By definition there is no legal middle names here in Finland (all of the 1 to 4 names given to you are called "first name" in the law). And thus all of your names will be in the passport too.

Filling some foreign (or poorly done/ported local) it system forms can be bit of a guess work.

Also as a bonus space " " is a legal character in a name. Both "Jukka Pekka" and "Jukka-Pekka" are valid names (also you could have 2 names "Jukka" and "Pekka")

> "Jukka Pekka" [...] also you could have 2 names "Jukka" and "Pekka"

How is that distinguished in legal documents/while registering the name/...?

In most important official documents name is not the only identifier as you also add the national identification number. I guess in most other use cases you just trust humans to get it right.

As for how to register such a name correctly for a baby I have no clue. Also you don't have to give the baby a name at birth (you have 60 days) but the national identification number is given to the baby at birth (it is just date of birth, sequence number and a checksum character). All I know is that I have a colleague which such a name and have seen people before with space instead of - on a 2 part name

edit: How we usually do forms for this stuff is just 2 fields. One for all of your first names and the second for your family name(s) (you can have multiple for example both of your parents or some foreign with de/von/etc). Validation is mostly "check that they are not empty"

Ah, it's so interesting to contrast different approaches.

For example, in Latvia, the legal treatment is that if you have two first names (two is the legal limit) then they are space delimited and if you have two surnames (it's becoming popular to join the surnames after marriage instead of changing the surname of one spouse) then they are hyphenated.

So if you see "Alpha Beta Gamma" then that means Alpha and Beta as given names and Gamma as the surname; and "Alpha Beta-Gamma" means that Alpha is the given name and Beta-Gamma is the surname, so the name in any official documents can be unambiguously parsed.

> "all of the 1 to 4 names given to you are called "first name" in the law"

Is 4 a hard maximum? Because in Dutch it's not unheard of to have more. Not common (most people have 1 or 2), but at least one famous politician had 5 first names.

Current law only allows 4 but allows exception for foreigners (but then the name has to fulfill that other countries naming conventions). Though there is a superseding law that roughly says "the name must not intentionally bring harm to the child" meaning they can block you from giving weird/stupid name to a child (so name like Elon Musks youngest "X Æ A-12" would never be allowed to be given to a baby here)

I have three first names, and round these parts they are space separated. Turns out that in a neighbouring country I should be comma separating them, or they are treated as a single first name (that happens to have spaces).