What IELTS score do you need for the University of Gdańsk?

The page does not mention Duolingo, so it is not an accepted certificate there. It does accept several non-test routes: a bachelor's or master's diploma stating that studies were conducted entirely in English (or a supplement confirming it), a diploma in English philology or applied linguistics with at least 500 class hours in English, a preparatory course of at least nine months at B2 or higher in all four skills, an International Baccalaureate Diploma in the main language, or a European Baccalaureate in L1 or L2.

Certificates from telc and LanguageCert are also listed. For telc the page gives no score thresholds, so ask the university before relying on one.

The recruitment site lists English-taught programmes such as International Business, Logistics and Mobility, Finance and Accounting, Criminology and Criminal Justice, Cultural Communication, Global Studies, Marine Biotechnology and Quantum Information Technology, at first and second cycle. The recruitment page itself does not state a language certificate rule, so use the certificates page above for the score.

Individual programmes can add their own selection steps, so read the programme page for any extra test or interview.

Requirements vary by programme and change between admissions cycles. The score that binds you is the one on your University of Gdańsk programme page and in your offer, so check it there before you book a test.