Invoicing in Poland, KSeF and the UPO, the ryczałt and the JPK files — written out step by step.
We write about invoicing in Poland — what belongs on a document, how to fix a mistake, and what exactly changed when the rules did. More and more often about the tax side of a B2B contract too: the ryczałt, the revenue ledger, the monthly advance and the annual JPK_EWP. And about running a firm day to day, with the paperwork finally out of the foreground. KSeF as well, but it is only one of the topics.
inFakt is a mature Polish accounting ecosystem with a free KSeF plan. If you run a single Polish entity and need bookkeeping in the same system, inFakt is hard to beat, and we will say so plainly. Biurko.io solves a different problem: many companies in one panel, certificate-based KSeF authentication instead of tokens, readable KSeF error messages, and a Ukrainian-language interface. Here is how to tell which one you need.
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Debts at ZUS and the Polish tax office can be spread into instalments or deferred, replacing standard late-payment interest with a lower prolongation fee. Neither authority will offer an agreement automatically, so the taxpayer must file a well-justified application. Submitting a request does not instantly halt enforcement, making early preparation essential.
Foreign sales revenue in Poland falls under four distinct VAT classifications, while income tax follows standard PIT rules. B2B invoices for foreign clients enter KSeF starting 1 April 2026. Securing 0% VAT or reverse charge treatment depends on valid buyer IDs and timely submission of shipping proofs.
An active sole proprietorship in Poland generally requires filing an annual tax return even if no sales occurred during the year. Depending on your tax structure, a zero PIT-36, PIT-36L or PIT-28 for 2026 must be submitted by 30 April 2027.
Running bookkeeping without an accountant in Poland is completely legal for a sole proprietorship. Entrepreneurs can manage their own flat-rate revenue register and submit required monthly JPK_V7M filings directly to the tax office. Success relies on maintaining proper records and keeping up with recurring monthly tax and ZUS deadlines.
From 1 January 2026, the tax-deductible cost cap for most combustion passenger cars in Poland is set at PLN 100,000, limiting lease and depreciation deductions. Business owners deduct 50% VAT by default, while claiming 100% VAT requires filing form VAT-26 within 7 days and maintaining a detailed mileage log. Running costs remain subject to a separate 75% tax deduction rule for mixed business and personal use.
Doing your own bookkeeping as a Polish sole proprietor (JDG) is fully legal under local tax regulations. Business owners on flat-rate tax can handle their revenue register, VAT filings, and ZUS forms independently. Modern software integrating with KSeF automates the primary monthly compliance tasks.
Closing a sole proprietorship in Poland requires deregistration from CEIDG alongside specific tax obligations. Active VAT payers must submit form VAT-Z, carry out a closing stocktake and file the final JPK_V7 return by the 25th day of the following month. Business records and tax returns must be archived for 5 years from the end of the tax year.
Once a KSeF number is assigned, an invoice cannot be deleted or modified in the system. Errors must be fixed by issuing a structured corrective invoice or a zero correction. If you issued an invoice with a wrong NIP, you must zero the original document and issue a new one.
Sole proprietors in Poland must issue B2B invoices via KSeF from 1 January 2027 at the latest. Until 31 December 2026, small businesses with monthly invoiced sales under PLN 10,000 gross remain exempt from structured issuing. Receiving purchase invoices in KSeF applies to all registered taxpayers from 1 February 2026.
Registering a sole proprietorship (JDG) in Poland via CEIDG is free and requires choosing a tax form, ZUS path, and VAT status. Until 31 December 2026, small businesses billing up to PLN 10,000 gross per month may invoice outside KSeF. Full e-invoicing becomes mandatory for all sole proprietors on 1 January 2027.
Standard monthly ZUS contributions in Poland will rise to 2,052.15 PLN in 2027 before the health contribution is added. Entrepreneurs can manage their books across six different setups, ranging from free government tools to full accounting services. Choosing the right method balances administrative time against potential compliance risks in KSeF.
After the Fakturownia security breach, all external API keys must be replaced to secure integration channels. The correct workflow requires generating a new token, updating settings, testing the connection, and only then revoking the old key. This prevents service interruptions during invoice generation.
Invoicing in a foreign language is completely legal for B2B transactions in Poland, provided the VAT amount is shown in PLN. From 1 April 2026 most sole proprietorships must issue structured invoices via KSeF using the FA(3) schema.
A B2B developer in Poland must manage KSeF invoicing, ZUS and ryczałt tax by the 20th, and JPK_V7M by the 25th of each month. For monthly invoices exceeding PLN 10,000 gross, KSeF has been mandatory since 1 April 2026. Learn how to calculate your 12% flat-rate tax and health contributions.
Sending an invoice to KSeF is only the first step of your monthly routine. The invoice must be correctly recorded in your VAT registers with its KSeF number, and then reported in JPK_V7M, ryczałt tax and ZUS. Follow this practical guide for a sole trader to see how the systems interact.
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