How informal should supplamentamental/common app answers be?

I ave been looking through several of my Common App responses and they all appear to be rather informal. Normally when I write a paper for school I tend to use an “academic” style, using words/phrases like “thus,” “in that,” “through which.” Despite this, in my Common App questions I tend to write more informally, using words/phrases like “so many,” “because of,” “gets interesting.”

It sounds natural and is definitely my voice but I am somewhat concerned that I should be more formal. I think an essay grade online said it was 11-12th grade level when normally my papers are at a college level.

Should I try and be more “formal/academic” or is that the wrong approach? Any ideas?

How informal can I be?

Informal but approriate is good.

I think that being somewhat informal is fine, especially if your essay creates a distinct tone/voice from the conversational choice of language. Writing a huge formal academic essay will make you seem like a stiff unless its extremely well-done and compatible with the rest of your app, otherwise, schools want to see in an essay that your personality and views come through. As long as your language doesnt tread into slang, vulgarity, or otherwise, being conversational with “gets interesting” is fine.