Finnish consonant gradation explained, with a full table
Why is it kauppa but kaupassa, and katu but kadulla? That is consonant gradation, the regular change of k, p and t inside Finnish words. Here is how it works and when it happens.
4 min read · Updated 10 October 2026
What consonant gradation is
Consonant gradation (astevaihtelu) means that the consonants k, p and t in the last syllables of a word can change when you add an ending. Every such word has a strong grade and a weak grade.
kauppa → kaupassa
shop → in the shop
katu → kadulla
street → on the street
pankki → pankissa
bank → in the bank
ottaa → otan
to take → I take
It looks irregular at first, but it follows clear patterns, and the same patterns work in nouns, adjectives and verbs.
The gradation table
| Strong → weak | Noun example | Verb example |
|---|---|---|
| kk → k | pankki → pankissa, Pekka → Pekan | nukkua → nukun |
| pp → p | kauppa → kaupassa, kuppi → kupin | oppia → opin |
| tt → t | matto → matolla, konsertti → konsertissa | ottaa → otan |
| k → (disappears) | jalka → jalan, joki → joen | lukea → luen |
| p → v | leipä → leivän, kylpy → kylvyn | saapua → saavun |
| t → d | katu → kadulla, pöytä → pöydällä, äiti → äidin | tietää → tiedän |
| nk → ng | Helsinki → Helsingissä, kenkä → kengän | – |
| mp → mm | kampa → kamman, lampi → lammen | ampua → ammun |
| lt → ll | ilta → illalla, kulta → kullan | kieltää → kiellän |
| nt → nn | ranta → rannalla, hinta → hinnan | antaa → annan |
| rt → rr | kerta → kerran, parta → parran | ymmärtää → ymmärrän |
| lk → l / lj | jalka → jalan, jälki → jäljen | kulkea → kuljen |
| ht → hd | Lahti → Lahdessa | lähteä → lähden |
A few smaller patterns grow out of the k → (disappears) rule:
- Between u and u, or y and y, k becomes v: puku → puvun (suit), luku → luvun (number, chapter), kyky → kyvyn (ability).
- After l, r or h before e, k becomes j: jälki → jäljen, kulkea → kuljen, särkeä → särjen (to break, ache).
- In words like aika → ajan (time) and poika → pojan (boy), the k disappears and the i before it is written as j.
Gradation only affects k, p and t, and only after a vowel or after h, l, m, n or r. After s, or in the cluster tk, nothing changes: posti → postissa, lasku → laskun, matka → matkalla.
When does the weak grade appear?
The classic rule: a consonant takes the weak grade when the syllable it starts is closed, that is, when that syllable ends in a consonant. In kau-pas-sa, the syllable pas ends in s, so pp becomes p. In kaup-pa or kaup-paa, the syllable is open, so it stays strong.
In practice, this gives a simple guide for ordinary nouns:
| Strong grade | Weak grade |
|---|---|
| basic form: kauppa, katu, pankki | genitive -n: kaupan, kadun, pankin |
| partitive: kauppaa, katua, pankkia | -ssa, -sta: kaupassa, kadusta |
| illative: kauppaan, katuun, pankkiin | -lla, -lta, -lle: kadulla, pankilta, kaupalle |
| essive -na: kauppana, katuna | translative -ksi: kaupaksi |
| plural partitive: kauppoja, katuja | plural -t: kaupat, kadut, pankit |
Käyn kaupassa.
I'm going to the shop (and back).
Menen kauppaan.
I'm going into the shop.
Asun tällä kadulla.
I live on this street.
Hän on töissä pankissa.
He/she works at a bank.
Ostin leivän.
I bought a loaf of bread.
Pöydällä on leipää.
There is bread on the table.
Gradation in verbs
In type 1 verbs, the weak grade appears in the minä, sinä, me and te forms, and the strong grade in the infinitive and the hän and he forms.
| Person | ottaa (to take) | lukea (to read) | tietää (to know) |
|---|---|---|---|
| minä | otan | luen | tiedän |
| sinä | otat | luet | tiedät |
| hän | ottaa | lukee | tietää |
| me | otamme | luemme | tiedämme |
| te | otatte | luette | tiedätte |
| he | ottavat | lukevat | tietävät |
The past tense follows the same logic: otin (I took) but hän otti (he/she took); luin (I read) but hän luki; nukuin (I slept) but hän nukkui.
Two forms look open but still take the weak grade: the negative form and the sinä command. En ota. (I don't take.) Ota! (Take!) En ymmärrä. (I don't understand.)
Reverse gradation
In some words the basic form has the weak grade and the other forms have the strong one. This happens in nouns ending in -e or -as/-äs, and in verb types 3, 4 and 6.
| Basic form (weak) | Inflected form (strong) | Meaning |
|---|---|---|
| sade | sateen, sateessa | rain |
| liike | liikkeen, liikkeessä | shop, movement |
| osoite | osoitteen | address |
| hammas | hampaan | tooth |
| rikas | rikkaan | rich |
| opas | oppaan | guide |
| tavata | tapaan | to meet / I meet |
| kuunnella | kuuntelen | to listen / I listen |
| hypätä | hyppään | to jump / I jump |
| lämmetä | lämpenee | to get warmer / it gets warmer |
If a noun ends in -e or -as/-äs, or a verb is type 3, 4 or 6, expect the inflected forms to be stronger than the dictionary form.
Words that don't change
Not every k, p or t grades. Besides the clusters st, sk, sp and tk, some common words and many loanwords stay the same: auto → autossa, not audossa. Many first names do grade, so listen for Pekka → Pekan, Antti → Antin, and for place names like Turku → Turussa and Helsinki → Helsingissä.
How to learn gradation without stress
- Learn nouns with their genitive: katu, kadun; kauppa, kaupan. That pair shows the weak grade.
- Learn verbs with their minä form: ottaa, otan; tavata, tapaan.
- Learn the place names you use often: Helsingissä, Turussa, Lahdessa.
- Read a little every day. Your eye starts to expect the right grade.
Gradation runs through the Finnish cases and the verb types, so it gets easier as you learn both.
Practise with Maija
Saying kaupassa, kadulla and otan out loud is the fastest way to make gradation automatic. Maija's spoken classes give you lots of these forms in real sentences, and when you say kauppassa she points out the gradation and explains it in plain words. Take the free level check to begin at your level.
Frequently asked questions
What is consonant gradation in Finnish?+
It is the regular change of k, p and t between a strong and a weak grade when endings are added, for example kauppa → kaupassa, katu → kadulla, ottaa → otan.
When does Finnish use the weak grade?+
Usually when the syllable is closed by the ending: the genitive -n, -ssa, -sta, -lla, -lta, -lle, the plural -t and the minä/sinä/me/te forms of verbs.
Why is it kauppaan and not kaupaan?+
The illative keeps the strong grade, like the partitive and the essive: kauppaan, kauppaa, kauppana.
What is reverse consonant gradation?+
In some words the basic form is weak and the other forms are strong, for example sade → sateen, rikas → rikkaan, tavata → tapaan.