"Congrats" is just an informal and shortened version of the plural noun "congratulations". Both have the same meaning and are commonly used. However, "congratulations" is definitively more formal.

"Congrats" is just an informal and shortened version of the plural noun "congratulations". Both have the same meaning and are commonly used. However, "congrats" is definitively more informal.

Congrats on your recent promotion!

We offered our sincere congratulations to Olivia Smith on being elected.

Generally, "congratulations" sounds better if the context is not clearly informal.

Congratulations on your achievement!

You can use "congrats" in casual conversations, like texting, chatting, or writing short messages.

Congrats on your new venture!

On the other hand, "congrats" is almost always an interjection; it mainly expresses feeling rather than meaning.

Congrats on your new baby girl!

Congratulation can be an interjection or a noun.

Congratulations! (Interjection)

Please send him my congratulations. (Noun)

"Congratulations" is a plural noun. The singular form (congratulation), is the act of congratulating someone.

I sent her a note of congratulation.

While we typically say "congratulations on", the preposition "for" can be used in some situations. Be also aware that the correct spelling of this word is "congratulations" (not "congradulations").