What Duolingo score do you need for the University of Idaho?

Both pages say all tests must have been taken within two years of the semester for which you are applying. Neither page gives DET subscores, a separate assistantship level or Duolingo sending instructions.

On the same pages, IELTS is 6.0 for undergraduates and 6.5 overall for graduate study.

Select graduate programmes, such as biological engineering and chemical engineering, may admit applicants who qualify academically but have not met the English minimum. You enrol in the American Language and Culture Program (ALCP) until you meet the university and department requirements; if that does not happen within two years, you must reapply. Undergraduates can meet the requirement by completing ALCP. No DET entry level is given.

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