Do I need German or English for a master's, and which language certificates are accepted?

Which language you need depends on the programme's language of instruction. Always check the exact requirement on the programme page; universities differ.

German-taught programmes: Most require C1 level. Commonly accepted certificates are DSH (at least DSH-2), TestDaF (for example 16 points in total or at least 4 in every section), telc Deutsch C1 Hochschule and the Goethe-Zertifikat C1. A bachelor's degree taught in German is usually accepted too. Some programmes may require a lower or higher level.

English-taught programmes: Usually B2 to C1 level; a very common requirement is IELTS Academic 6.5 or a TOEFL iBT score of around 90. Cambridge certificates are accepted too. If your bachelor's was taught in English, that often counts instead of a language certificate; ask your university for a confirmation letter.

Validity: Some programmes require language test results to be no more than 2 to 3 years old.

A master's without German: There are many English-taught master's programmes in Germany, and you can study without German. But German makes a big difference in daily life, dealing with authorities and finding a job after graduating. Use the university's free or low-cost language courses during your master's.