Instrumental case
A1 Narzędnik 10 / 52
In short
The instrumental (Polish narzędnik) is the case you use to say what something is after the verb być (to be) - Jestem studentem (I am a student) - and to say by what means you do something - piszę długopisem (I write with a pen). Its name comes from narzędzie (a tool), and that is a good hint: it answers kim? (as whom?) and czym? (with/by what?). For a beginner it matters most because Polish does not keep the noun in its dictionary form after być: you must change the ending.
The rule
The instrumental has three everyday jobs at A1 level.
1. The predicate after być (jestem studentem)
When być links a subject to a noun that names or classifies it (profession, nationality, role, identity), that noun goes into the instrumental, not the nominative:
- Jestem nauczycielem. - I am a teacher.
- Ona jest lekarką. - She is a doctor.
- Oni są studentami. - They are students.
This is different from English, where the noun does not change (“I am a student”), and different from the nominative you learned in To jest student. Compare the two Polish patterns carefully:
- To jest / To są + nominative - pointing at / identifying: To jest student. (This is a student.)
- subject + być + instrumental - saying what the subject is: On jest studentem. (He is a student.)
One important limit: if the predicate is only an adjective, it stays in the nominative, agreeing with the subject - Jestem młody (I am young), Ona jest miła (She is nice). The instrumental is for the noun. When you have both, the noun is instrumental and any adjective with it also becomes instrumental: Jestem dobrym studentem (I am a good student).
2. The means or instrument (czym?)
Without any preposition, the instrumental says with/by what an action is done:
- Piszę długopisem. - I write with a pen.
- Jem widelcem. - I eat with a fork.
- Jadę autobusem. - I go by bus.
3. After the preposition z (with = together with)
The instrumental is also used after several prepositions; the first one you need is z meaning (together) with somebody or something:
- Idę do kina z bratem. - I am going to the cinema with my brother.
- Kawa z mlekiem. - Coffee with milk.
Other instrumental prepositions - nad (above), pod (under), przed (in front of), za (behind), między (between) - come later, but they all take the same endings.
Forms & patterns
The endings are unusually regular: -em for masculine and neuter singular, -ą for feminine singular, and -ami for (almost) all plurals.
Instrumental singular
| Gender | Ending | Nominative -> Instrumental |
|---|---|---|
| masculine | -em | student -> studentem, kot -> kotem, pan -> panem, nauczyciel -> nauczycielem |
| masculine (stem in k/g) | -iem | Polak -> Polakiem, pociąg -> pociągiem |
| neuter | -em | okno -> oknem, morze -> morzem, dziecko -> dzieckiem |
| feminine (in -a) | -ą | kobieta -> kobietą, książka -> książką, lekarka -> lekarką |
| feminine (soft / in -i) | -ą | pani -> panią, noc -> nocą |
Note the spelling rule: after k and g you write -iem, never plain -em (Polakiem, not Polakem).
Instrumental plural
| Gender | Ending | Nominative pl. -> Instrumental pl. |
|---|---|---|
| all genders (default) | -ami | studenci -> studentami, koty -> kotami, kobiety -> kobietami, okna -> oknami |
A small group of nouns take -mi instead - learn them as fixed items:
| Nominative pl. | Instrumental pl. |
|---|---|
| ludzie (people) | ludźmi |
| dzieci (children) | dziećmi |
| goście (guests) | gośćmi |
| konie (horses) | końmi |
| przyjaciele (friends) | przyjaciółmi |
Adjective agreement in the instrumental
An adjective (or ten, mój) with the noun takes matching instrumental endings:
| Gender/number | Ending | Example |
|---|---|---|
| masc./neuter sg. | -ym / -im | dobrym studentem, polskim autobusem |
| feminine sg. | -ą | dobrą lekarką, moją siostrą |
| plural (all) | -ymi / -imi | dobrymi studentami, polskimi dziećmi |
być + instrumental: the full frame
| Person | być | + instrumental noun |
|---|---|---|
| ja | jestem | studentem / studentką |
| ty | jesteś | lekarzem / lekarką |
| on/ona/ono | jest | Polakiem / Polką |
| my | jesteśmy | nauczycielami |
| wy | jesteście | inżynierami |
| oni/one | są | studentami |
Examples
| Polski | English |
|---|---|
| Jestem studentem na uniwersytecie. | I am a student at the university. |
| Moja mama jest lekarką. | My mum is a doctor. |
| Czy jesteś Polakiem? | Are you Polish (a Pole)? |
| On chce być nauczycielem. | He wants to be a teacher. |
| Piszę list długopisem. | I am writing a letter with a pen. |
| Jedziemy do Krakowa pociągiem. | We are going to Krakow by train. |
| Piję kawę z mlekiem. | I drink coffee with milk. |
| Idę na spacer z psem. | I am going for a walk with the dog. |
| Oni są dobrymi przyjaciółmi. | They are good friends. |
| Rozmawiam z dziećmi. | I am talking with the children. |
Common mistakes
- Jestem student -> Jestem studentem - after być, a predicate noun takes the instrumental, not the nominative.
- Ona jest lekarka -> Ona jest lekarką - feminine nouns in -a become -ą here (lekarka -> lekarką).
- Jadę autobusiem -> jadę autobusem - only stems in k/g take -iem; a plain consonant stem takes -em.
- Polakem -> Polakiem - after k you must write -iem, not -em.
- z ludziami -> z ludźmi - ludzie is one of the irregulars taking -mi (with softening), not -ami.
- Jestem młodym (meaning “I am young”) -> Jestem młody - a predicate that is only an adjective stays nominative; the instrumental is for the noun.
- To jest studentem -> To jest student - the to jest pointing pattern keeps the nominative; use the instrumental only with jestem / jest / są and a subject.
Tips
- Memory hook: narzędnik = “the tool case” - czym? (with what?). Piszę długopisem = writing with a pen.
- Two words, two endings: -em covers masculine and neuter; -ą is the feminine one - the same -ą you hear at the end of ona jest miłą osobą.
- After być, ask “am I saying what someone is (a noun)?” If yes, use the instrumental. If it is just an adjective, keep the nominative.
- Keep To jest student (nominative) apart from On jest studentem (instrumental) - the pointing pattern never changes the ending, the linking pattern always does.
- Spelling reflex: k/g are never followed by -em - it is always -kiem, -giem (Polakiem, pociągiem).
- Learn the -mi irregulars as a short list (ludźmi, dziećmi, gośćmi, końmi, przyjaciółmi); almost everything else is safely -ami.