One of the trickiest aspects of German grammar for English speakers is choosing the right preposition for time expressions. In English, we use "on," "in," and "at" with some flexibility, but German has very specific rules. The prepositions am, im, um, seit, bis, and von...bis each serve a distinct purpose when talking about time. Let's break them down one by one.
am — Days and Parts of the Day
"Am" is used with days of the week and parts of the day. It is a contraction of "an dem" (dative). Examples: am Montag (on Monday), am Wochenende (on the weekend), am Morgen (in the morning), am Abend (in the evening). Note the exception: "in der Nacht" (at night) uses "in," not "am." Another exception is "am Mittag" (at noon), which is correct.
im — Months and Seasons
"Im" is used with months and seasons. It is a contraction of "in dem" (dative). Examples: im Januar (in January), im Sommer (in summer), im Winter (in winter), im März (in March). You can also use "im" with longer time periods: im 21. Jahrhundert (in the 21st century), im Jahr 2026 (in the year 2026) — though "2026" alone without "im Jahr" is also common.
um — Clock Times
"Um" is used exclusively for clock times — the exact hour or minute. Examples: um 8 Uhr (at 8 o'clock), um Mitternacht (at midnight), um 14:30 (at 2:30 PM). This is one of the easiest prepositions to remember because it always means "at" a specific time on the clock.
seit — Since / For (Ongoing Actions)
"Seit" translates to "since" or "for" and is used for actions or states that started in the past and continue into the present. It takes the dative case. Examples: Ich lerne seit drei Monaten Deutsch (I have been learning German for three months), Seit 2020 wohne ich in Berlin (I have been living in Berlin since 2020). Important: German uses the present tense with "seit," while English uses the present perfect.
bis — Until / By
"Bis" means "until" or "by" and marks an end point in time. When used alone, it takes the accusative. Examples: bis Freitag (until Friday), bis nächste Woche (until next week), bis 18 Uhr (by 6 PM). When "bis" is combined with another preposition, the case follows that second preposition: bis zum Sommer (until summer — "zum" is dative).
von...bis — From...To
The combination "von...bis" expresses a time range. Examples: von Montag bis Freitag (from Monday to Friday), von 9 bis 17 Uhr (from 9 to 5), von Januar bis März (from January to March). Both "von" and "bis" here are straightforward — "von" takes the dative case.
Summary Table
| Preposition | Used With | Example |
|---|---|---|
| am | Days, parts of day | am Montag, am Abend |
| im | Months, seasons | im Juli, im Frühling |
| um | Clock times | um 10 Uhr |
| seit | Since / for (ongoing) | seit zwei Jahren |
| bis | Until / by | bis Freitag |
| von...bis | From...to (range) | von 8 bis 12 Uhr |
Common Mistakes to Avoid
- Don't say "in Montag" — it's always "am Montag." Days require "am."
- Don't say "am Januar" — months use "im," not "am."
- Don't say "auf 8 Uhr" — clock times always use "um."
- Don't use past tense with "seit" — German uses present tense: "Ich lerne seit..." not "Ich habe gelernt seit..."
- Remember "in der Nacht" is the exception — nighttime does not use "am."
When do I use am, im and um in German?
These three prepositions cover most time expressions. Use am for days and parts of the day (am Montag, am Morgen), im for months, seasons and years (im Januar, im Sommer), and um for clock times (um 8 Uhr). Learning this simple split handles the majority of everyday time phrases.
How do I say dates and times in German?
For clock times use um (um 15 Uhr); for days use am (am Freitag); for months and seasons use im (im Dezember, im Winter). Note that some expressions use no preposition at all, like naechste Woche (next week) or heute (today). Learn the common ones as fixed phrases.
What is the difference between am and im for time?
Use am for specific days and daytimes (am Sonntag, am Nachmittag) and im for longer periods like months, seasons and years (im Mai, im Herbst). A simple memory aid: am for days, im for months and seasons, um for the clock.
What about seit and bis — how are they different from am, im, um?
Seit and bis mark the edges of a time span rather than a single point. Seit (since) looks backward from now — seit 2020 (since 2020), seit drei Jahren (for three years, literally 'since three years') — and always pairs with the present tense in German even when English would use a past tense. Bis (until) looks forward to an endpoint — bis Freitag (until Friday), bis 18 Uhr (until 6pm). Combined, von...bis (from...to) brackets a range: von Montag bis Freitag. Once am/im/um feel automatic, seit and bis are the next natural pair to drill, since they show up constantly in scheduling and small talk.
German time prepositions are simple: am for days and daytimes, im for months and seasons, um for clock times — learn the split and most time phrases fall into place.
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