Try the below and once you get it how to work combine it to a single formula
Col A Col B Col C
Feet Inches In inches
2 3 =A2*12+B2
4 3 =A3*12+B3
=C2+C3
In cell C4 =c2+c3
=INT(C4/144) & " sq feet " & MOD(C4,144) & " inches"
PS: Also take a look at CONVERT() Converts a number from one measurement
system to another.. part of Analysis ToolPak add-in.
If this post helps click Yes