To say when something happens in German, you pick the preposition by the size of the time unit — and each one comes locked to a fixed case you never have to choose. Clock times take um, days and dates take am, months and seasons take im, and durations have their own set. This page sorts the time prepositions by the unit they attach to, so you can grab the right one instantly. The one structural surprise for English speakers — seit with the present tense — gets its own section.
The time prepositions by unit
| Time unit | Preposition | Example | English |
|---|---|---|---|
| clock time | um | um acht Uhr | at eight o'clock |
| part of day | am | am Morgen, am Abend | in the morning/evening |
| day / date | am | am Montag, am 3. Mai | on Monday, on May 3rd |
| month / season / year-context | im | im Januar, im Sommer | in January, in summer |
| "in X time" (future point) | in + dative | in einer Woche | in a week |
| since / for (up to now) | seit + dative | seit zwei Jahren | since / for two years |
| ago | vor + dative | vor drei Tagen | three days ago |
| before / after | vor / nach + dative | vor dem Essen, nach der Schule | before the meal, after school |
| until | bis | bis morgen | until tomorrow |
| intended duration | für + accusative | für drei Tage | for three days |
| during | während + genitive | während der Ferien | during the holidays |
| around (approximate) | gegen + accusative | gegen acht | around eight |
| from … on | ab + dative | ab Montag | from Monday on |
The first thing to notice: the case is baked into each preposition for time, so you don't make a wo/wohin decision the way you do in space. um and für and gegen take the accusative; am, im, seit, vor, nach, in, ab take the dative; während takes the genitive. Learn the preposition and its case as one chunk.
Clock time: um
For a specific point on the clock, use um. English "at eight o'clock" → German um acht Uhr. The case is accusative, but it almost never shows because clock numbers don't take articles.
Der Film fängt um acht Uhr an.
The film starts at eight o'clock. — um for clock time. (informal)
Wir treffen uns um halb sieben vor dem Kino.
We're meeting at half past six in front of the cinema. — um halb sieben = at 6:30.
For an approximate time, swap um for gegen (around): gegen acht = around eight.
Ich bin gegen acht zu Hause.
I'll be home around eight. — gegen for an approximate time.
Days, dates, and parts of the day: am
am (= an dem) covers days of the week, calendar dates, and parts of the day. English uses "on" for days and dates but "in" for parts of the day — German uses am for all three (with one famous exception below).
Am Montag habe ich einen Termin beim Zahnarzt.
On Monday I have a dentist's appointment. — am for a weekday.
Mein Geburtstag ist am 3. Mai.
My birthday is on May 3rd. — am for a date.
Am Abend gehen wir oft spazieren.
In the evening we often go for a walk. — am for a part of the day.
The exception to memorize: in der Nacht (at night) uses in, not am — and nachts as an adverb is even more common. Everything else in the "part of day" group is am: am Morgen, am Vormittag, am Mittag, am Nachmittag, am Abend.
Months, seasons, years: im
im (= in dem) covers months, seasons, and longer stretches.
Im Januar ist es hier meistens grau und kalt.
In January it's usually grey and cold here. — im for a month.
Im Sommer fahren wir immer ans Meer.
In summer we always go to the seaside. — im for a season.
Note that bare years take no preposition: you say 2026 or im Jahr 2026, but never in 2026 (a common English-influenced error — see below).
Duration up to now: seit + present tense
This is the structural surprise. seit means since (a starting point) or for (a span running up to the present). The trap is the tense: German keeps the verb in the present because the action is still ongoing — while English switches to the present perfect ("have been learning").
Ich lerne seit drei Jahren Deutsch.
I have been learning German for three years. — German present (lerne), English present perfect.
Seit Montag habe ich Husten.
I've had a cough since Monday. — point in time → seit + present.
Before, after, ago, in X time
vor + dative means both before (in sequence) and ago (a point in the past). nach + dative means after. in + dative points to a future moment ("in X time").
Vor dem Essen wasche ich mir die Hände.
Before the meal I wash my hands. — vor = before. (informal)
Vor drei Tagen habe ich sie zuletzt gesehen.
I last saw her three days ago. — vor = ago.
Nach der Schule gehen wir immer zusammen nach Hause.
After school we always walk home together. — nach = after.
In einer Woche fängt der Urlaub an.
The holiday starts in a week. — in + dative for a future point.
Be careful with the vor pair: vor dem Essen (before the meal, sequence) and vor drei Tagen (three days ago, past point) use the same word. Context — a noun event vs. a span of time — tells them apart.
Until, intended duration, during, from … on
bis = until (an endpoint). für + accusative = for an intended/planned duration. während + genitive = during. ab + dative = from … on.
Das Geschäft hat bis 20 Uhr geöffnet.
The shop is open until 8 p.m. — bis = until.
Wir fahren für drei Tage nach Wien.
We're going to Vienna for three days. — für for a planned duration.
Während der Pause habe ich kurz telefoniert.
During the break I made a quick call. — während + genitive.
Ab Montag arbeite ich wieder im Büro.
From Monday on I'm working in the office again. — ab for a starting point onward.
A subtle point worth knowing: für marks a duration you plan or intend ("we'll go for three days"), while seit marks a duration that has already run up to now. So "I've been here for three days" (already elapsed) is seit drei Tagen, but "I'm staying for three days" (planned) is für drei Tage. Mixing them up changes the meaning.
How this differs from English
English leans heavily on two prepositions — "at" for clock time and "in/on" for everything else — and lets context sort out the rest. German distributes the work across many prepositions keyed to the unit: um only for the clock, am only for days, im only for months. The biggest English-interference errors come from translating "in" and "at" literally: English "at eight" tempts in acht (wrong — it's um acht), and English "in 2026" tempts in 2026 (wrong — bare year or im Jahr 2026). The seit + present mismatch is the deepest one, because it isn't a vocabulary swap — it's a different way of locating an ongoing situation in time.
Common Mistakes
❌ Der Film fängt in acht Uhr an.
Incorrect — clock time takes um, not in.
✅ Der Film fängt um acht Uhr an.
The film starts at eight o'clock.
❌ Ich habe seit drei Jahren Deutsch gelernt.
Incorrect — seit with an ongoing activity takes the present tense, not the perfect.
✅ Ich lerne seit drei Jahren Deutsch.
I've been learning German for three years.
❌ In 2026 fahren wir nach Japan.
Incorrect — bare years take no preposition; use the year alone or 'im Jahr 2026.'
✅ 2026 fahren wir nach Japan.
In 2026 we're going to Japan.
❌ Wir treffen uns an acht Uhr.
Incorrect — am is for days/dates, not clock time; clock time is um.
✅ Wir treffen uns um acht Uhr.
We're meeting at eight o'clock.
❌ Ich bleibe seit drei Tage in Wien.
Incorrect — a planned stay is für + accusative; seit is for elapsed time and takes the dative.
✅ Ich bleibe für drei Tage in Wien.
I'm staying in Vienna for three days.
The errors cluster around two English habits: translating "at/in" without checking the time unit, and forcing English perfect tense onto seit. Anchor each preposition to its unit — clock → um, day → am, month → im — and keep the present tense after seit.
Key Takeaways
- Pick the time preposition by unit: clock → um, day/date/part-of-day → am, month/season → im.
- The case is fixed per preposition — um/für/gegen accusative, am/im/seit/vor/nach/in/ab dative, während genitive — so there's no wo/wohin decision.
- seit
- an ongoing situation takes the present tense (where English uses the present perfect).
- vor = both "before" and "ago"; in + dative = "in X time"; für = planned duration vs. seit = elapsed duration.
- Bare years take no preposition (2026, not in 2026); in der Nacht / nachts is the exception to the am part-of-day rule.
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Start learning German→Related Topics
- Accusative of Time, Duration, and MeasureB1 — German uses the bare accusative — no preposition — for definite time points, durations, and measurements: jeden Tag, nächsten Montag, einen Monat lang, einen Meter hoch.
- Using the Present Tense (No Progressive in German)A2 — The full range of the German present tense — habitual, ongoing, general, and future — and why German has no -ing progressive.
- Dative Prepositions in UseA2 — The everyday dative prepositions — aus, bei, mit, nach, seit, von, zu — what each one means and how to use them naturally.
- Dates, Days, and YearsA2 — German dates use an ordinal day in day-month-year order (1.5.2026), days and months are masculine and take am/im, and years are read as plain numbers or in hundreds — with no preposition before a bare year (never in 1990).
- Telling TimeA2 — How to tell time in German, including the trap that makes English speakers miss appointments: halb drei means 2:30, not 3:30.
- Time ExpressionsA2 — When to drop the preposition (jeden Tag, accusative), when to use one (am Montag, im Januar), plus übermorgen, ab und zu, and the seit + present rule.