One invoice starts the month's paperwork — after that: your revenue ledger (ewidencja przychodów) under ryczałt (flat-rate tax), the monthly tax advance worked out, and the annual JPK_EWP (yearly ryczałt filing) ready to send.
Sign up with your email — you could be invoicing within minutes.
Four things happen between issuing an invoice and closing the books for the month — here is what each one actually does.
You send each invoice to KSeF (Poland's e-invoicing system) yourself, and the UPO (official confirmation of receipt) comes back attached to the document. Auto-submit exists too — it stays off until you switch it on.
Your invoices build the revenue ledger automatically, sorted under the ryczałt rate you have set for that period.
The monthly tax advance comes out of that ledger as a running total for the year. It counts from revenue alone — ZUS (social security) contributions are not deducted, so treat it as your calculation base, not the final amount due.
Once the year wraps up, you pull the annual JPK_EWP together from that same ledger and file it with the tax office by 30 April — the UPO lands back with it.
The rate is not a choice: it follows from the PKWiU classification of the work you actually do, and services tied to software are named outright in the 12% provision. Where the scope sits on the border, only an individual tax ruling settles it — best worked out with an accountant. In Biurko you enter the settled rate with the date it takes effect, all nine statutory rates are available, and every month is settled at the rate in force in that month. The effective date is yours to set, so moving it back re-settles the closed months too.
New sales in a given period go out under a single rate. If your work mixes two rates — say 12% alongside 8.5% — splitting a single period between them is not something the app does for you.
VAT registers and the JPK_V7 work the same way — but only once you are registered for VAT (czynny podatnik VAT). Not registered? Those screens simply do not apply to you.
Ryczałt 12%, full ZUS with the health contribution, no business costs. The full calculator compares four taxation paths and an employment contract at the same cost to the company.
15,811 zł
left every month
189,733 zł over a year
An informational estimate, not tax advice.
Open the full B2B calculatorCharging a client outside Poland brings its own paperwork — currency, exchange rates, language, VAT wording. Here is what actually happens with each one.
You issue the invoice in one of eighteen currencies. The exchange rate is pulled automatically from the NBP (Poland's central bank) table A for the day before the VAT obligation arises, with a fallback to the previous working day — or you enter the rate by hand.
Net and gross totals stay in the invoice currency, but the VAT amount is also printed in PLN. The rate, its date and the NBP table number all go into the FA(3) file sent to KSeF.
The invoice itself can be issued in one of ten languages, regardless of which language you use in the app — pin a language to a contractor and it applies automatically next time.
You add the "Odwrotne obciążenie" / "Reverse charge" note yourself, along with markers like VAT exemption, WDT (intra-EU supply) or export of goods. The one exception: the note appears on its own when a line uses the "oo" or "zw" VAT rate.
You file the VAT-UE recapitulative statement yourself, outside Biurko, and track exchange-rate differences between invoice and payment date on your own — neither one lives in the app.
The app runs in Polish, English and Ukrainian, and so do this site, the knowledge base and the changelog.
You connect Claude, ChatGPT, Cursor or another MCP-compatible assistant to your company, and it gets more than a hundred tools to work with — from issuing an invoice to sending it to KSeF and pulling the UPO back.
The token it connects with gets at most the permissions your own account has — never more.
Every call it makes is written to an audit log, and irreversible actions need your one-time confirmation before they go through.
You can pause or revoke its access at any moment.
A B2B contract is more than a bigger number on the invoice. These are the questions that come up first: what your ryczałt rate follows from, how the health contribution is worked out, and what you file once a year.
From the invoice to closing the year: what a tax month looks like in a one-person firm.
Where the ryczałt rate comes from, why borderline work stays unsettled, and how the rate works in the app.
Three brackets instead of a percentage: what comes off revenue first, and what still lands on you.
How JPK_EWP differs from JPK_V7, what goes into the file, and why you start the submission yourself.
What the 5% rate really covers, why ryczałt rules it out, and where the UD116 bill stands.
An IT accounting bureau typically runs 159–404 PLN a month. Here is what changes when you run the books yourself, in Biurko.
Already work with an accountant? They can step into your company on a role built just for them, and open finished registers instead of a stack of scans.
The specifics for a B2B contract — ryczałt, foreign clients, and what still happens outside the app.
Yes — from the revenue ledger built off your invoices. It is a running total for the year, using the rate you have set for that period, and it counts from revenue alone. ZUS (social security) contributions are not deducted, so treat the number as your calculation base, not the final amount you owe.
The revenue ledger, the monthly tax advance and the annual JPK_EWP (yearly ryczałt filing), sent to the tax office with the UPO attached. VAT registers and the JPK_V7 only come into play once you register for VAT — until then those screens simply do not apply to you.
Yes — in one of eighteen currencies, with the exchange rate pulled automatically from the NBP (Poland's central bank), and the document itself in one of ten languages. You mark reverse charge or the exemption on the line yourself. What stays outside the app: the VAT-UE recapitulative statement and the VIES contractor check.
Yes, if you connect one over MCP — but only within the permissions your own account has. Every call it makes is logged, an irreversible action like sending to KSeF needs your one-time confirmation, and you can revoke its access at any point.
Neither one lives in Biurko today. The app carries you through the month — invoicing, the ledger, the tax advance and the annual JPK_EWP — but the yearly PIT-28 return and your ZUS (social security) contributions are still handled outside it.
That is not the point of it. You keep running the numbers yourself, and if you have an accountant, they step into your company on their own role and see finished registers instead of a pile of scans — less back-and-forth, not a different person doing your books.
Create your account, connect KSeF, and issue the first invoice — the ledger and the tax advance follow from there.
Just your email to start — no long onboarding.
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