Unit converter

Length converter

Convert metric, imperial, nautical, and astronomical length units.

Enter a value and choose units. Results update instantly.

1 in = 2.54 cm

All Length units

From 1 in
UnitValue
Meter m 0.0254
Kilometer km 0.0000254
Centimeter cm 2.54
Millimeter mm 25.4
Micrometer μm 25,400
Nanometer nm 25,399,999.9999999963
Inch in 1
Foot ft 0.0833333333
Yard yd 0.0277777778
Mile mi 0.0000157828
Nautical mile nmi 0.0000137149
Light-year ly 2.6847821184e-18
Recent conversions
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Common tasks

Inch to Centimeterin to cm Foot to Meterft to m Mile to Kilometermi to km Millimeter to Inchmm to in Meter to Footm to ft Kilometer to Milekm to mi

Reference

How length conversion works

Length measures the distance between two points. This converter uses the metre as its internal reference and preserves exact legal definitions for inch, foot, yard, mile, and nautical mile.

Values are converted to meter first, then from that reference into the requested unit. Keeping a single documented reference reduces inconsistent pair-by-pair constants.

Accuracy note: Metric factors and international inch, foot, yard, mile, and nautical mile definitions are exact.

Unit reference

UnitSymbol1 unit in m
Meterm1
Kilometerkm1,000
Centimetercm0.01
Millimetermm0.001
Micrometerμm0.000001
Nanometernm0.000000001
Inchin0.0254
Footft0.3048
Yardyd0.9144
Milemi1,609.344
Nautical milenmi1,852
Light-yearly9.460730472581e15

Long-tail directory

Every indexed conversion

Choose a source unit to see all available destinations.

From Meter (m)
Meter to KilometerMeter to CentimeterMeter to MillimeterMeter to InchMeter to FootMeter to YardMeter to MileMeter to Nautical mile
From Kilometer (km)
Kilometer to MeterKilometer to CentimeterKilometer to MillimeterKilometer to InchKilometer to FootKilometer to YardKilometer to MileKilometer to Nautical mile
From Centimeter (cm)
Centimeter to MeterCentimeter to KilometerCentimeter to MillimeterCentimeter to InchCentimeter to FootCentimeter to YardCentimeter to MileCentimeter to Nautical mile
From Millimeter (mm)
Millimeter to MeterMillimeter to KilometerMillimeter to CentimeterMillimeter to InchMillimeter to FootMillimeter to YardMillimeter to MileMillimeter to Nautical mile
From Inch (in)
Inch to MeterInch to KilometerInch to CentimeterInch to MillimeterInch to FootInch to YardInch to MileInch to Nautical mile
From Foot (ft)
Foot to MeterFoot to KilometerFoot to CentimeterFoot to MillimeterFoot to InchFoot to YardFoot to MileFoot to Nautical mile
From Yard (yd)
Yard to MeterYard to KilometerYard to CentimeterYard to MillimeterYard to InchYard to FootYard to MileYard to Nautical mile
From Mile (mi)
Mile to MeterMile to KilometerMile to CentimeterMile to MillimeterMile to InchMile to FootMile to YardMile to Nautical mile
From Nautical mile (nmi)
Nautical mile to MeterNautical mile to KilometerNautical mile to CentimeterNautical mile to MillimeterNautical mile to InchNautical mile to FootNautical mile to YardNautical mile to Mile

Primary source

Definitions and standards

Conversion constants and definitions for this category are checked against NIST SP 811: Guide for the Use of the SI.

See Methods & sources for rounding rules, exact-value handling, and review policy.

Questions

Length FAQ

What is the reference unit for length conversions?

ConvertWin uses meter (m) as the internal reference for this category, then converts to the selected output unit.

How accurate is this length converter?

Metric factors and international inch, foot, yard, mile, and nautical mile definitions are exact.