The inch is a short unit of length used in imperial and United States customary systems. One inch is exactly 2.54 centimeters.
The inch developed from older local measures tied to the body. The modern international inch has been fixed at exactly 25.4 millimeters since 1959.
Measurement system: Imperial and US customary systems. SI equivalent: 1 in = 25.4 mm = 2.54 cm.
Inch facts
- Unit name
- Inch
- Symbol
- in
- Category
- Length
- Measurement system
- Imperial and US customary systems
- SI equivalent
- 1 in = 25.4 mm = 2.54 cm
- Common uses
- Displays, piping, fasteners and technical catalogs
Definition of the inch
The inch is a short unit of length used in imperial and United States customary systems. One inch is exactly 2.54 centimeters.
Measurement system and SI relationship
Imperial and US customary systems
SI equivalent: 1 in = 25.4 mm = 2.54 cm
History of the inch
The inch developed from older local measures tied to the body. The modern international inch has been fixed at exactly 25.4 millimeters since 1959.
Where is the inch used?
Displays, piping, fasteners and technical catalogs