Open any good Finnish dictionary and you'll find a small number after each noun. That number is its declension type — a code that tells you exactly how the word builds its stem, whether it gradates, and what its partitive looks like. The standard reference, the Kielitoimiston sanakirja (KOTUS classification), sorts every nominal into types 1–51 (the last two being combinations) and every verb into types 52–78. You do not need to memorize the numbers. What pays off is recognizing the roughly dozen big patterns they encode, each named after a model word — valo, nainen, vesi, vieras. This page is that map: one place to look up the genitive, partitive, and stem for each major class.
Why the nominative can't be trusted
The reason a numbered system exists at all is that the dictionary form does not predict the stem. Two nouns can end identically and belong to completely different classes. This is the single most important idea on the page, so meet it head-on before the table:
- lasi (glass) and vesi (water) both end in -si, but lasi is a plain vowel stem (lasin, lasia) while vesi alternates (veden, vettä).
- vastaus (answer) and rakkaus (love) both end in -us, but vastaus builds its stem with -kse- (vastauksen) and rakkaus — actually spelled -uus — builds it with -ude- (rakkauden).
Kaadoin lasiin vettä, mutta lasi oli jo täynnä.
I poured water into the glass, but the glass was already full.
The pair lasiin (into the glass, vowel stem lasi-) versus vettä (partitive of vesi, stem vete-/vede-) inside one sentence shows why look-alike endings must be learned by type, not by eye.
The reference table
Each row gives the nominative → genitive → partitive and the stem you attach other endings to. Learn a noun with at least its genitive and partitive and you have effectively identified its type.
| Type (model) | Nominative | Genitive | Partitive | Stem | Notes |
|---|---|---|---|---|---|
| valo / talo | talo (house) | talon | taloa | talo- | plain vowel stem; gradation if k/p/t (katto → katon) |
| kala / koira | koira (dog) | koiran | koiraa | koira- | a-stem; partitive -a doubles the final vowel |
| kylä | kylä (village) | kylän | kylää | kylä- | front-vowel vowel stem; endings in ä/ö/y |
| kieli / -e stems | kieli (language) | kielen | kieltä | kiele- | "new -i"; stem in -e-, partitive -tä after consonant |
| nainen | nainen (woman) | naisen | naista | naise- | -nen → -se- stem; very large, regular class |
| vesi / käsi | vesi (water) | veden | vettä | vete- / vede- | -si from old -ti; gemination in partitive (vet+tä); käsi also gradates |
| vieras | vieras (guest) | vieraan | vierasta | vieraa- | -s → long-vowel stem -aa-; partitive keeps the -s |
| vastaus | vastaus (answer) | vastauksen | vastausta | vastaukse- | deverbal -us; stem inserts -kse- |
| rakkaus | rakkaus (love) | rakkauden | rakkautta | rakkaude- | abstract -uus/-yys; stem -ude-, partitive gemination |
| puhelin | puhelin (phone) | puhelimen | puhelinta | puhelime- | -in → -ime- stem (n → m); partitive keeps -n |
That is the working core — roughly the dozen shapes that cover the great majority of Finnish nouns. A few observations turn it from a table into a tool.
Reading the map: where the traps hide
The partitive tells you the class. More reliably than the nominative, the partitive reveals which family a word belongs to. A partitive in -a/-ä points to a vowel stem (taloa, kylää, koiraa); a partitive in -ta/-tä points to a consonant-final or consonant-stem type (naista, vierasta, vastausta, puhelinta); a geminated partitive (vettä, kättä, rakkautta) points to the vesi-type and the -uus abstracts.
Sain kysymykseen selkeän vastauksen jo samana päivänä.
I got a clear answer to the question the very same day.
Vieraat saapuivat ajoissa, ja tarjosimme heille kahvia.
The guests arrived on time, and we offered them coffee.
Gradation lives inside a class, not across it. The talo type only gradates if the stem happens to contain a k/p/t cluster: talo → talon (nothing to gradate) but katto → katon (tt → t) and kukka → kukan (kk → k). The vesi/käsi type carries its own alternation (käsi → käden, t → d). So "does it gradate?" is answered by the individual stem, not by the type label alone.
Kukan lehdet olivat kuihtuneet, mutta katon alla se selvisi talven yli.
The flower's leaves had wilted, but under the roof it survived the winter.
Look-alike endings, different classes. Keep the confusable pairs in mind: -si splits into vowel-stem lasi and alternating vesi; -us splits into deverbal vastaus (-kse-) and abstract -uus (rakkaus, -ude-); -nen is almost always the regular nainen type.
How to use this in practice
When you meet a new noun, don't ask "what's the nominative pattern?" — ask "what are the genitive and partitive?" Those two forms expose the stem and place the word on this map instantly. A dictionary that gives you puhelin, puhelimen, puhelinta has already told you it is the -in class; one that gives rakkaus, rakkauden, rakkautta has told you it is a -uus abstract. This is why every serious Finnish flashcard lists the genitive alongside the headword — the headword alone is the one form that doesn't tell you what you need.
Uuden puhelimen akku kestää helposti koko päivän.
The new phone's battery easily lasts the whole day.
Rakkaus ei katso ikää, sanotaan, mutta kärsivällisyyttä se vaatii.
Love knows no age, they say, but it does demand patience.
Common Mistakes
❌ Kaadoin veteä lasiin.
Incorrect — vesi is the -si/gemination type; its partitive is vettä, not veteä.
✅ Kaadoin vettä lasiin.
I poured water into the glass.
❌ Sain hyvän vastauden.
Incorrect — deverbal vastaus takes -kse-, giving the genitive vastauksen (not the -ude- of rakkaus).
✅ Sain hyvän vastauksen.
I got a good answer.
❌ Kuinka monta kielitä sinä puhut?
Incorrect — kieli is an -e stem; its partitive is kieltä (stem kiele-), not kielitä.
✅ Kuinka monta kieltä sinä puhut?
How many languages do you speak?
❌ Ostin uuden puhelinin.
Incorrect — the -in class builds its stem with -ime-, so the genitive is puhelimen.
✅ Ostin uuden puhelimen.
I bought a new phone.
Key Takeaways
- The dictionary tags each noun with a type number (nominals 1–51); you need the model words, not the numbers.
- The nominative does not predict the stem — lasi vs vesi, vastaus vs rakkaus look alike but belong to different classes.
- The partitive is the best clue: -a/-ä = vowel stem, -ta/-tä = consonant type, geminated (vettä, rakkautta) = vesi/-uus type.
- Gradation is a stem property, not a class property: talo → talon but katto → katon.
- Learn every noun with its genitive and partitive, and this map places it at a glance.
Now practice Finnish
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Start learning Finnish→Related Topics
- Vowel StemsA2 — The easy majority: nouns whose inflectional stem is just the dictionary form with its final vowel kept — talo→talossa, kylä→kylässä — endings attach directly.
- The -e Stems: kieli → kiele-B1 — A large, deceptive class: nouns ending in -i that inflect on an -e- stem (kieli→kielen, ovi→oven), unlike loanwords in -i that keep the -i (pankki→pankin).
- The -s : -kse / -hte Nouns (vieras, kaunis)C1 — The high-frequency -s class whose stem lengthens the vowel: vieras→vieraa- (vieraan, vierasta), kaunis→kaunii-, rakas→rakkaa- (inverse gradation).
- -us / -ys Nouns: vastaus → vastaukse-B1 — Deverbal nouns in -us/-ys hide an -ukse-/-ykse- stem: vastaus → vastauksen, vastausta. How to tell them from the -uus abstracts.
- -uus / -yys Nouns: rakkaus → rakkaude-B1 — Abstract quality nouns in -uus/-yys hide an -uude-/-yyde- stem: kauneus → kauneuden, kauneutta. How they differ from the -ukse- nouns.