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Inch (in)

Exactly 25.4 millimeters; the base small unit of US customary and Imperial length.

Result25.4

1 inch = 25.4 millimeters

Inch at a glance

Unit nameInch (plural: inches)
Symbolin
Quantity measuredLength
Measurement systemUS customary
Also known asin, ", inch, inches
Definition exact?Yes — exact by definition

1 inch in other length units

Unit1 in equals
Nanometer25,400,000 nm
Micrometer25,400 µm
Millimeter25.4 mm
Centimeter2.54 cm
Decimeter0.254 dm
Meter0.0254 m
Kilometer0.0000254 km
Foot0.083333333 ft
Yard0.027777778 yd
Mile0.000015783 mi
Nautical mile0.000013715 nmi
Angstrom254,000,000 Å
Mil1,000 mil
Fathom0.013888889 ftm
Rod0.005050505 rd
Chain0.001262626 ch
Furlong0.000126263 fur
League0.000005261 lea
Astronomical unit1.69788513 × 10⁻¹³ au
Light-year2.68478212 × 10⁻¹⁸ ly
Parsec8.2315794 × 10⁻¹⁹ pc

Popular inch conversions

Frequently asked questions

What is a inch?
Exactly 25.4 millimeters; the base small unit of US customary and Imperial length.
What is the symbol for the inch?
The symbol for the inch is in. It measures length.
How many millimeters are in a inch?
1 inch = 25.4 millimeters.
How many centimeters are in a inch?
1 inch = 2.54 centimeters.
How many meters are in a inch?
1 inch = 0.0254 meters.