Punched card

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A punched card (also punch card^[1] or punched-card^[2]) is a stiff paper-based medium used to store digital information via the presence or absence of holes in predefined positions. Developed over the 18th to 20th centuries, punched cards were widely used for data processing, automation, and computing. Early applications included controlling weaving looms and recording census data. In the 20th century, they became central to business operations and early computers for input, output, and storage. IBM's 80-column format became a dominant standard, and punched cards were used for decades before being replaced by magnetic storage and terminals. Their influence persists in cultural references, standardized data layouts, and computing conventions such as 80-character line widths.

Punched cards were once common in data processing and the control of automated machines.

Punched cards were widely used in the 20th century, where unit record machines, organized into data processing systems, used punched cards for data input, output, and storage.^[3][4] The IBM 12-row/80-column punched card format came to dominate the industry. Many early digital computers used punched cards as the primary medium for input of both computer programs and data.

Data can be entered onto a punched card using a keypunch.

While punched cards are now obsolete as a storage medium, as of 2012, some voting machines still used punched cards to record votes.^[5] Punched cards also had a significant cultural impact in the 20th century.