The inch equals 2.54 centimeters exactly since 1959. It is the global standard for screen diagonal sizes โ a "55-inch TV" has a 139.7 cm diagonal. Pipe diameters, US and UK shoe sizes, and hard-drive form factors are all specified in inches. 1 inch = 1/12 foot = 1/36 yard.
Real-world: A 65-inch TV has a 165 cm diagonal. A smartphone screen is typically 6โ7 inches. Standard copper plumbing in the UK is ยฝ inch or ยพ inch.
Read full inch reference โThe foot equals 30.48 centimeters exactly and is one of the oldest length units in human history. It is the international aviation standard for altitude โ commercial airliners cruise at 35,000 feet. In the US, building dimensions, human height and elevation are all expressed in feet. 1 foot = 12 inches.
Real-world: Airliners cruise at 35,000 ft (10.7 km). Mount Everest is 29,032 ft (8,849 m). A standard US ceiling is 8 ft (2.44 m).
Read full foot reference โ