The word “even” has many meanings, it often serves as an adverb to emphasize something unexpected (She doesn’t even know her teacher’s name.). When it is an adjective, it can be used to describe something being smooth, in numbers (even numbers – odd numbers) or the equality of 2 things – this is its meaning in the phrase “call it even”.
“Call it even” is used in situations involved 2 or more people that owe each other money or favor, or when we compare this person with another person. It means that both are equal or no longer owe each other anything.
+ “She broke my heart and I wanted to do the same to call it even but I found out she doesn’t have one.” – Ansel Guarneros
(Meaning: I wanted to break her heart in order to make it equal, because she broke mine.)
+ I’m responsible for cooking and my brother does the cleaning. We call it even.
(Meaning: I do this, my brother do that, and it’s fair, it’s equal.)
+ You were being annoying and I was a pain too, so maybe we can call it even?
(Meaning: You were bad to me but I was bad to you, so we are equal.)