Equal to or Less than, but Greater than question

[JCrain]

I have a quite complex list of variables to put into a formula to come up with the correct number and I need some help to figure this one out. I don't know if it would be easier to set up a chart and then index the chart to do a lookup or how I need to go about doing this to achieve the most efficent solution.

I need the following to go into one formula:

1. =< 24 needs to show the number 24
2. =< 30 but > 24 needs to show 30
3. =< 32 but > 30 needs to show 32
4. =< 36 but > 32 needs to show 36
5. =< 40 but > 36 needs to show 40
6. =< 48 but > 40 needs to show 48
7. =< 50 but > 48 needs to show 50
8. =< 60 but > 50 needs to show 60
9. => 60 needs to show 60

I am trying to set up a spread sheet to figure square footage of plastic laminate countertops, but the plastic laminate only comes in several stock sizes : 3x8, 4x8, 5x8
3x10, 4x10, 5x10
3x12, 4x12, 5x12

So if I have a countertop that is 25 sq ft., I cant use a 3x8 (24 sq. ft), so I need to go up to the next size which would be a 4 x 8.

I might need to use a ROUNDUP function with this formula too? I already have cells set up to figure the depth, backsplash height, and front edge height and then give me the squage footage of that.

I am attaching a copy of what I have created so far if someone needs to see an example of what I am trying to do.

Thank you for the help.