Clock minutes are sixtieths of an hour. Treating 30 minutes as .30 hours is the common mistake; the correct value is .50.
Use total minutes divided by 60
Eight hours and 15 minutes is 495 minutes. Dividing 495 by 60 gives 8.25 decimal hours. Converting the complete total is simpler and safer than converting every shift separately.
Remember the useful fractions
Fifteen minutes is .25 hour, 30 minutes is .50, and 45 minutes is .75. Six minutes is .10 hour. These checkpoints quickly expose a minutes-as-hundredths mistake.
Round once, at the end
WorkHours retains integer minutes and presents the decimal total to two places. Use H:MM when exact minutes matter. A payroll or billing system may impose a different rounding policy, which this calculator does not choose for you.