Square inch (in²)
Definition
Exactly 6.4516 cm² (2.54 cm squared).
History
The square inch is a square one inch on each side, derived from the inch fixed at 2.54 centimeters in 1959. It equals exactly 6.4516 square centimeters.
Where it is used
Square inches measure small parts, print areas and screens.
Typical uses include small parts, print and screens.
Conversion pages
These pages convert square inch to or from another unit in area.
No conversion pages use this unit yet.
Other Area units
Sources
- NIST HB 44 NIST Handbook 44, Appendix C (area); 1959 yard-and-pound agreement · Dataset reviewed Nov 11, 2026