Then right click the cells used the formula, and select Format Cells from the context menu, then in the popping Format Cells dialog, under Number tab, click Date in the Category list, then select the date type in the right section. Click OK, now you can see the Unix timestamps have been converted to dates. In the formula, A1 is the date and time cell, C1 is the coordinate universal time you typed. This formula also can use to convert timestamp series to date and time, just format the result to the date and time format. A1 indicates the timestamp cell you need.