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Inch(in)

The inch is a unit of length in the imperial and US customary systems, defined as exactly 25.4 millimeters.

Reviewed

Symbol
in
Quantity
Length
Measurement system
Imperial and US customary
SI classification
Non-SI unit
Reference unit
Meter
Exact relationship
1 in = 0.0254 m exactly

Visualizing inch

The marked distance represents a length of 1 in. The illustration is conceptual and not drawn to physical scale.

What the inch is

The inch is a common small-unit measurement in everyday US and UK contexts, especially for screens, hardware, and construction.

Convert Inch