I'm having difficulty figuring out how to create an equation and would appreciate help creating the equation or direction to reference material. I'm using Excel 2010 and Windows 7. I'd like to sum the monthly "Forecast" values, but only if "Actual" values for the month are entered. I would like to create a formula to do this so I don't have to continually change the =C3+E3+G3+I3 formula each time an actual data point is entered into the spreadsheet as shown below. I've trying things with SUMIFS, SUMPRODUCT, HLOOKUP, but can't seem to put the right combination together or locate a similar issue in a previous thread. Any suggestions would be great! Thanks.