The trader's tax calendar

What this lesson explains and who it is for

This lesson shows how to keep tax records running all year, so filing season is just copying prepared numbers. It is for anyone trading in their own account, using more than one platform, or holding part of their capital in crypto — and who does not want to reconstruct last year’s history in March. There are no rates or specific dates here: those change with the regulations, so you confirm them in an official source. What you will find is the mechanism: what to record, how often to review it, and how to measure whether the data is complete before there is no time left to fix it.

The tax calendar is a tool, not a return. It does not replace filing, or a conversation with an adviser when the case is complex. It settles one question: when the documents are due, will you have what you need to fill them in?

Two logs, not one

Most traders keep a single log and are surprised it cannot answer “do I have everything”. The event log says what happened. The activity log proves it.

The event log itself — its columns, event types, and cost-matching method — is described in the lesson crypto taxes. Here we deal with the second log, because it decides whether the first can be used at all. A log with no support in source documents is only a note, and a note does not document a loss.

The activity log: a format that survives

The activity log is kept rarely but systematically. Its value is not its volume but that a year later it answers questions without logging into the platforms. The columns that earn their place:

Three of these columns do all the work. The period covered lets you detect a gap without opening a file. The verification result is the outcome of a comparison, not the word “checked”. Where the copy lives answers the question that always comes up at the worst moment.

Keep the activity log in the same file as the event log, on a separate tab. The same spreadsheet also serves your trading metrics — see journaling and metrics and journal and review.

The quarterly routine: a five-step protocol

This procedure is repeatable and requires no decisions. Run it in the same order every time so the result compares with the previous quarter.

1. Export the history from each platform separately. Name the file with the export date and platform so alphabetical sorting shows the chronology.
2. Add a row to the activity log. Date, platform, period covered by the export, path to the file.
3. Calculate coverage. coverage = months with an export / months in which you traded. A result of one means no gaps. Below one means a gap you must name before the window of access to the data closes.
4. Reconcile. consistency = events in the export / events in the log. A deviation from one in either direction has two causes: a missing entry in the log, or a missing part of the export. Both must be pointed at, not “explained away”.
5. Record the result and the date. Put the next review date straight into your calendar. A review with no successor turns into a series of one-off efforts.

Deviations in reconciliation are normal on a first pass. Their value is that they show up while something can still be fixed.

The year’s schedule: what you do and what evidence remains

The quarterly rhythm is not arbitrary. Four reviews a year (illustrative figure) follow because a quarter is the longest interval at which an error from early in the year can still be caught before it reaches the annual summary.

Deadlines: check them at the source, not from memory

Four things to keep in mind rather than know by heart:

• Withholding tax on dividends. The payer — the broker or the issuer — collects it if your account supports it. That does not release you from keeping the log, because it covers only some events. Selling securities involves no advance payment: you settle the 19% yourself in PIT-38, so this case always goes into the log. Status as of September 2026 — confirm at the source.
• The annual return in PIT-38 for the previous year. Check the current deadline for a year at podatki.gov.pl, not in a note from last season.
• Crypto events during the year. They do not arise only when you withdraw to a bank account, so the calendar covers the whole year — the mechanics are in the lesson crypto taxes in Poland.
• Withholding tax on foreign dividends. The procedure and deadlines depend on the treaty between the countries and the issuer’s jurisdiction. The word “dividend” alone is not enough — check the rules for that market; the term itself is explained under dividend.

A practical rule: at every quarterly review, note in the activity log where you checked the deadlines and when. The date of the check is part of the documentation, because regulations and official announcements change.

You measure completeness with three numbers

There is no way to assess a log by feel. Three numbers are enough to know where you stand.

The third measure is the one most often skipped, and it protects you from surprises. An operation you cannot classify will not disappear from your return just because it is missing from the spreadsheet.

When the calendar says “do not trade”

1. You have no export for a period longer than the last quarter, and you plan further transactions in the same account. You are adding events to a set you cannot document anyway.
2. Your log has no column for an event flag. Without it you do not know how many operations create a taxable event, so you do not know how big the problem is.
3. You plan to close an account or switch platforms, and the history has not been exported yet. Once an account is closed, access to the history is sometimes impossible, and the gap becomes permanent.
4. You assume the platform’s dashboard will be available “sometime, when it is needed”. The dashboard is an operational tool, not a tax archive, and its availability is often limited in time.

None of these conditions is a verdict on your whole operation. Each means one thing: close the documentation first, then add new positions.

Common mistakes

• A log kept “from March”. With no earlier data there is nothing to document losses with.
• Treating commissions as insignificant. They lower the tax base, and every transaction generates them. The full cost of a round turn appears under round-trip cost.
• Exporting once a year. By then the data is already needed, and there is no time to correct mistakes.
• “The broker will settle everything.” With several accounts and crypto, you compile the summary yourself. The broker’s formalities are described in the lesson choosing a broker, and the tax background of investing in taxes on investments.
• No copies of the source files. An export that stayed on the platform’s drive is not your evidence.
• Relying on memory for deadlines. Last year’s deadline is not information, it is a memory.

A measurable exercise

Run the full cycle once, on one platform, and record the result with the date.

1. Export the history for the last twelve months and save the file with the date in its name.
2. Fill in the first row of the activity log in every column.
3. Calculate coverage and consistency using the formulas from this lesson and record both results.
4. List every operation you cannot classify unambiguously and count them.
5. Set four quarterly review dates in your calendar (illustrative figure) and a reminder to verify the current deadlines before the season.

The result you are after is not “I am organised” but three numbers and a list of items to confirm. Those tell you whether your filing will be a formality or a reconstruction.

Common questions

Do I need a separate log for taxes and for my trading journal?

No. One file with two tabs is enough: events serve your metrics and your taxes, while activities track exports, copies, and reviews. One entry, double the value.

When should I export from an exchange?

Quarterly, each platform separately. That cadence protects you from losing access to the data and leaves time to correct mistakes before the data is needed for the return.

Why measure coverage and consistency if I only file once a year?

Because those two numbers are the only early signal that the log is incomplete. Without them, feedback arrives only after you file — as a correction, interest, and questions you must answer with documents. Measuring moves detection of a gap from March to the quarter in which it can still be closed.

What should I do if I have no exports and filing season is approaching?

Start with whatever the platforms still offer and download it immediately, oldest periods first. Then calculate coverage so you know how much of the data is missing, and write the gaps down explicitly. Going forward, set up a quarterly routine, because without documents part of your losses stays non-deductible.