Translative for Deadlines and Purposes

The translative case, -ksi, is best known for marking what something becomes (vanhaksi, "old"; lääkäriksi, "into a doctor"). But it has a second, equally everyday job in the world of time: it turns a time expression into a target or an allotment. Perjantaiksi means "by Friday"; viikoksi means "for a week". Both senses share one idea — a time treated as an endpoint you aim at or a span you set aside — and both stand in deliberate contrast to the essive, which marks a time you are simply in.

Deadlines: "by" a time

Attach -ksi to a time expression and it becomes the moment by which something must be ready or done. English uses "by"; Finnish loads it onto the ending:

The logic is that -ksi points at the time as the goal the action is aiming toward — the same "arrival at an endpoint" meaning it carries when it marks a change of state. Valmis perjantaiksi frames Friday as the deadline the work is being driven toward, exactly as valmis lääkäriksi would frame "doctor" as the endpoint of studying.

Allotments: "for" a stretch of time

The second time use marks a span set aside for something — how long you are leaving, renting, borrowing, or booking. Again English says "for", and Finnish says -ksi:

Here -ksi frames the time as a container of intended duration: the week is the stretch allotted to the trip, the summer is the stretch allotted to the rental. This use pairs naturally with verbs of departing, reserving, and lending — lähteä, jäädä, varata, vuokrata, lainata — the verbs of setting something aside for a period.

The subtle part: allotted span vs measured duration

Finnish draws a line that English blurs completely, because English says "for a week" for both. The translative viikoksi is the span you allocate — typically forward-looking, tied to a plan. A plain accusative viikon (genitive-shaped) is the span you measured out — the actual, completed length of an event:

Notice the verbs: mennä (a departure, allotting a future week) takes -ksi; olla (a completed stay, measuring elapsed time) takes the accusative viikon. And when the duration is counted with a number, it is a plain partitive, not the translative:

So three distinct patterns, all "for … weeks" in English: viikoksi (allotted, translative), viikon (measured, accusative), kolme viikkoa (counted, partitive). Reach for -ksi only when you mean a period reserved for a purpose.

Coming second: the translative of rank

A small extra use worth recognising: with jäädä ("be left") and tulla ("come, place"), the translative marks a finishing position:

This is the ordinary "end-result" translative again — the place where the runner or team ends up — just applied to ranks (ensimmäiseksi, toiseksi, viimeiseksi) instead of states.

The minimal pair: maanantaina vs maanantaiksi

Everything on this page lives one ending away from the essive, and a single word shows the whole contrast. The essive marks a point you are inside; the translative marks a target you are aiming at:

Maanantaina answers "when does it happen?" — on Monday itself. Maanantaiksi answers "by when is it due?" — Monday as the boundary. The full state-vs-goal comparison between the two cases lives on the essive vs translative page.

Two form reminders carry over from the translative proper: the ending is harmony-invariant — always -ksi, never -ksä (so kesäksi, not kesäksä) — and it gradates to the weak grade like the genitive: viikko → viikoksi (kk → k), mökki → mökiksi.

Common Mistakes

Key Takeaways

• The translative -ksi marks a time as a deadline ("by"): perjantaiksi, huomiseksi, jouluksi, kuudeksi.
• It also marks an allotted span ("for"): viikoksi, kesäksi, kahdeksi yöksi — the period set aside for something.
• Distinguish it from measured duration: viikoksi (allotted) vs the accusative viikon (elapsed) vs the partitive kolme viikkoa (counted).
• It marks finishing rank with jäädä / tulla: jäi toiseksi, tuli ensimmäiseksi.
• Contrast with the essive: maanantaina = "on Monday" (a point); maanantaiksi = "by Monday" (a target).
• The ending is invariant -ksi (never -ksä) and gradates to the weak grade: viikko → viikoksi.