Excel provides a pair of nifty shortcut keys that can be used to copy cells down and to the right. For instance, let’s say you want to copy the contents of cell C3 to the fifteen cells just below it. All you need to do is select the sixteen cells (making sure that cell C3 is the top cell in the selection) and then press Ctrl+D. Cell C3 is copied to all the other cells below it.
Likewise, if you want to copy cells to the right, you can simply make a selection and press Ctrl+R. The value of the left-most cell in the selection will be copied to its right, filling out the selected range.
You can combine these two shortcuts to fill an entire range of cells. Let’s say that you have a value in cell C3 and you want it copied to the range C3:M24. All you need to do is select that range and then press Ctrl+D and immediately press Ctrl+R. The first command copies the first row downward, which means that C3:C24 now contains the desired value. When you press Ctrl+R, everything in C3:C24 is copied to the right so that the entire range of C3:M24 is filled.