciled, arriving with the decisions already made and the open questions named. It is the same method as a depot review, applied to a folder of receipts.

Q&A

The questions people ask most about preparing for an accountant are answered below.

Last updated 1 October 2026.