What does "my bad" mean?

"My fault" or "I made a mistake." It's a casual, low-key admission of error without a full apology. When you knock into someone lightly, forget a small detail, or say something slightly wrong, "my bad" is the quick way to own it. Think of it as shorthand for "yes, that was on me, no big deal." It doesn't carry the weight of a heartfelt sorry, and it isn't meant to. It's the verbal equivalent of a small shrug and a nod.

"My bad" emerged from American basketball slang in the 1970s-80s and went mainstream in the 1990s. It's shorter and less formal than "I apologise" or "that was my fault." The tone is light, it acknowledges the mistake without making a big deal of it. On the court, a player who threw a bad pass would say "my bad" to signal the error and keep the game moving, and that same quick, no-drama spirit carried into everyday speech. Natives reach for it because it clears the air instantly without stopping the conversation.

With friends, colleagues you know well, or in casual situations. Not appropriate in a formal apology or professional email, use "I apologise" or "that was my mistake" instead.

Here are some natural examples:
"Oh, I grabbed your coffee by accident. My bad!"
"My bad, I sent you the wrong file. Here's the right one."
"You wanted the meeting at three, not four? My bad, I'll fix the invite."
"Sorry I'm late, totally my bad, I lost track of time."

Notice how "my bad" fits small, everyday slip-ups. For anything serious, such as missing an important deadline or upsetting someone, it can sound too flippant.

Informal. Universally understood in American English; well-known in British English though less commonly said. In the workplace, a quick "my bad" is fine among a friendly team over chat or in person, but in a written email to a client or your boss you should switch to "apologies" or "my mistake." In casual settings, "my bad" is completely at home. British speakers understand it perfectly thanks to American film and television, though many Brits still lean towards "sorry" or "my fault" in the same moment.

Learners sometimes try to expand it into "my bad thing" or "it is my bad," which sound wrong to native ears. The phrase is frozen and complete on its own, so keep it as just "my bad." You can add a short apology or explanation after it, as in "My bad, I'll do it again," but do not try to stretch the two words into a longer grammatical sentence. Another slip is using it in a formal apology where it undercuts your sincerity, so save it for light moments.

Picture a basketball player raising one hand after a fumble and calling out "my bad" while jogging back into position. The image ties the phrase to its origin and reminds you of the tone: quick, casual, and already moving on. Two words, one hand up, no drama.

A few phrases live in the same casual space. "My mistake" is slightly more neutral and works in a wider range of settings, including semi-formal ones. "That's on me" is another American favourite that means the same as "my bad" but sounds a touch more grown-up and responsible, good for the workplace. "Oops, sorry" is even lighter and often used for tiny physical bumps. Knowing all of these gives you options depending on how formal the moment feels, so you can match your words to the situation with confidence.