Turkish Vowel Harmony Calculator

How to use the calculator

Type a noun in its dictionary form — kitap, not kitabı — and the tool builds every common form at once: the plural, the seven cases in singular and plural, and the six possessive forms with the locative and accusative added. Capital letters are lowercased the Turkish way, so KAPI becomes kapı (dotless ı) and İNEK becomes inek. For a city, a person or a brand, switch on Proper noun so the suffixes are written after an apostrophe. Each rule that changes the word is listed under the tables with a link to the full explanation in the grammar handbook.

Vowel harmony: the two suffix patterns

Every Turkish suffix contains a vowel that copies the last vowel of the word. 2-way suffixes choose between a and e: back vowels (a, ı, o, u) take a and front vowels (e, i, ö, ü) take e, which is why it is kitaplar but evler. 4-way suffixes also look at lip rounding and choose between ı, i, u, ü: kızı, evi, okulu, gözü. The plural, dative, locative and ablative are 2-way; the accusative, genitive and possessives are 4-way. See vowel harmony rules for the full chart.

Consonants at the boundary

Two changes happen where a word meets a suffix. Hardening: after the voiceless consonants f, s, t, k, ç, ş, h, p (remember them as fıstıkçı şahap) a suffix-initial d becomes t, so kitapta and sütten. Softening: a final p, ç, t, k becomes b, c, d, ğ before a vowel, so kitap → kitabı, ağaç → ağacı, çocuk → çocuğu. Softening is the rule for longer words but most one-syllable words resist it (topu, saçı, sütü), apart from a known list such as renk → rengi and kurt → kurdu. The Ketçap rule guide covers both.

Buffer letters

Turkish avoids two vowels in a row, so when a vowel-final word meets a vowel-initial suffix a buffer consonant is inserted: y in the accusative, dative and instrumental (kapıyı, kapıya, kapıyla), n in the genitive (kapının) and s in the 3rd-person possessive (kapısı). After a 3rd-person possessive, case endings also take an n: arabasında, evini. Read more in buffer letters explained.

Exceptions the tool knows

Some two-syllable nouns drop their last vowel before a vowel suffix (şehir → şehri, ağız → ağzı, oğul → oğlu). Arabic loanwords like hak and his double their final consonant (hakkı, hissi). A group of loanwords keeps front harmony despite a back vowel (saatler, rolü, kalbi), and su uses y everywhere (suyu, suyun). Abbreviations without vowels are read by their letter names, so TL (te-le) gives TL'ye. For how each case is used in sentences, start with the noun cases guide, then the pages on the accusative, dative, locative, ablative and genitive.