McCarthy's side notched a late 2-1 home win over Doncaster on Saturday to sit outside the play-offs on goal difference with four games to go.
The Ipswich boss admits there are a few sides still in with a chance of making the play-offs, but once there it will be a lottery and momentum will be key.
He told the Green'Un24:"We have got a chance of being promoted to the Premier League. That is effectively what it is. We keep talking about finishing in the play-offs, but if you do get in there then who knows what will happen.
"Somebody who perhaps wasn't fancied to get in there will sneak in there. It could be us, it could be Bournemouth, it could be Brighton. Whoever it is will be going into it with momentum. Any one of us will prove difficult opposition for anybody.
"Those play-offs are such a lottery. Who knows what will happen? It is exciting that we're still involved."
He added: "We've got four games left. I suppose if we win all four... is that likely? We've got Watford up next (away on Saturday), they're a very good side, then it's Bournemouth (home on Easter Monday) who have got eight wins and two draws out of their 11 games.
"There are some big games coming up. It's exciting."