Understanding The MICR Line

On any modern check, a merchant may notice a line of information positioned along the bottom. This line is the key to standardized check reading – by standardizing the information contained, check can be routed faster and less prone to human error.

MICR is an acronym for Magnetic Ink Character Recognition. The “MICR Line” contains standardized characters, in a specific font, that are printed using magnetic ink. The ink (or toner) contains iron oxide which is magnetized, which allows reading in a manner not unlike a tape recorder, and can provide more accurate reads than standard OCR techniques.

The MICR line identifies numerous facts about the check that it is printed on – The account holder’s bank, the account number, the check number and possibly other optional fields. The information is always printed in a standardized location on a check in a described font. The MICR line font used in the United States is known as E-13B and was designed to be human readable and clear to a machine simultaneously. Additionally, only three types of characters are acceptable in the MICR line- numbers, spaces and symbols.

In the MICR line itself, information is printed into predefined fields. These field locations encompass standardized character space ranges. For example, locations 33 through 43 contain the routing number of the bank that holds the account the check is drawn on.

Standards for the MICR line are defined by the Accredited Standards Committee X9 Inc. The standards document is available here .