Right, can answer that after todays experience. Petrol station coming out of Telford was shut, with petrol light on I drove roughly 25 miles not knowing where the next nearest station was (this is in my cup by the way). Drove very conservatively, and managed to find one, so after it goes blank youve got at least another 10 maybe 15 miles left. Basically, it seems very accurate, and when it says youve got 60 left, you probably have, if it hasnt been re-set in a while anyway.