German Adjective Declension Calculator
See why German picks -e, -en, -er, -es, or -em. Choose an article type, gender, case, or preposition to build the live phrase and inspect all 16 slots at once.
Step-by-step logic
- 1. Definite / der-word "der" already carries the clear gender and case marker for Masculine (der) in Nominative (subject).
- 2. After a marked der-word, German adjectives only take the soft "-e" (inside the 5 Nominative/Accusative Pan/Box slots) or "-en" everywhere else -> "-e".
Preposition-to-Case Helper
Click any preposition below to automatically switch to its required German case and preview it with your noun phrase.
Full 4×4 Matrix (Weak declension for gut)
Click any cell to inspect its logic| Case | Masculine (der) | Feminine (die) | Neuter (das) | Plural (die) |
|---|---|---|---|---|
| Nominative | ||||
| Accusative | ||||
| Dative | ||||
| Genitive |
The grammar behind adjective endings
- Adjective basics (predicative vs. attributive) →When adjectives take endings — and when they stay unchanged (Der Kaffee ist gut).
- Weak declension (der-words) →Why definite articles leave adjectives with only -e or -en.
- Mixed declension (ein-words) →How ein, kein, and mein force strong endings in 3 unmarked slots.
- Strong declension (no article) →Borrowing der/die/das signals directly onto the adjective.
- Two-way prepositions (Wo vs. Wohin) →Choosing Dative vs. Accusative with in, an, auf, über, unter.
- Prepositions by case →Complete Accusative, Dative, and Genitive preposition lists.
Frequently Asked Questions: German Adjective Endings
When do German adjectives take an ending?
German adjectives take endings only when they stand directly before a noun (attributive position: "der gute Kaffee"). When they come after sein, werden, or bleiben (predicative position: "Der Kaffee ist gut"), they never take an ending.
What is the difference between weak, mixed, and strong adjective declension?
It depends on what precedes the adjective. Weak declension follows der-words (der, dieser, jeder), which already show gender and case, so adjectives take only -e or -en. Mixed declension follows ein-words (ein, kein, mein), which lack endings in Nom. M/N and Akk. N. Strong declension has no article, so the adjective carries the full case ending itself.
Why does "hoch" become "das hohe Haus" and "teuer" become "teure"?
A handful of German adjectives adjust their stem before endings: hoch drops its -c- (hoh- + -e = hohe), while adjectives ending in -el (dunkel → dunkle) and often -er after a vowel (teuer → teure, sauer → saure) drop the unstressed -e- inside the stem.
Why is Genitive Masculine/Neuter strong "-en" instead of "-es"?
In phrases without an article like "trotz kalten Wetters", the noun itself already ends in -(e)s to signal Genitive, so modern German uses "-en" on the adjective ("kalten") rather than repeating "-es".
Which prepositions trigger which German case?
durch, für, gegen, ohne, um always take Accusative; aus, außer, bei, mit, nach, seit, von, zu always take Dative; wegen, während, trotz, statt normally take Genitive in standard written German; and the 9 two-way prepositions (an, auf, hinter, in, neben, über, unter, vor, zwischen) take Dative for static location (Wo?) and Accusative for motion toward a target (Wohin?).