Probability with verbs (-dır)

Making Assumptions with -dır

You have already seen the suffix -dır used for objective facts or formal announcements. In everyday conversation, attaching -dır (and its vowel harmony variants like -dir, -tır, -tur) to a conjugated verb expresses an assumption, a strong deduction, or a probability. It is how you say someone "must have" done something or "is probably" doing something.

When you attach -dır to the reported past tense (-mış / -miş), the resulting -mıştır form means "must have" or "probably has." This is commonly used when guessing why someone is late or what happened.

Adding Adverbs of Probability

Even though -dır implies a deduction on its own, you will frequently hear it paired with adverbs to clarify the degree of certainty.

Using words like herhalde (I suppose / probably) or muhtemelen (probably) emphasizes that you are making a likely guess.

Adding kesin (definitely) shows a confident deduction. You haven't seen it happen, but based on the evidence, you are certain it "must have" happened.

Present Assumptions

You can also make assumptions about what is happening right now by attaching the suffix to the present continuous tense (-ıyor). Because the final vowel of -ıyor is always o, the assumption suffix is always -dur.

The form -ıyordur translates to "must be doing" or "is probably doing." It is often used alongside past assumptions to describe the current result of a past event.