Help with a calculation - Weight greater/less

[Trent_Hatred]

Hi folks,

I'm hoping someone out there might be able to help me with a calculation I'm trying to do.

I have a weight field in a MySQL database field. I need to calculate shipping costs based on that weight.

So, anything under 20lbs = no shipping
If the weight is 20lbs = shipping is $10.00
For every additional 10lbs, shipping is another $10.00.

Thanks much,
B

[paulnaj]

$shipping = $weight < 20? 0: 10*ceil(($weight - 20)/10);

Note:
19lbs -> $0

20lbs -> $10
21lbs -> $10
...
29lbs -> $10

30lbs -> $20

etc