I don't really know how to answer because I don't have a good understanding of where you're headed with this. Date fields ALWAYS contain a time of day component in addition to the date. When you enter a date with no associated time, the time is assumed to be midnight. So, relating to your previous post, adding some number of minutes to that is probably not going to work for you. If 8.5 hours is equal to a day, you should probably divide the estimated number of minutes by 510 and add full days to the start date. Then store the remaining minutes in a separate field.