Russian ordinal numbers: first, second, third (первый, второй, третий)

Мы живём на третьем этаже. Это моя вторая книга. Сегодня пятый день курса.We live on the third floor. This is my second book. Today is the fifth day of the course.

An ordinal number says the place in an order (first, second, third). In Russian it answers какой? and, for a place in a series, который? (Который по счёту?, "Which one in the count?"). The cardinal numbers are in Cardinal numbers 1–20 and Cardinal numbers 20–1000. Ordinals look like numbers but behave like adjectives: they agree with the noun in gender, number and case, so Adjective declension through the cases applies to them as well.

In short: an ordinal is an adjective that is built from a number: первый, второй, третий, четвёртый, пятый…. It takes the ending of the noun's gender and case (первый урок, первая страница, первое слово). With a compound number only the last word is an ordinal: двадцать первый.

The ordinals from 1 to 20

The first ten ordinals are separate words and have to be learned one by one. The masculine form is the dictionary form; most neuter and feminine forms are regular (третий is the one soft-stem exception, see below):

The ordinals from 11 to 20 are formed from the cardinal by dropping the final soft sign and adding -ый: одиннадцать → одиннадцатый. They then have the same neuter and feminine forms as пятый (одиннадцатое, одиннадцатая):

Several masculine forms end in a stressed -ой instead of -ый: второй, шестой, седьмой, восьмой (and later сороковой). Their neuter and feminine forms are regular (шестое, шестая). The ordinal третий is the only one with a soft stem; see the declension below.

Tens, hundreds and larger numbers

The ordinals for the tens end in -ый, except сороковой. The numbers 50–80 begin with the genitive form of the cardinal (пяти-, шести-), and 40, 90 and 100 have their own stems:

Round hundreds and thousands are one word as well (двухсотый "200th", пятисотый "500th", двухтысячный "2000th"), but you will need them rarely. For everyday use, the ordinals up to 100 are enough.

Compound numbers: only the last word changes

In a compound ordinal, only the last word is an ordinal; the words before it stay cardinal numbers and do not change:

• двадцать первый век (the twenty-first century)
• сто двадцать третья страница (page 123)
• две тысячи двадцать пятый год (the year 2025)

Declension

Ordinals decline like adjectives, as described in Adjective declension through the cases. A hard-stem ordinal such as первый (and второй, пятый, седьмой and the others) is declined like новый. The accusative masculine is the nominative with an inanimate noun and the genitive with an animate noun:

The ordinal третий is a soft-stem adjective, with endings spelled -ий, -ья, -ье, -ьего (третий, третья, третье, третьего):

In the plural the same forms serve all genders: первые, вторые, третьи; genitive первых, третьих; dative первым, третьим; instrumental первыми, третьими; prepositional первых, третьих. The accusative plural follows the same animate and inanimate rule.

Using ordinals

An ordinal agrees with the noun it describes, so look at the noun's gender, number and case:

• Я живу на пятом этаже. (I live on the fifth floor.)
• Мы сидим в седьмом ряду. (We sit in the seventh row.)
• Это мой первый урок. (This is my first lesson.)
• Я здесь в первый раз. (I am here for the first time.)

A cardinal number after the word номер labels something, while an ordinal counts a position and usually comes before the noun:

• дом номер пять (house number five)
• пятый дом по улице (the fifth house along the street)

In digits, ordinals are written with a hyphen and an ending: 5-й этаж, на 5-м этаже, 21-й век. For dates, Russian uses the neuter ordinal (пятое мая); they are covered in Time expressions: days and dates.

Common mistakes

• ❌ третый этаж → ✅ третий этаж (The ordinal third is soft: третий)
• ❌ двадцатый пятый → ✅ двадцать пятый (In a compound ordinal, only the last word is an ordinal)
• ❌ сорокый → ✅ сороковой (The ordinal for 40 is сороковой)
• ❌ на пять этаже → ✅ на пятом этаже (The ordinal agrees in case with the noun: на … этаже takes the prepositional)
• ❌ первая урок → ✅ первый урок (The ordinal agrees in gender with the noun: урок is masculine)
• ❌ в первое раз → ✅ в первый раз (The word раз is masculine: в первый раз)

Quick check

Which form of the ordinal fits each gap?

1. Я живу на ____ этаже. (5)
2. Это моя ____ книга. (2)
3. ____ урок (3)
4. двадцать ____ день (5)
5. ____ слово (1)
6. Мы сидим в ____ ряду. (7)

Key takeaways

• Ordinals are adjectives: первый / первое / первая agree with the noun in gender, number and case.
• The first ten are separate words (первый, второй, третий…), and 11–20 end in -надцатый; второй, шестой, седьмой, восьмой end in a stressed -ой.
• The ordinal третий has a soft stem (третьего, третьей).
• With compound numbers only the last word is an ordinal: двадцать первый, сто двадцать третья.
• Write ordinals in digits with a hyphen and an ending: 5-й этаж.
• Learn the special forms сороковой (40), девяностый (90) and сотый (100).