How do you count days of fast duration?

This might be a silly question, but how do you count the days when talking about the duration of a fast? Like let’s say I fast from 8pm on a Monday night to 8pm the following Friday. Would you call that a four-day fast, because Friday is four days after Monday? Or would it be a three-day fast, because there were only three days where I didn’t eat anything (Tuesday, Wednesday, and Thursday)? I know I could just say it’s a 96-hour fast, but I personally prefer thinking of fasts in terms of days rather than hours. Edit: I’m not having trouble keeping track or anything (I already use an app), I’m more just wondering how you all personally consider it. Like when someone says they did a 3-day fast, do they mean 72 hours (2 full days without eating)? Or do they mean 3 full days without eating (so more than 72 hours)?