Instrumental Case in Polish

Overview

The instrumental case expresses the means or instrument by which an action is performed, and it serves as the predicate case after the verb być (to be). At the A2 level, these two functions make the instrumental one of the most frequently needed cases. It answers the questions kim? (with/by whom?) and czym? (with/by what?).

The instrumental is also required after several common prepositions: z (with), za (behind), między (between), nad (above), and pod (under). This makes it essential for describing locations, companionship, and spatial relationships.

One of the most distinctive uses of the instrumental is after być for professions, nationalities, and roles: Jestem lekarzem (I am a doctor). This is mandatory in Polish and is one of the first grammar rules that surprises English speakers.

How It Works

Instrumental singular endings

Gender	Ending	Example
Masculine	-em	bratem (with brother), domem (with house)
Feminine (-a)	-ą	kobietą (with woman), siostrą (with sister)
Neuter	-em	dzieckiem (with child), miastem (with city)

Instrumental plural endings

Gender	Ending	Example
All genders	-ami	domami, kobietami, dziećmi*

*Some nouns have irregular plural instrumental forms.

Instrumental triggers

Usage	Example
Means/tool	Piszę długopisem. (I write with a pen.)
After być (predicate)	Jestem lekarzem. (I am a doctor.)
With z (with)	Idę z bratem. (I go with brother.)
With za (behind)	za domem (behind the house)
With między (between)	między domem a szkołą
With nad (above)	nad morzem (by the sea)
With pod (under)	pod stołem (under the table)

Examples in Context

Polish	English	Note
Piszę długopisem.	I write with a pen.	Means/instrument
Jestem lekarzem.	I am a doctor.	Predicate after być
Idę z bratem.	I'm going with brother.	Companionship
między domem a szkołą	between home and school	Spatial
Kawa z mlekiem.	Coffee with milk.	z + instrumental
Ona jest nauczycielką.	She is a teacher.	Feminine predicate
Jadę samochodem.	I'm going by car.	Means of transport
pod stołem	under the table	pod + instrumental
nad morzem	by the sea	nad + instrumental
z rodziną	with family	z + instrumental

Common Mistakes

Forgetting instrumental after być

• Wrong: Jestem lekarz.
• Right: Jestem lekarzem.
• Why: The predicate noun after być must be in the instrumental case. This is one of the most consistent rules in Polish.

Using wrong ending for feminine

• Wrong: z kobietem
• Right: z kobietą
• Why: Feminine instrumental singular uses -ą, not -em. -em is for masculine and neuter.

Confusing z + instrumental (with) and z + genitive (from)

• Wrong: Using the same case after z regardless of meaning.
• Right: z bratem (with brother, instrumental) vs. z Polski (from Poland, genitive).
• Why: Z has two meanings with different case requirements. "With" takes instrumental; "from" takes genitive.

Usage Notes

The instrumental is used identically across all registers. In formal writing, the instrumental after być is never optional. The prepositions z, za, między, nad, pod always require instrumental when indicating static location. When indicating direction, some take accusative instead (e.g., za + acc = "in [time]" or "for [exchange]").

Practice Tips

1. Practice describing yourself and others using być + instrumental: Jestem studentem/studentką. On jest lekarzem. Ona jest nauczycielką.
2. Describe how you do things using instrumental for tools and means: Piszę długopisem. Jem widelcem. Jadę autobusem.
3. Practice z + instrumental for companionship: z mamą, z bratem, z przyjacielem, z rodziną.

Related Concepts

• Prerequisite: Case System Introduction -- understanding the case system