no big deal

no big deal

1. Not inconvenient or difficult at all; not at all troublesome. A: "Thanks so much for watching the kids for me last night, there was an emergency at work." B: "No big deal, man. I'm happy to help out." It's no big deal if you want me to drive you to the airport tomorrow.
2. Of no great or particular importance or consequence. A: "I heard your team won last night—congrats!" B: "It's no big deal, we were against a pretty weak team. But thank you all the same!" A: "It was just a little pot—it's no big deal!" B: "No big deal? Tom, you could get kicked out of school for this!"
See also: big, deal, no
Farlex Dictionary of Idioms.

no big deal

 and no biggie
Inf. [of something] not difficult or troublesome. Don't worry. It's no big deal to wash the car. No problem. It's no biggie.
See also: big, deal, no
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

no big ˈdeal

(spoken) used to say that something is not important or not a problem: If I don’t win it’s no big deal.
See also: big, deal, no
Farlex Partner Idioms Dictionary

no big deal

and no biggie and no big whoop
n. (something) not difficult or troublesome. (see also NBT.) Don’t worry. It’s no big deal. No biggie; no prob.
See also: big, deal, no
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • not exactly
  • not for a second
  • not for a minute
  • not for a moment
  • aint
  • ain't
  • not for a instant
  • not for a/one minute/moment/second/instant
  • by no means
  • not by any means