In English, it's similar to:
- "He must be at home."
- "She might be working."
- "They are probably tired."
1. Using müssen for a strong assumption
When you are almost certain something is true:
Structure
müssen + infinitive
Meaning
≈ 90–100% sure
Examples
- Er ist nicht im Büro. Er muss krank sein.
He isn't in the office. He must be sick.
- Das Licht brennt noch. Sie muss zu Hause sein.
The light is still on. She must be at home.
- Er spricht perfekt Deutsch. Er muss lange in Deutschland gelebt haben.
He speaks perfect German. He must have lived in Germany for a long time.
2. Using dürfte for a probable assumption
Very common at B1/B2 level.
Structure
dürfte + infinitive
Meaning
≈ 70–80% sure
Examples
- Er kommt nie zu spät. Er dürfte bald hier sein.
He is probably here soon.
- Das dürfte richtig sein.
That is probably correct.
3. Using könnte for a possible assumption
When something is possible, but you're not sure.
Structure
könnte + infinitive
Meaning
≈ 40–60% sure
Examples
- Wo ist Anna? Sie könnte im Garten sein.
She might be in the garden.
- Es ist sehr ruhig. Die Kinder könnten schlafen.
The children might be sleeping.
4. Using wohl
wohl means probably.
Meaning
≈ 70% sure
Examples
- Er ist wohl schon zu Hause.
He is probably already at home.
- Das ist wohl die beste Lösung.
That is probably the best solution.
- Sie hat den Bus wohl verpasst.
She probably missed the bus.
5. Using vielleicht
vielleicht means maybe/perhaps.
Meaning
≈ 50% sure
Examples
- Vielleicht hat er keine Zeit.
Maybe he doesn't have time.
- Vielleicht arbeitet sie heute von zu Hause.
Maybe she is working from home today.
Strength of certainty
| Expression | Certainty |
|---|---|
| müssen | Very high (90–100%) |
| dürfte | High (70–80%) |
| wohl | High (about 70%) |
| könnte | Medium (40–60%) |
| vielleicht | Medium/low (30–50%) |
Comparison
Imagine you call Peter but he doesn't answer:
Strong assumption
- Peter muss arbeiten.
Peter must be working.
Probable assumption
- Peter dürfte arbeiten.
Peter is probably working.
Possible assumption
- Peter könnte arbeiten.
Peter might be working.
Uncertain guess
- Vielleicht arbeitet Peter.
Maybe Peter is working.
Typical B1 Exam Examples
- Anna antwortet nicht. Sie muss beschäftigt sein.
Anna isn't answering. She must be busy.
- Das Auto steht vor dem Haus. Herr Meier dürfte zu Hause sein.
The car is in front of the house. Mr. Meier is probably at home.
- Es ist dunkel im Wohnzimmer. Die Kinder könnten schon schlafen.
It's dark in the living room. The children might already be sleeping.
- Vielleicht hat er sein Handy ausgeschaltet.
Maybe he switched off his phone.
Quick Rule
When making assumptions about the present:
- müssen = must be (very likely)
- dürfte = is probably
- wohl = probably
- könnte = might be
- vielleicht = maybe
A very common B1 sentence pattern is:
Er antwortet nicht. Er muss beschäftigt sein.
He isn't answering. He must be busy.
This is exactly the type of present-time assumption that appears frequently in B1 speaking and writing tasks.
Practice This Grammar Rule Interactively:
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