Xtykutl

In column D (Result), I would like to have the following formula.

For each Cell in column C, find in column B the first value higher than the value of the cell of column C (starting from the same row) and gives as output the difference between the values found in column A (Count).

Example:
the value in C2 is 40. the first cell of B that has a value higher than 40 is B6. So D2 takes A6.value - A2.value = 5 - 1 = 4.

Can it be done without the use of VBA?

It can easily be accomplished with an array formula (so you have to enter the formula with Ctrl+Shift+Enter ) :
{=MATCH(TRUE;IF(B2:$B$7>C2;TRUE;FALSE);0)-1}

Put this formula in cell D2, and just drag down. You only have to change the end of your data set (change $B$7 into the real last cell of the column with data)

The formula works as follows :

• The IF statement results in an array with TRUE/FALSE values that meet your criteria : {FALSE;FALSE;FALSE;FALSE;TRUE;FALSE}
  


• The MATCH (with the 0 switch) searches the array for the index of the first match, which is 5 in our case


• And you have to subtract 1 to get the offset to the cell where the function is placed, so this gives you 4
  

So although you have to enter it as an array formula (you will get an N/A error without the ctrl+shift+enter), the result is just a single number.

Also, depending on your data set, you might want to add some ERROR handling in case no match has been found, e.g. just using the example data set in your question, the result in cell D5 will be N/A so you have to decide what value you want the result to be in such case.

And finally, I did not use the values in column A, as I assumed this is just a sequential ascending counter. If this is not the case, and you specifically want to find the difference between the corresponding values in that column, you can use the variant mentioned by Foxfire... in one of the other answers: =MIN(IF(B2:$B$6>C2;A2:$A$6))-A2

A slightly adjusted and shortened answer on Peter K.'s suggestion:
In D2:

=MATCH(TRUE,$B3:B$7>C2,0)

enter the formula with ctrl+shift+enter

Something like this should work for you. First transform your range to a table.

=IFERROR(AGGREGATE(15,6,--([@Second]<[First])*(ROW([@Second])<=ROW([First]))/--([@Second]<[First]*(ROW([@Second])<=ROW([First])))*[Count],1) - [@Count],"")

In this formula the comparison between [second] and [First] starts at the same row. That means that the value in D5 is 0 and not 1. (Like @Foxfire And Burns And Burnslike stated in the comments).

Ok, I did not post the answer waiting until OP answered why D5 is 1 instead of 0, but my formula is also an array formula. It would be:

=MIN(IF(B2:$B$6>C2;A2:$A$6))-A2

To type this formula in array mode, you need to type it as usual, but instead of pressing ENTER, you need to press CTRL+SHIFT+ENTER