There is an IF nesting  limit that is something like seven for excel  up to
2003. I believe 2007 has relaxed that significantly.

I am having severe problems with your description:

- "Chart" is a graphic item in Excel, can I assume you mean "column" on a
worksheet?

- "Variable" is a programming term - do you mean "value"?

- There are not 49 values in your message - there are only 44.

- You say you want to find  the number  that is the next larger, but your IF
statement will return a value that is the same as C5. Which is correct?

- Your first IF clause is IF(C5<=1,0) which is not consistent with your
stated requirement or with the rest of your IF statement. Should it be
IF(C5<=1,1)?

You say you've tried VLookUp but have had no luck. What VLookUp formulae
have you tried? What did they do wrong?

A solution  to your stated requirement "I need to have excel find the number
on a chart  that is the next number larger than C5" is

=INDEX($A$1:$A$44,IF(C5<$A$1,0,MATCH(C5,$A$1:$A$44,TRUE))+1,1)

This will grab the first number from the range A1:A44 that is greater than
the number in C5.

So C5 with 1-5.9999 will get the first one (6); C5 with 6-11.749999 will get
the second one (11.75), etc.