My bad or I'm sorry

"I'm sorry" is not considered formal. You can try to soften it up a bit depending on context with something like "sorry about that" but just "sorry" is fine, you can say that to anyone in any context. Formal would be "I apologize".

You can just say "sorry" without the "I'm" in front. Alternatively something like "whoops sorry" or "oops", especially if it was a mistake like bumping into someone.

"I'm sorry" generally is not considered formal. For example, if you wished to express apology via email (which is typically a formal message) you would say, "I apologize for..." or "I apologize profusely..." or more subservient and accepting of fault, "There is no excuse for my actions..." If you want other ways to apologize in casual conversation, "my bad" is typically the most common between friends or colleagues who know each other. You can also use these: \- "My mistake." or "My fault." \- "Beg your pardon." (archaic or old way of talking) \- "Whoops..." (with an upward inflection and maybe stress the S for comedic effect) \- "Well, that sucks..." (comedic) \- A clever joke. My personal favorite: "Well, my plan was calculated, but BOY am I bad at math." Edit: Formatting Edit2: Don't use the lower options if you are not at least on good terms with who you are talking to. My bad/mistake/fault is enough and no one expects more.

Soz. This is totes casual. 😉

"my bad" always feels a bit disingenuous to me

Just “Sorry” is perfectly okay in casual conversation

That’s on me, oops,

I don’t think “I’m sorry,” or just “sorry,” are quite as formal as you imagine. People may use these a dozen times a day in casual, ordinary situations. And of course, there’s nothing wrong with a complete sentence to clarify what you mean… e.g. “Sorry, that was my fault.”

Lots of good replies here. I will second the ode that “I’m sorry,“ is not formal. As such it can’t be - too formal.

my mistake

The Latin phrase "mea culpa" can be used in *some* informal settings. It depends on the culture of the gathering and the nature of the apology (for what and how earnestly felt).

Don’t say my bad.

I’m sorry wouldn’t be considered formal at all. My bad would be too casual for a lot situations but can be ok for quick acknowledgements in certain situations

Just say “sorry.” “My bad” is appropriate with your friends.

A good Homer Simpson "D'oh!" works in a lot of situations

I think the best way to make “I’m sorry” less formal is to just say “sorry”

To me "my bad" is basically saying "I made a mistake", but not actually apologizing, and it's very very casual -- to the point of not being serious. Just say "I'm sorry" as it is polite and the most appropriate phrasing in most instances.

"I'm sorry" is okay for a funeral "I apologize" is not.

“I’m sorry” is not too formal. “My bad” can come across as dismissive. Always default to “I’m sorry” unless the transgression is truly minor *and* you’re talking to a friend. Boss: Why are you late? You: My bad. WRONG! Friend: Why did you fuck my girlfriend? You: My bad. WRONG! Friend: Dude! That was a nasty fart! You: My bad. RIGHT! ETA: Boss: That was a nasty fart! You: My bad. WRONG!

"I'm sorry" isn't too formal. It's absolutely fine, anywhere. "My bad" *is* informal, but it will only make sense in some places. "I'm sorry" is universal. There are a few synonyms; "Oops", "my apologies", "my mistake", "butterfingers" (esp if you drop something), "forgive me", "pardon me", "I didn't mean to", "it was an accident", "my fault". But you're probably best sticking to "I'm sorry". It's fine.