SOLVED: Significant figures in seconds to hours calculation 1. The problem statement, all variables and given/known data Not exactly a problem, but if I have minutes/seconds and am changing to hours, how many significant figures are there? For example: 29 minutes 57 seconds =0.499166667 hours needs ? significant figures. 3. The attempt at a solution Well, a second to 1/3600 hours. Therefore, I think I might want to measure to a precision of one ten-thousandth of an hour, or possibly 1/1000 hours. I'm not sure which. I know that the minutes doesn't affect the calculation, and I know that the unit conversion is considered to have infinite sig figs.