Decimal fraction

how about this... =LEFT(A2,SEARCH(".",A2)-1)+(RIGHT(A2,1)/12)
this is provided each are in their own cells, if they are all in one cell that will require a different approach because then excel will be treating them as text.

With slight modification, the DOLLARDE() function is built for just this scenario: https://support.office.com/en-us/art...d-a38476693427 You would need to input two decimal places instead of 1; instead of 10.1, you would need to enter as 10.01 (10.1 would correspond to 10' 10"). Then =DOLLARDE(10.01,12) would return 10 1/12 or 10.08333....

If you plan to enter that exact text string in a single cell, instead of each dimension in its own cell, you will need text function (LEFT(), MID(), RIGHT()) to extract the numeric portions of the text string. My inclination has always been to input each dimension in its own cell, though, avoiding this step.

Each dimension has its own cell. So I have a column for each length, width, and height and a column that multiplies them all to give me cubic feet.

then my formula should work for you assuming your entries are 10.1 and not 10-1.

but you have no data in the sheet so I can tell where you need the formula or formulas. Whatever cell has the value, 10.1 for example, if it is in A2 then you'd need another cell to put the formula in so each location where you have a value you'll need another cell to convert it. To do it differently you likely will need a VBA solution (which is a skill set I don't have).

Either formula should work for you, a lot depends on exactly how you prefer to implement it.

My formula will treat 10.1 and 10.10 as the same thing (10 feet 10 inches). It looks to me like Sambo Kid's formula may not capture the 10 or 11 inch numbers, since it is only extracting the rightmost character. None of your examples show numbers with 10 or 11 inch parts, so maybe this is not necessary. However, a robust feet.inch converter needs to be able to handle x.10 and x.11 values as well. For either formula, I would always use 2 digits in the decimal/inch portion (x.01, x.02, x.03,...,x.11). Sambo Kid's text based formula would simply need to edit the RIGHT() part of the function to take the 2 rightmost characters. Mine would not need any change to the formula.

It is up to you how you want to proceed.

Mr Shorty, 10.1 is (original post) 10 feet 1 inch.

@Sambo kid: that is correct as the OP described, but is 10.1 going to always mean 10 feet 1 inch? When you input 10.1 into Excel, Excel will automatically interpret that as a number (unless you force it to receive text input). If the OP enters 10.10 (10 feet 10 inches), this will look exactly the same to Excel as 10.1 (10 feet 1 inch), which can make it difficult to distinguish between 10 feet 1 inch (10.1) and 10 feet 10 inch (10.10) entries. Always entering 2 digits past the decimal eliminates this ambiguity and simplifies the processing. As I noted, this would be unnecessary if the OP will never (and I do mean never) need x.10 or x.11 values, but only the OP knows if that is a possibility. I am suggesting to the OP that she/he change that input so that 10 feet 1 inch is input as 10.01.

@MrShroty, I see your point. Mine works perfectly for the examples given but falls apart for 10 and 11 inch measurements. I could adjust it with a LEN statement or another search on the Right part to account for 11 but since excel drops trailing zeros unless it is text a .10 would screw it up. hmmm

So based on MrShorty's observations, this would work for all values from .1 to .11 inches. Including .10 (10 inches) IF you change the cell to text...
=LEFT(A2,SEARCH(".",A2)-1)+((MID(A2,SEARCH(".",A2)+1,3)/12))
but if you use dashes instead of decimals so that instead of 10.10 it would show as 10-10 and 3-6 then this would work for all instances too...
=LEFT(A2,SEARCH("-",A2)-1)+((MID(A2,SEARCH("-",A2)+1,3)/12))