En, Pendant, Pour, Dans: Measuring Time and Placing Events
This is the second of two pages on expressing duration in French. The first page covered il y a and depuis, the pair used for an ongoing state or a point back in time. This page covers four more constructions: en, pendant, pour, and dans.
En answers « how long did it take to get this done ». There's always a specific result at the end, a book written, the housework finished, and en tells you the time that result took to reach.
In both cases, there's a clear endpoint, a finished book, a clean house, and en tells you how long it took to get there.
Pendant measures how long an action went on while it was happening, with no particular finish line in mind. It works with the present, the future, and the passé composé, and in the passé composé it can often be left out entirely without changing the meaning.
The first example shows that pendant can be dropped in the present too, not only in the passé composé. The next two show pendant in the passé composé, and the last in the future, the construction works across all three. The last example also uses pendant with a noun rather than a number: pendant + event describes something happening within that stretch of time.
Both can translate to « in » or « for » a length of time in English, which is exactly why they get mixed up. The question to ask is whether the sentence is about reaching a specific result, or just about the action itself continuing for a while.
The first has a destination: two hours is how long it took to arrive. The second has no destination in view, two hours is simply how long the driving went on.
Pour is narrower than it looks. It's used for a duration decided on in advance, almost always with aller, venir, or partir, and it doesn't appear with rester. Just as important: pour is never used for a duration that's already over, that's pendant's job alone.
Both describe a length of time settled on before the fact. A completed stay, on the other hand, always takes pendant or nothing at all: je suis resté trois semaines à Londres, never pour.
Dans doesn't measure a duration at all. It places an event at a specific point in the future, counted from now, which is easy to mistake for en since both involve a number of days or hours.
None of these three say how long the arriving, the leaving, or the calling back will take. Each one places that event at a fixed point in the future, in two days, in two hours, in ten minutes.
- How long it took to reach a result or finish line. J'ai repeint la cuisine en deux jours. (I repainted the kitchen in two days.)
- How long an action lasted or lasts, no finish line implied. Works in the present, future, or passé composé (where it can often be dropped). Il a habité (pendant) cinq ans à Londres. (He lived in London for five years.)
- A duration decided in advance, mostly with aller, venir, partir. Never for a completed past duration. Il part pour trois mois en Australie. (He's going to Australia for three months.)
- Places an event at a fixed point in the future, not how long it lasts. Nous arriverons dans deux jours. (We'll arrive in two days.)