Barcode Scanners are hand-held or stationary devices used to read information contained in a barcode. These devices are connected to a computer through any type of port. Scanners cannot do calculations; they only capture the barcode into letters or numbers. Information, once fed into a computer is processed by the computer's software. A barcode scanner consists of a code reader and decoder. The reader throws light on a barcode and measures the amount of light that is reflected back by the barcode. This light energy is converted into electrical energy by a scanner. The electrical energy in turn is changed into data in the computer.

Barcode scanners are available in many different varieties. They can be hand held and hands free, wearable, rugged, scan engines, laser or digital. Pen-wand scanners are perhaps the simplest types of such devices. They have to be kept in direct contact with the barcode and held at a precise angle. A pen-wand scanner is moved over the bar to read it. General purpose scanners are generally used at checkout counters and hospitals and are also used to process identification documents. Certain other kinds of scanners, like rugged scanners, are generally used in harsh or extreme conditions.

Another major distinction of barcode scanners is that of an image scanner and a laser scanner. A camera reader is embedded in an image scanner. The camera captures the barcode images, which are then processed by sophisticated image techniques to decode the barcode. An image scanner can read a barcode from four to ten inches away. Laser scanners use lenses to read the codes. Laser scanners enjoy the advantage of reading the bar even from a distance of 24 inches. Moreover a laser scanner can be positioned at any angle to read a barcode. With the advancement of technology, modern laser scanners can read the barcodes with ease from a distance of 30 feet.