Translation guide
The English word 'whichever' is used to refer to any one of a limited set of options, or to say that it doesn't matter which one. In Japanese, this concept is expressed through several different structures depending on whether you are offering a choice, describing a free selection, or emphasizing that any option is fine.
Expressing that any one of a specific set of options is acceptable, or that the choice doesn't matter.
Used when choosing between two items. Literally 'either is fine'. Very common and natural.
Whichever is fine.
Please choose whichever you like.
Used when choosing among three or more items. 'Any one is fine'.
Take whichever you like.
Casual version of どちらでも, used in spoken Japanese for two options.
Whichever is fine. (casual)
Formal/literary equivalent of どれでも or どちらでも. Used in writing or formal speech.
Whichever is fine. (formal)
Emphasizing that the result is the same regardless of the choice.
'Whichever way it is' or 'either way'. Used when the outcome doesn't change based on the choice.
Whichever it is, the result is the same.
For three or more options. 'No matter which one'.
Whichever one it is, there's not much difference.
Casual version of どちらにしても.
Whichever it is, I'm not going.
Referring to a specific but unknown item from a set, often followed by a noun.
Used before a noun to mean 'whichever [noun]'. どちら is for two items.
We can adopt whichever proposal.
For three or more items. 'Whichever [noun]'.
You can borrow whichever book.
Formal version of どの〜でも or どちらの〜でも.
Whichever method is fine.
Use どちらでも for two options (polite/neutral), どっちでも for two options (casual), and どれでも for three or more options. どちら is the polite form of どっち, but both are common in everyday speech depending on formality.
English 'whichever' often corresponds to these question-word + でも patterns. Do not try to translate 'whichever' as a single word; it will sound unnatural.
どれでも構いません。
Whichever is fine. (polite)