The illative case (illatiivi, often just called “the mihin form”, more recently also “S-mihin“) is generally used to express movement towards something. If you’re looking for an overview about missä, mistä and mihin, look here.

1. Terminology problem: Mihin or S-mihin

Terminology issue: “illative” is the linguistic term for the form that means “to” or “into”. If you’re studying Finnish in Finland on a course for immigrants, you will most likely not hear the grammatical term. Instead, your teachers are more likely to use the terms mihin–muoto and S-mihin.

The S in S-mihin makes sense when you take into account that Finnish has 6 location-related cases:

Looking at the third column, you can see koulussa, koulusta and kouluun. The fifth column has kurssilla, kurssilta and kurssille. Both kouluun and kurssille are suitable ways to answer the question “Mihin?”. Most Finnish courses and textbooks will not use grammatical names for the cases. It’s considered unnecessary to use space in your brain for these random case names.

Because of this, talking about “mihin-muoto” and “S-mihin” is a good solution. Older textbooks will refer to the illative case as “mihin-muoto“, while newer ones use the term “S-mihin”. The S helps use differentiate between the illative and the allative cases. The illative case itself only includes an “s” in some verb specific wordtypes (e.g. huone → huoneeseen) but it’s part of the inner location case system, where the “missä-muoto” has -ssa/ssä (rather than -lla/ltä) and the “mistä-muoto” has -sta/stä (rather than -lta/ltä).

To learn more about missä, mistä and mihin and their usage, look here.

2. The Use of the Illative Case (Mihin, S-mihin)

2.1. When saying TO or INTO

The illative case has several different-looking endings (see section 3 below), but the meaning is usually quite clear: it means a movement into something or towards something or somewhere. In English you usually use “to” or “into”.

There can be some confusion with the allative, which also is translated as “to” in some cases. In general, the illative can be translated as “into”, while the allative is translated as “onto”. However, both will often be translated as “to”.

2.2. When talking about time (until)

The illative case is used to express until when something lasts.

2.3. Rections with the mihin form

This section is for intermediate students. In Finnish, certain words will “require the mihin form”. This is the typical way to describe that certain words will always be accompanied by a word in the mihin-form. We call this phenomenon a “rection“.

Some words require the mihin-form. This can be the case with both nouns and verbs:

2.3.1. Verbs + Noun in the S-mihin form

There are several verbs that require the S-mihin. Some common examples are tutustua (to get to know), rakastua (to fall in love) and tottua (to get used to).

• You can learn more about verb rections.
• You can also read more about verbs that answer the question keneen.

2.3.2. Verbs + Verb in the –maan form

Verbs can also be inflected in the mihin-form.  The examples below all utilize the -maan form of the verb.

• You can read more about the third infinitive (-maan, -massa, -masta).
• You can also learn more about third infinitive rections.

2.3.3. Verbs + Verb in the –miseen form

Verbs can also be inflected in the mihin-form by making them into nouns first. For example uiminen “swimming” is a noun derived from the verb uida “to swim”. However, note that in English, both uimaan (section 2.3.2) and uimiseen (this section) can be translated as “swimming”.

As such, translating directly isn’t helpful at all. It’s all tied to which verb you’re using. You need to look at the verb used in the sentence to know which version should be used. For example, keskittyä and kyllästyä require the –miseen form of verbs.

• Find out more about fourth infinitive verb rection verbs here!
• Read more about the fourth infinitive in general.

2.3.4. Adjectives + Noun in the S-mihin form

Adjectives can also have rections: they can require the word attached to them to appear in the mihin form. In addition to the examples below, you can also read more in the article about adjective rections.

2.3.5 Noun + Noun in the mihin form

Certain nouns also require the mihin-form of the word connected to them.

• Read more about noun + noun rections!

3. The Formation of the Illative Case

The illative is one of the six location cases. It’s different from the other location cases for at least two reasons. Firstly, it’s added to the strong form of the word (learn more about consonant gradation for wordtype A here and for wordtype B here). Secondly, the illative has several different endings, depending on the type of word you’re dealing with.

3.1. Words ending in a single vowel (-a/-ä, -u/-y, -o/-ö): double vowel and add -n

3.2. Words ending in two different vowels: double the last vowel and add -n

3.3. Words of one syllable ending in two vowels: add h + vowel + n

This rule also is used for compound words such as keskiyö (keskiyöhön), ylityö (ylityöhön) and rakennusmaa (rakennusmaahan).

3.4. Words ending in two of the same vowel: add -seen

3.5. Words ending in -e: add another -e- and then -seen

3.6. Words ending in -i

I have a separate article all about the difference between old and new words ending in -i. You could check that out after you’ve looked at the examples on this page!

3.6.1. New words ending in -i: double the last vowel and add -n

New words are often loanwords. Usually they’re recognisable because they resemble words in other languages, like pankki for “bank”, or paperi for “paper”. Loanwords are easier than Finnish words because they don’t undergo as many changes when you add endings.

3.6.2. Old words ending in -i: replace -i with -e-, double that vowel and add -n

Old words are very often nature words. After all, nature has been around for so long that Finns have had names for them since the very beginning. Some words’ age can be confusing, for example “äiti” (mother) is actually a new Finnish word, eventhough mothers have been around since the beginning of time!

This section combines words belonging to the OVI-type, the PIENI-type and the TOIMI-type into one because these types undergo the exact same change when inflected in the illative case.

3.6.3. Old words ending in -si: replace -si with -te-, double the last vowel and add -n

More old words, but this time with -si at their end. This group has its own additional change

I have a more extensive list of words that belong to this type here.

3.7. Words ending in a consonant

3.7.1. Words ending in -nen: replace the -nen with -se- and add -en

3.7.2. Words ending in -as: replace -as with -aa- and add -seen

Words ending in -as (or –äs, depending on vowel harmony rules) belong to wordtype B, so they will have the weak grade in their basic form (e.g. rakas, opas) and the strong grade in the illative (e.g. rakkaaseen, oppaaseen). Read more about words ending in -as here.

3.7.3. Words ending in -is: two groups

For words ending in -is, we have two groups. Words like kallis get -ii- when inflected, to which we add -seen. Words like roskis which get -ikse- when inflected, to which we add -en.

3.7.4. Words ending in -us/-os: two groups

Words ending in -os will get -okse- when inflected. Words ending in -us can belong to two groups: some get -ukse-, others get -ute-. You will want to check out this article to get the specifics.

Some general guidelines:

• If the word is based on a verb (such as opettaa > opetus), it will generally get –ukse-.
• If the word is based on an adjective (such as pimeä > pimeys), it will get –ute-.
• If the word is based on a noun (such as ystävä > ystävyys), it will get –ute-.
• If the word ends in –uus/yys (double vowel), you will get –ute-.

3.7.5. Words ending in -ton: replace with -ttoma- and add -an

Read more about words ending in -ton here.

3.7.6. Words ending in –in: replace with -ime- and add –en

Read more about words ending in -in here.

3.7.7. Words ending in –ut: two groups

Words that end in -ut/yt can belong to two wordtypes. The smallest group of the two contains words such as olut, kevyt and lyhyt. For these words, you will replace the final -t with an –e- and then add -en.

The much larger group is made up of NUT-participles such as väsynyt and tottunut. For the words, you will replace the -ut/yt with -ee- before the illative’s case ending -seen.

3.7.8. Words ending in -tar

Words ending in -tar are rare, but at least tytär (daughter) is a common word. In the mihin-form, these words get -ttare- in place of the basic form’s -tar.

3.7.9. Non-Finnish words ending in a consonant

Loanwords and foreign names (e.g. Jonathan, Facebook) which end in a consonant will get -iin when inflected in the illative case.

You might also want to check out these two articles:

3. Consonant Gradation in the Illative Case

The mihin-form is strong in both wordtype A and wordtype B!

I have a separate article on wordtype A.

I have a separate article on wordtype B.

Related posts:

Location Case Verb Rections – Rektiot Missä Mistä Mihin The Ablative Case (Miltä) – Finnish Grammar The Inflection of Postpositions – Finnish Grammar Adverbs of Location: Täällä, Kaikkialla, Ylhäällä