I have researched and found that the dimensions from the outside edges of the storage bins would be close to 12". For more information you may contact the manufacturer directly at 800-221-0400. For pricing and availability please contact Customer Service. They will be glad to help with your question. You may contact them at http://www.staples.com/sbd/content/help/contact/index.html
or by phone at 800-333-3330. Thank you for your inquiry.
Answered on 1/9/2012 by Christina.M from Staples