Newbie Formula Question - how to get formula to repeat in each subsequent row?

[admiral_victory]

I have an excel s/s which shows in one column a reading of a central
heating gas usage , In an adjacent column I want it to automatically
show the increment in this gas usage reading when I enter a subsequent
reading here.

I have inserted the formula :-

=IF(C16="","",C16-C15).

This calculates the difference between C16 & C15 entries but does not
do anything for an entry in C17 - the formula does not repeat as I
move down the C column.

I've forgoten how to do this - can someone remind me again , please ?

B.N.

 

[Dave Peterson]

Look at the formulas in those cells again. If the formulas adjusted, but the
value displayed in the cell hasn't changed, then there's a good chance you have
manual recalculation set.

In xl2003 menus:
tools|options|calculation tab
check automatic.

This setting is picked up from the first workbook you open in that session. You
may want to remember how to toggle it.

 

[admiral_victory]

Look at the formulas in those cells again. If the formulas adjusted, but the
value displayed in the cell hasn't changed, then there's a good chance you have
manual recalculation set.

In xl2003 menus:
tools|options|calculation tab
check automatic.

This setting is picked up from the first workbook you open in that session. You
may want to remember how to toggle it.

Thanks for the reply.

Recalculation was set to automatic.

I seem to have it sorted out now - after I enetered the formula in the
first cell I then changed the file to "hide formulae" and then just
pulled the cell downwards by holding down the little "handle" on the
botom rh side of the cell.

This got the fomulae to repeat and change as I scrolled down.

B.N.