Product dimensions measured on a flatly laid out product.
Tip: measure an item of clothing at hand to compare.
While a bag of holding appears to be a common cloth sack of about 2 by 4 feet (0.6 by 1.2 m) in size, it opens into a nondimensional space (similar to magic satchel), making its inside larger than its outside dimensions. Each bag always weighs the same amount, between 15 and 60 pounds (7 and 27 kg), regardless of what is put into it. It can store a combined weight of up to forty times its own weight, and a combined volume of 30 to 250 cubic feet (0.8 to 7 m³). A living creature put in a bag of holding will suffocate after about 10 minutes. If a bag of holding is overloaded, or if sharp objects pierce it (from outside or inside), the bag will rupture and be ruined, the contents lost forever in non-space. (description from Wikipedia)