Adjective Declension with Indefinite Articles in German

In Brief

After ein, eine, kein, and possessives such as mein and dein, an adjective takes a mixed ending. Learn these three headline forms first: ein großer Mann, eine große Frau, ein großes Kind. In most other forms the adjective ends in -en, especially in the dative and genitive and throughout the plural.

Overview

When a German adjective comes before a noun, its ending changes: compare ein alt-er Freund, eine alt-e Freundin, and mit einem alt-en Freund. This change is called adjective declension. The ending helps identify the noun's gender (masculine, feminine, or neuter), number, and case—the grammatical form that shows the noun's job in the sentence.

English adjectives do not change this way: “a new bag,” “I have a new bag,” and “with a new bag” all use new. German distributes grammatical information across the article and adjective. If an ein-word does not have a visible ending, the adjective must often supply one: ein neu-es Auto. If the article already has a clear ending, the adjective normally uses -en: mit einem neu-en Auto.

This pattern is introduced at A2 and builds directly on adjective endings after definite articles. It applies not only to ein/eine (“a/an”), but also to kein (“no/not any”) and possessive determiners—words such as mein (“my”) and dein (“your”) that introduce a noun.

How It Works

Which words trigger this pattern?

The mixed pattern follows the ein-words:

• ein, eine — a/an; unlike English, there is no plural indefinite article
• kein, keine — no, not a, not any
• mein, dein — my, your (informal singular)
• sein, ihr — his/its, her/their
• unser, euer — our, your (informal plural)
• Ihr — your (formal)

These words take article endings themselves: ein, eine, einen, einem, and so on. The adjective ending depends on what that article form already reveals.

The beginner rule

Use this short route for the forms you meet most often:

1. In the nominative (usually the subject), use -er for masculine, -e for feminine, and -es for neuter: ein netter Mann, eine nette Frau, ein nettes Kind.
2. In the masculine accusative (usually a direct object—the person or thing directly affected), use -en: Ich sehe einen netten Mann.
3. Feminine and neuter accusative look like their nominative forms: eine nette Frau, ein nettes Kind.
4. Use -en in every dative form and in the plural: mit einem netten Mann, meine netten Freunde.

That compact rule covers most everyday situations.

Complete mixed-declension table

The bold letters are adjective endings.

Case	Masculine	Feminine	Neuter	Plural
Nominative	ein neuer Kurs	eine neue Schule	ein neues Buch	keine neuen Bücher
Accusative	einen neuen Kurs	eine neue Schule	ein neues Buch	keine neuen Bücher
Dative	einem neuen Kurs	einer neuen Schule	einem neuen Buch	keinen neuen Büchern
Genitive	eines neuen Kurses	einer neuen Schule	eines neuen Buches	keiner neuen Bücher

The nominative commonly marks the subject—the person or thing doing the action. The accusative commonly marks the direct object. The dative often marks a recipient or follows prepositions such as mit, bei, and von. The genitive commonly expresses possession or association and is more frequent in formal written German.

A useful visual shortcut is that only five singular cells do not use -en:

• masculine nominative: -er
• feminine nominative and accusative: -e
• neuter nominative and accusative: -es

Everything else uses -en.

Why the endings are called “mixed”

The adjective alternates between endings that carry clear information and the common weak ending -en. In ein großer Hund, bare ein does not visibly mark masculine nominative, so -er does. In einen großen Hund, einen already marks masculine accusative, so großen uses -en.

You do not need to analyse every sentence this way while speaking. The explanation shows why the pattern exists; repeated noun phrases will make the combinations automatic.

Finding the correct ending step by step

Take Ich kaufe ___ warm__ Mantel (“I am buying a warm coat”).

1. Find the noun's gender: der Mantel is masculine.
2. Find its role: it is what is being bought, so it is accusative.
3. Choose the article: masculine accusative is einen.
4. Use the table: the adjective ending is -en.

The result is Ich kaufe einen warmen Mantel.

Now take ___ kalt__ Getränk steht hier (“A cold drink is here”). Getränk is neuter and the subject, so it is nominative: Ein kaltes Getränk steht hier.

Plural forms

German has no plural equivalent of indefinite ein. You cannot say an equivalent of “eins books.” With no article, adjectives follow a different pattern. However, kein and possessives do have plural forms, and after them the adjective takes -en in all four cases:

Case	Example
Nominative	meine alten Freunde
Accusative	meine alten Freunde
Dative	meinen alten Freunden
Genitive	meiner alten Freunde

Notice the extra -n on the dative plural noun Freunden. Most plural nouns add -n in the dative if they do not already end in -n or -s.

More than one adjective

When several adjectives follow the same ein-word, they normally take the same ending:

• ein ruhiges, helles Zimmer
• eine freundliche, hilfsbereite Kollegin
• mit einem langen, schwierigen Gespräch

A comma is used when the adjectives have equal status. Whether a comma is appropriate is a matter of meaning and coordination, but it does not change the declension pattern.

Examples in Context

German	English	Note
Ein großer Mann kommt.	A tall man is coming.	Masculine nominative: -er
Eine junge Ärztin arbeitet hier.	A young doctor works here.	Feminine nominative: -e
Ein kleines Café ist noch geöffnet.	A small café is still open.	Neuter nominative: -es
Ich habe eine neue Tasche.	I have a new bag.	Feminine accusative: -e
Wir suchen einen ruhigen Platz.	We are looking for a quiet place.	Masculine accusative: -en
Sie bestellt ein kaltes Getränk.	She orders a cold drink.	Neuter accusative: -es
Er spricht mit einem alten Freund.	He is talking with an old friend.	Dative after mit: -en
Ich helfe einer neuen Kollegin.	I am helping a new colleague.	Feminine dative: -en
Wir fahren mit unserem kleinen Auto.	We are travelling in our small car.	Possessive, neuter dative
Keine wichtigen Nachrichten sind angekommen.	No important messages have arrived.	Plural nominative: -en
Sie besucht ihre kranken Eltern.	She is visiting her ill parents.	Possessive, plural accusative
Er spielt mit seinen jungen Kindern.	He is playing with his young children.	Dative plural; noun also adds -n
Das ist das Büro eines bekannten Anwalts.	That is the office of a well-known lawyer.	Masculine genitive: -en
Wir brauchen kein teures Hotel.	We do not need an expensive hotel.	kein, neuter accusative: -es

Common Mistakes

Using -e for every adjective

• Wrong: ein große Hund
• Right: ein großer Hund
• Why: Hund is masculine and nominative. Because bare ein has no visible masculine marker, the adjective supplies -er.

Forgetting masculine accusative -en

• Wrong: Ich sehe einen großer Hund.
• Right: Ich sehe einen großen Hund.
• Why: The direct object is masculine accusative. Einen already marks that form, and the adjective takes -en.

Treating neuter nouns like masculine nouns

• Wrong: ein neuer Auto
• Right: ein neues Auto
• Why: Auto is neuter (das Auto), so nominative and accusative after ein use adjective ending -es.

Copying the definite-article pattern blindly

• Wrong: ein kleine Kind
• Right: ein kleines Kind
• Why: After das, you say das kleine Kind, because das clearly marks neuter. Bare ein does not, so the adjective must show neuter with -es.

Inventing a plural form of ein

• Wrong: eine neue Bücher
• Right: neue Bücher or meine neuen Bücher
• Why: German has no plural indefinite article. With no article, the adjective uses the no-article pattern; after a possessive, it uses mixed declension with -en.

Missing the dative plural noun ending

• Wrong: mit meinen alten Freunde
• Right: mit meinen alten Freunden
• Why: The adjective correctly has -en, but the plural noun usually also adds -n in the dative.

Usage Notes

The same endings apply in careful writing and everyday conversation. Spoken German may simplify sentence structure, but standard speakers do not generally drop adjective endings. A wrong ending is often understandable, yet it remains noticeable because the article–adjective combination is a basic part of German grammar.

English “some” does not map neatly onto one German article. Depending on the meaning, German may use no article (Ich kaufe frisches Brot), ein with a singular count noun (Ich kaufe ein frisches Brot), or words such as etwas. Do not automatically choose an ein-word just because an English translation has an article or quantity word.

Possessives agree with the following noun, not with the owner. Seine neue Tasche has feminine -e because Tasche is feminine; sein neues Fahrrad has neuter -es because Fahrrad is neuter. The identity or gender of the person who owns it does not determine the adjective ending.

Beyond the Basics / Advanced Use

You do not need to master every detail at A2, but the same system continues into more advanced German.

The genitive after ein-words consistently uses adjective -en: wegen eines technischen Problems, trotz einer langen Diskussion. Masculine and neuter nouns often also carry -(e)s: eines alten Hauses, meines neuen Computers. In everyday speech, some genitive constructions are replaced by dative or von, but the genitive remains standard and common in formal prose.

A few determiner-like words require closer attention. Manch, solch, and welch can appear in more than one construction, and their adjective endings depend on whether they themselves carry an ending: compare solch ein schöner Tag with ein solcher schöner Tag. These are best learned as separate patterns later rather than forced into the basic ein-word rule.

Nominalized adjectives—adjectives used as nouns—keep the same endings and are capitalized: ein Deutscher (“a German man”), eine Bekannte (“a female acquaintance”), mit einem Kranken (“with a sick person”). The ending still reflects gender, number, and case even though no separate noun follows.

Finally, adjective declension changes when there is no article. Compare ein heißer Kaffee with heißer Kaffee. In the second phrase the adjective alone must carry the grammatical markers. That strong, no-article system is a related later topic, not an exception to the rule taught here.

Practice Tips

1. Learn noun phrases, not isolated endings. Say sets aloud: ein guter Film – einen guten Film – mit einem guten Film. This ties case to a phrase you can actually use.
2. Use the five-cell shortcut. Memorize -er, -e, -es in nominative, then feminine -e and neuter -es in accusative. Treat all remaining cells as -en.
3. Transform one sentence at a time. Start with Ein neuer Kollege kommt, then change its role: Ich treffe einen neuen Kollegen and Ich spreche mit einem neuen Kollegen. Include the article, adjective, and noun in every answer.

Related Concepts

• Prerequisite: Adjective Declension with Definite Articles — compare the mostly weak endings after der, die, das with the mixed endings here.
• Next step: Adjective Declension without Articles — learn how adjectives carry the main gender and case markers when no article is present.