Methodology

How the tax rules are sourced and kept current

Every calculation is based on the actual Polish tax statutes (ustawa o PIT) and the official figures published by ZUS and the Ministry of Finance each year — contribution base caps, relief limits, and bracket thresholds.

These figures are versioned per tax year in the calculator's code. A new tax year is never offered until its official figures are confirmed and the full internal test suite has been re-run against them — we'd rather be a year behind than quietly wrong.

How broker statement imports are verified

Each supported broker's import is built from that broker's documented export format. Every parsed transaction is shown to you for review before anything is saved — nothing is accepted automatically.

Cost-basis matching uses FIFO (the method Polish law requires) and foreign-currency amounts are converted using the official NBP average exchange rate for the relevant date — both shown per row so you can check the math yourself, not just trust a final number.

Accuracy cross-checks

The PIT-38 line-by-line reference view was built and checked directly against real, filed PIT-38 forms to confirm the section numbers, labels, and figures line up with the actual government form — not just a plausible-looking approximation.

How your data is handled

This calculator asks for real financial information, so what happens to it matters as much as what it calculates. Three things are true today, not just promised for later:

• Deleting your account removes every tax year and every figure permanently, in one action — see Account settings.
• Analytics never sees your figures. We record which broker you imported and whether it succeeded, nothing about amounts or holdings.
• You can export everything you've entered as structured JSON at any time, from Account settings.

Known limitations

Not every broker's import format has been confirmed against a real exported file yet — some are still built purely from documented formats, though the same review-before-saving step applies regardless.

Some less common reliefs and the PIT-ZG foreign-income attachment aren't modeled yet. Always treat the result as a well-informed estimate, and double-check anything unusual against an accountant or the official forms.

The short version

This is an estimate tool for your own planning, not official filing software and not tax advice — see our Terms of Service and Privacy Policy for the full picture.