 <p>Assuming the strings are all in column A:</p> <p>As you will only want to split where there are 2 or more characters, just to start you off. In <strong>Column C</strong> is the formula (this is only in column C):</p> <pre><code>=IF(LEN(A1)&gt;1,CONCATENATE(LEFT($A1,1),"_",MID($A1,2,1),"_"),"") </code></pre> <p>In <strong>Column D</strong> and dragged across is the formula:</p> <pre><code>=IF(LEN($A1)&gt;COLUMN(C:C),CONCATENATE(C1,MID($A1,COLUMN(C:C),1),"_"),IF(LEN($A1)=COLUMN(C:C),CONCATENATE(C1,RIGHT($A1,1)),"")) </code></pre> <p>That will build the string for you but the results will be all over the place so in <strong>Column B</strong> I have the formula:</p> <pre><code>=INDEX(1:1,1,LEN(A1)+1) </code></pre> <p>To gather all the results in to one column for you. Feel free to ask how any of this works, I hope this helps.</p> <p><a href="https://i.stack.imgur.com/HEMFS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HEMFS.png" alt="Example"></a></p>