I copied this off of Whittlesfabrics website on what their shipping charges are. Tells you roughly how many yards per...
SHIPPING CHARGES
Orders are shipped by U.S Priority Mail or U.S. Priority Flat Rate, whichever is less expensive. We are not responsible for damaged, lost or stolen items. Insurance can be purchased if requested. Please allow 5-7 business days for delivery. You will receive confirmation email when your packaged has been shipped. We make every effort to save you money on the shipping. If you have any special shipping requests, please notify us.
Domestic Shipping Rates
$4.95 Flat Rate envelope-approx. 8-9 yards of fabric (45" cotton - non-flannel)
$10.70 Flat Rate Box-ups to 25 yards of fabric (45" fabric - non-flannel)
$14.50 Large Flat rate box 45 yards of fabric - (45" fabric - non-flannel)
Hope this helps some.