What Duolingo score do you need for Ohio State University?

For graduate admission, Duolingo, IELTS and TOEFL scores are valid for two years, and official results must reach Ohio State directly from the testing agency by your application deadline.

The graduate page says the Duolingo test cannot be used to exempt an admitted student from the English placement exam or from the Oral Proficiency Assessment for Graduate Teaching Associates. If you are awarded a teaching associateship and English is not your first language, you must certify your oral English before starting those duties.

IELTS comparison: both pages ask for IELTS 6.5 (the graduate page names the IELTS Academic test or IELTS Online).

Ohio State runs an intensive English programme, the American Language Program, with a separate application. The undergraduate page states that Ohio State does not offer conditional admission to students who enrol in it.

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