IP Box calculator for software developers

12 % lump sum, 19 % flat tax or IP Box 5 %? See what you keep from a B2B invoice in Poland. Rates as of 2026-01-01.

Monthly invoice, net (PLN) Business costs (PLN / month) Social security (ZUS)

Lump-sum rate Income qualifying for IP Box (%) The part of income that comes from code you author yourself. The rest is taxed at the 19 % flat rate.

Lump sum

PLN 14,623.66

net / month · 24.38 %

Health contribution: PLN 830.58
Income tax / month: PLN 2,119.00

costs do not reduce tax · no IP Box

Flat tax 19 %

PLN 13,536.84

net / month · 29.82 %

Health contribution: PLN 861.09
Income tax / month: PLN 3,175.31

no IP relief

Best option

IP Box 5 %

PLN 15,833.49

net / month · 18.33 %

Health contribution: PLN 861.09
Income tax / month: PLN 878.66

19 % advances, refund in the annual return

Best option: IP Box 5 %, PLN 15,833.49 net / month

Indicative result, assuming even income across the year. Simplifications: nexus ratio = 1 (own code, no purchased R&D), health contribution deducted only from the flat-taxed part. Whether your services qualify for IP Box depends on your contract and records. Not tax advice.

Frequently asked questions

What is IP Box in Poland?

IP Box is a preferential 5 % income tax rate on income from qualifying intellectual property, such as the copyright to software you write yourself. The rest of your income is taxed normally, for most developers at the 19 % flat rate.

Can a B2B software developer use IP Box?

Yes, if you create or develop software as part of your own business (R&D activity), transfer or license the copyright to your client, and keep a separate record of IP income. A well-drafted contract and records are essential; many developers also obtain an individual tax ruling.

Can I combine IP Box with the 12 % lump-sum tax?

No. IP Box works only with the progressive scale or the 19 % flat tax, because it requires full revenue and expense records. The 12 % lump sum is simpler to run but does not give you the 5 % rate.

When do I get the IP Box benefit?

The relief is claimed in the annual tax return. During the year you pay 19 % advances and get the difference back after filing for the full year. The calculator shows the monthly average over the year.

Want to use IP Box safely, with contract, records and tax ruling included? We run the books for B2B developers, in English.

B2B accounting for developers