Ok, so I have a simple =SUM formula =SUM(G2*H2) which works fine.

On another tab, I have a more confusing formula (SUMPRODUCT), which is looking in the same cell my =SUM formula is in which is causing the formula not to work and show #N/A.

If I take out the =SUM formula out and replace with just the value (130.58) it works fine.... but I'm creating this spread sheet for somebody else and I need to keep the =sum formula there and have the SUMPRODUCT formula work on the other tab at the same time?

Any ideas?

(sheet is attached. Please refer to 'Week 1' F6 and 'Data Input' column 'I'.Nordics - Weekly Costs.xlsx