Business Card Size

The standard dimensions for a printed business card are 3.5 x 2 inches. That's the finished card size.
If a business card is larger than 3.5 x 2 inches then it probably won't fit into a wallet and people don't want to carry an over sized business card around.

Many printed designs include bleed. The "bleed area" is an extra 1/8 inch of space for design elements or backgrounds that extend beyond the finished size of your piece. A business card design with bleed is printed slightly oversized and then cut down to size, giving the appearance that the printing "bleeds" off the edge of the card, rather than having white borders.




http://www.printingforless.com/2/Business-Card-Specifications.html