A calling card or business card is a small rectangle of cardboard with the name and contact details of an individual or company printed on it. The card will usually have a telephone number, email address, business address and full name. It may have a logo, a small picture that is officially representative of the company or the individual, and maybe a motto or mission statement, which the company puts on it's advertising. All of these are meant to advertise and to inform the recipient of the card. They are considered effective as they are cheap to produce and will often be tucked into a pocket or put on a shelf instead of discarded.

Calling cards started in antiquity and would be used by aristocracy. They were originally visiting cards, simply used to state a person's name and introduce them rather than advertise business. The servants of a card owner would give the card to the household staff of the recipient. They had a status as a tool of etiquette and proudly displayed coats of arms and used fine printing techniques and elegant script. They serve a second purpose of providing a list of those who had visited a person or as a contacts directory. Later on they increasingly became the tool of merchants who to this day give out the cards as cheap advertising. The cards may have a map to the shop and may, particularly with nightclubs, be redeemable for a service such as cheaper entry or a free drink. The distinction between a business card and a visiting card is largely ignored except in a few social circles. To some, leaving a business card instead of a visiting card or vice versa is a breach of etiquette.

Calling cards are often of high quality and may have a colour photograph of the individual. They are usually the size of a credit card but variations occur. There are even CD-ROM business cards, essentially a small CD in the shape of a normal business card. Apart from the normal details on the front they can be accessed by a computer's CD drive, allowing the individual or company to put a variety of information on it. They can display video, images and have links to websites and other online documents. These cards are still in low circulation.