This can be accomplished with VBA only. There is no native formula within Excel to support this. This is a fairly small piece of code..
1. Make a backup of your workbook.
2. Open your workbook and ALT+F11
3. Locate your Workbook name in Project Explorer Window
4. Right click on your workbook name > Insert > Module
5. Copy and Paste the below code in the module
6. Save your file as .xlsm
7. Call your macro as
In place of A1:C6, your can put your range.
Next 3 digits are RGB codes. For Yellow, they are 255, 255 and 0...To know the RGB code of any colour, select your cell and click on down pointing arrow on Fill Colour symbol and go to custom to pick up RGB code.
---- Macro by E for Excel ----
Function SumColorCells(Rng As Range, R, G, B)
Dim Cell As Range
For Each Cell In Rng
If IsNumeric(Cell) And Cell.Interior.Color = RGB(R, G, B) Then
SumColorCells = SumColorCells + Cell