working in inches appears to create problems

[Anonymous]

It has been days trying to figure this what I thought was a simple formula.

All I am trying to do is calculate board foot (bf) from these outputs
w = 1 1/2"
h = 5 1/2"
L = 12'

I have found that when doing the board foot formula is is in metric so I had to multiply it by 424. Is this the best way to do this?

Formula: parameters bf = (w*h*l)*424

That formula does work, not sure if I can do something different so I do not have to multiply it by 424, any suggestions?

My issue with this is the w and h needs to be rounded to the nearest inch before being added to the formula so w needs to be rounded to 2" and h needs to be rounded to 6". I tried to use ceil() but again it converts to metric or something???

Any suggestions on what I am doing wrong?

Thanks for any and all help

John

[Erika Epstein]

you need to add in a factor that makes all the measures the same. Your current formula has two in inches and the other in feet. Your goal is a volume. A correct version of the
board footage calculation is

(thickness " x width" x length")/144 sq. in.

in your example: (2" x 6" x (12x12))/144 sq.in.

[Anonymous]

Any ideas on a formula to round a length of 1 1 /2" to 2"?
Thanks

[Anonymous]

Erika wrote:
(thickness " x width" x length")/144 sq. in.

Minor quibble, one board foot = 144 cu in.

Also important to remember is that board feet are typically calculated for nominal rough dimensions. So a surfaced 1 1/2" for framing lumber or 7/4" for hardwoods is calculated as 2" thick. Widths are similarly handled for dimension lumber but different for sawn one edge, random lengths and widths and rough both edges (these are basically up to the tallyman).

One other thing. For the lengths you have to calculate the waste factor. This can vary considerably depending on how close the cut lengths are to the standard ones.

[Anonymous]

camp20 wrote:
Any ideas on a formula to round a length of 1 1 /2" to 2"?
Thanks

IF length >= 1 1/2" AND length < 2" THEN length = 2"

Of course I haven't seen a lot of inch and a half long boards