First things first - no - that's not my firewood chainsaw - just one I have here in town.
Having not cut firewood regularly in the better part of 30 years, apparently I'm not very good at it, or I've developed the stereotypical male trait of not being able to tell length because I always think 14" is 16".
There's something called a Firewood Buddy you can stick to the saw and go down and mark your whole log and come back and cut it. Only $16, shipped, but that's about $14 too much for a stick on a magnet
https://www.amazon.com/Firewood-Buddy-detachable-firewood-measuring-chainsaw/dp/B00IJJT9LAAnd $16 more than what I paid for mine, which is a magnet hook with the hook lug drilled out, a 15 3/4" piece of tomato stake, and a drywall screw.