How do I say should in French?

should meaning ought to

Where you could replace should with ought to and it would have more or less the same meaning, then a common translation in French is to use the conditional tense of the verb devoir. As in English, it is followed by the infinitive. For example:

je/tu devrais venir
I/you should come
il devrait faire ses devoirs
he should do his homework
on devrait pouvoir venir
we should be able to come
vous devriez l'aider
you should help him

How to translate should have ... into French

The formula should have ... is translated into French using the conditional perfect of devoir. This means that you use:

conditional of avoir + + infinitive

For example:

j'aurais dû venir
I should have come
tu aurais dû lui dire que tu étais malade
you should have told him that you were ill
il n'aurait pas dû manger tant de chocolat
he shouldn't have eaten so much chocolate

Note from the last example that you can say shouldn't have by negating the verb in the usual way.

should meaning would

In formal, old-fashioned usage, should is sometimes used to mean would.

Where you could change should to would with essentially no change of meaning, then use the conditional tense as usual in French.

Since using should in this way is essentially formal (and for many speakers old-fashioned), you could try to find a formal verb in French. For example, for I should like ... a possibility is to say j'aimerais ... or je souhaiterais ... rather than je voudrais .... It's often not possible to make such a distinction in French, however.

should introducing a condition

In English, the construction if I/you should ... is sometimes used to mean something similar to if ever I/you .... In French, a possible translation is therefore to use si jamais ... ("if ever ..."):

si jamais vous visitez la France, allez voir la Tour Eiffel
if you should (ever) visit France, go and see the Eiffel Tower

"it is surprising that he should ..." etc

In formal or careful usage, English sometimes uses should to emphasise the speaker's reaction to something rather than stating that something has taken place. (In a formal analysis, this is sometimes called a non-assertion.) For example:

I was really surprised that he should decide to come

In this sentence, the speaker chooses to say should decide rather than decided to emphasise their reaction to the decision rather than simply stating that the decision was made.

In French, this use of should generally corresponds to the subjunctive. The subjunctive is a special verb form used to make a non-assertion. (English no longer has subjunctive forms of the verb; the nearest equivalent to the subjunctive in English is using other constructions such as should ..., might ... as in the above example.) So to translate the above example into French using the subjunctive, we might say:

cela m'a vraiment étonné qu'il ait décidé de venir

The construction ait décidé means roughly the same as a décidé = (has) decided, but ait is the subjunctive form of avoir rather than the usual present tense form that you'd use to form the perfect tense.

See also

 How to translate would into French
 What is the subjunctive?