Length Converter

The length converter is a fully bidirectional, multi-unit tool. Enter a value in any length unit and every other field updates automatically. It covers three categories: metric units, imperial/US units, and other units including nautical miles, Sun radii, and light years — making it one of the most complete convert of length tools available.

Common Length Unit Conversions

The calculator covers two main unit systems:

Metric units: Kilometer (km), Meter (m), Decimeter (dm), Centimeter (cm), Millimeter (mm), and other metric units via expandable dropdown.

Imperial/US units: Inch, Foot, Yard, Mile, and other imperial units via expandable dropdown.

Other units: Nautical miles (nmi), Sun radii (Ro), Light years (ly), and additional units via expandable dropdown.

The Length Conversion Formula

All length conversions follow the same principle: multiply or divide by the conversion factor between the two units.

The general formula:

Target Value = Source Value × Conversion Factor

For example, to convert centimeters to inches, multiply by 0.394. To go the other direction — inches to centimeters — multiply by 2.54. Every unit pair has its own conversion factor, and the calculator applies them all automatically.

How the Length Converter Works

Inputs and Outputs

Metric section:

• Length in millimeters (mm)

• Length in centimeters (cm)

• Length in meters (m)

• Length in kilometers (km)

• Length in other metric units — expandable dropdown (default: μ)

Imperial/US section:

• Length in inches (in)

• Length in feet (ft)

• Length in yards (yd)

• Length in miles (mi)

• Length in other imperial units — expandable dropdown (default: ft)

Others section:

• Length in nautical miles (nmi)

• Length in Sun radii (Ro)

• Length in light years (ly)

• Length in other units — expandable dropdown (default: nmi)

Buttons: Share result, Reload calculator, Clear all changes.

Enter any single value and all other fields populate instantly. The tool converts in every direction simultaneously.

How to Use the Length Converter — Step by Step

Example 1: Centimeters to Inches

Convert 10 centimeters to inches.

10 cm × 0.394 = 3.94 inches

Enter 10 in the centimeters field and the inches field shows 3.94 instantly.

Example 2: Kilometers to Miles

Convert 1 kilometer to miles.

1 km × 0.621 = 0.621 miles

Example 3: Feet to Meters

Convert 1 foot to meters.

1 ft = 0.305 meters

Enter 1 in the feet field and the meters field updates to 0.305 automatically on CalcyMate's convert to length tool.

Length Conversion Reference Chart

Metric Conversions

Standard to Metric Conversions

Note: All values sourced from the Metric to Standard Conversion Chart — Length provided with this calculator.

Frequently Asked Questions

How do you convert centimeters to inches?

Multiply the number of centimeters by 0.394. For example, 10 cm × 0.394 = 3.94 inches. You can also divide by 2.54 to get the same result. Enter the cm value in the length converter and the inches field updates automatically.

How many centimeters are in an inch?

One inch equals exactly 2.54 centimeters. This is a fixed, defined conversion — not an approximation. So 1 in = 2.54 cm, and to convert inches to centimeters, multiply by 2.54.

How many meters are in a kilometer?

There are exactly 1,000 meters in one kilometer. The prefix "kilo" always means one thousand in the metric system. So 1 km = 1,000 m, and to convert kilometers to meters, multiply by 1,000.

How many feet are in a meter?

One meter equals approximately 3.281 feet. To convert meters to feet, multiply by 3.281. To go the other way — feet to meters — multiply by 0.305. Enter either value in the length conversion formula tool and the result appears instantly.