The subjunctive II of modal verbs (könnte, sollte)

Advice and possibility with "sollte" and "könnte"

To give advice or talk about hypothetical possibilities—especially in emergencies—we use the Subjunctive II (Konjunktiv II) forms of modal verbs.

• sollen (to be supposed to) becomes sollte (should)
• können (can) becomes könnte (could)

Notice that sollte is identical to its simple past form, while könnte takes its past form and adds an umlaut.

Obligation and probability with "müsste", "dürfte", and "wollte"

The other modal verbs follow a similar pattern: they take their past tense form and add an umlaut if the original verb had an a, o, or u. (Like sollen, wollen does not take an umlaut, so wollte is also identical to its simple past form).

• müssen (must) becomes müsste (would have to)
• dürfen (may) becomes dürfte (would be allowed to / is likely to)
• wollen (want to) becomes wollte (would want to)

Note: In everyday German, dürfte is frequently used to express a high probability, meaning something should or is likely to happen.

Conditional emergencies with "wenn"

Just like with hätte and wäre, you can use these modal verbs in conditional sentences starting with wenn (if).

Remember your word order rules: wenn kicks the conjugated verb to the very end of its clause. If the wenn-clause comes first, the main clause immediately follows it and starts directly with its own conjugated verb.