Todd, it was pretty accurate. MY BEST time slip: 1/8th mile= 6.55 1/4 mile = 10.45 calculator says 10.37 based on 1/8x1.5832 calculator says 6.60 based on 1/4 (divided) 1.5832 Not a science and I wouldn't want to dial-in using it .....but pretty decent guesstamation.