No clue on the exact length, but mine reached from a floor spot near the door to the outlet without an extension cord. That was with the heater maybe four or five feet out, so I’d guess it’s a fairly standard cord. Floor spot out of the walking path makes sense to me.
I still like having the phone up where I can glance at it even if the dot stops moving, mostly so I know roughly how far I’ve gone in. Mine usually catches up once there’s sky again.
I tried the whole solo blind thing once and it lasted about two days before I peeked. Now I just pick a mode and stick with it for a week, then switch, and accept that it’s more of a vibe check than real science.