When do you ovulate?

Hey ladies, me and my husband have been TTC for about 6 months now, This month I started doing ovulation test to help the process. I have several apps to help narrow down my fertility window and 1 or 2 of them say I should have ovulated by now but all my tests have been negative. I'm on day 16 of my cycle. just curious when other ladies ovulate, let me know! :)