This briefcase has three compartment but the main one is 15" width x 11.5" tall x 4" deep, too much space for what you need big Laptop or Mac big books or document .
Second department is with along zipper 13" with x 10" Tall mostly used for Mac pro or Mini laptop as Mini 9.
Third compartment: 15"width x 11" tall deep to hold clothes books and your day meal ...
beside a massive external pocket which is measured 11" width x 5.6" tall x 1.9 deep including 5 external pens pockets ...
The shoulder strap length is 48" from the right metal ring which attaching strap to the left ring ...