how close do you have to be for it to consider you on point to contest

[Jurro]

am i going crazy i see the square for the point so id imagine as long as your in that square you are on point but i feel like unless I'm touching it half the time it does not say I'm on the point which when trying to contest is really annoying i will be on the point defending/pushing and the game will end as if no one in on the point contesting it feels the range for it to count as on the point to contest is weird super weird if your a flying or slightly above the point

[Kyo Tanaka]

I don't know how high but the box is a clear indicator. Another factor you have to consider is the character's state: Are they completely invincible? IE, eaten by Jeff's ult, Psylocke's ultimate, vanishes in general (not stealth), achieving this sort of state on the point will make it so that you are not contesting the point while standing on it.

This doesn't apply if the character is just immune to damage, like when Hulk transforms.