» Adding Time Values
When using a standard SUM formula to add the time values in column B (=SUM(B2:B5)), a false result of 4:23 is returned, rather than the actual sum of 28:23.
Excel's default time format does not allow a time value to exceed 24 hours. This is the cause of the above error.
To properly display a sum exceeding 24 hours, change the format of the cell from "h:mm" to "[hh]:mm".