Punched card

A 12-row/80-column IBM punched card from the mid-twentieth century

A punched card (also punch card^[1] or punched-card^[2]) is a piece of card stock that stores digital data using punched holes. 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.

Close-up of a Jacquard loom's chain, constructed using 8 × 26 hole punched cards

Punched Card Media

Carpet loom with Jacquard apparatus by Carl Engel, around 1860. Chain feed is on the left.
Woman operating the card puncher, c.1940
Clerk creating punch cards containing data from the 1950 United States census.
A deck of punched cards comprising a computer program. The red diagonal line is a visual aid to keep the deck sorted.
Hollerith card as shown in the Railroad Gazette in 1895, with 12 rows and 24 columns.
Punched card from a Fortran program: Z(1) = Y + W(1), plus sorting information in the last 8 columns.
An 80-column punched card with the extended character set introduced with EBCDIC in 1964.
Binary punched card.