The instrumental marks a noun used as a tool or instrument, and by extension almost anything following the preposition с (with). Answers кем? / чем? (with whom? / with what?). Two uses cover roughly 95% of it: tool, and “with”.
The two uses, and the preposition trap
- As a tool / instrument - I cut bread with a knife, I write with a pen. The knife and pen go in the instrumental. Crucially, when a noun is a genuine tool, Russian uses no preposition - the instrumental ending alone means “with (this tool)”. Я режу хлеб ножом (ножом already means “with a knife”); saying с ножом here is wrong.
- After the preposition с (with) - for accompaniment or ingredients, even when nothing is a tool: чай с сахаром (tea with sugar), кофе с молоком (coffee with milk), гулять с собакой (walk with the dog), говорить с другом (talk with a friend). Here you keep с and still put the noun in the instrumental.
So the test: real tool → instrumental, no preposition. “With” something → с + instrumental.
Singular endings
Masculine and neuter take -ом (-ем after a hissing consonant); feminine takes -ой (-ей after a hissing consonant).
| Gender | Nominative | Instrumental | Meaning |
|---|---|---|---|
| Masc | сахар | сахаром | with sugar |
| Masc | друг | другом | with a friend |
| Masc (name) | Иван | Иваном | with Ivan |
| Masc (tool) | нож | ножом | with a knife |
| Masc (hissing) | муж | мужем | with the husband |
| Neut | молоко | молоком | with milk |
| Neut | масло | маслом | with butter |
| Fem | собака | собакой | with the dog |
| Fem (name) | Марина | Мариной | with Marina |
| Fem (tool) | ручка | ручкой | with a pen |
| Fem (tool) | ложка | ложкой | with a spoon |
| Fem (hissing) | Наташа | Наташей | with Natasha |
Names without a clear gender ending do not decline (Джошуа, Дженнифер).
Examples
- Я пью чай с сахаром - I drink tea with sugar (accompaniment, keep с).
- Я говорю с другом - I am talking with a friend.
- Я режу хлеб ножом - I cut bread with a knife (tool, no с).
- Я ем курицу вилкой - I eat chicken with a fork (tool, no с; курицу is the accusative object).
- Я гуляю с собакой - I am walking with the dog.
Beyond tool and “with”
From the overview, the instrumental also appears with:
- Professions and becoming - хочу стать учителем (I want to become a teacher), быть + instrumental.
- Certain verbs - гордиться (be proud of), интересоваться (be interested in), наслаждаться (enjoy).
A good tactic: memorise a couple of everyday phrases as templates (чай с сахаром, кофе с молоком) and map new nouns onto their endings.
Lessons worth keeping
- Instrumental = tool or “with”. Genuine tool → instrumental with no preposition; accompaniment/ingredient → с + instrumental.
- Endings: masculine/neuter -ом, feminine -ой (soften to -ем/-ей after hissing consonants).
- Never say с + a tool (с ножом for cutting is wrong); the ending alone carries “with”.
- Also used for professions/becoming (стать учителем) and after verbs like гордиться and интересоваться.
Related
- russian-case-system - the overview.
- accusative-case - the direct object that often sits alongside an instrumental tool (ем курицу вилкой).
Sources
- youtube.com/watch?v=9o1ecDwMeYo - Russian Readers, “The Instrumental Case”.
- Full transcript: instrumental-case