When is your period actually over?!

Ashley • Wife. Mommy. TTC baby #2
This sounds like the dumbest question... But I'm 26 and newly TTC and accurately trying to map out my cycle.  Unlike a lot of women, I have never been on birth control. So my cycle can fluctuate but is almost always regular. My question is... what is the actual last day of a period? Is it When you have light brown spotting? Or when the spotting stops all together ? My glow chart says this is my peak day of ovulation and I'm so excited but what if I have my cycle chart messed up by inaccurately logging?! Feeling stressed... Would love your opinions