What's the chance of getting pregnant 2-3 days after your supposed ovulation day?

10-15%: For a normal couple, the chances of achieving pregnancy each month spontaneously is around 10-15%.

2-3 days: After a sure ovulation is late for conception and chances would be slim to none. Don't be discouraged though, most home methods of monitoring for ovulation look at lh surge (not ovulation itself, ) and 2 days following a surge is likely still ok.