Length Converter for Metric, Imperial & Scientific Units
This length converter turns any measurement from one unit into another the moment you type it. Enter a value, pick a source unit, and every other unit updates instantly — no Convert button, no page reload.
It covers 14 length units across three systems: metric (kilometer down to ångström), imperial (mile, yard, foot, inch), and other (nautical mile, light year). That makes it useful for students mixing metric and imperial in homework, engineers and architects reading international specs, travelers gauging distances abroad, online shoppers checking product dimensions, and scientists working at microscopic or astronomical scales.
How to Use the Length Converter
Enter your value
Type a number into the input field, for example 100. You can use either a comma or a period for decimals, and large numbers may be written with spaces — both are accepted.
Pick the source unit
Open the unit dropdown and choose what your value is measured in, such as Meter or Inch. Start typing in the search box to filter the list when you have many units to scan.
Read every conversion
The results list below shows your value converted into all enabled units at once, grouped by Metric, Imperial, and Other. Everything updates in real time as you type.
Copy what you need
Click the copy icon on any row to copy that single value, or use Copy All Results to grab every conversion at once. A confirmation appears when the copy succeeds.
Want fewer units in the list? Click Customize Units to toggle any unit on or off, and use the Decimals dropdown to set precision. Your choices are saved automatically for next time.
Features
Real-Time Conversion
Results appear instantly as you type. No Convert button and no page reload — the converter recalculates every enabled unit on each keystroke.
14 Length Units
Metric (km, m, dm, cm, mm, μm, nm, Å), imperial (mi, yd, ft, in), plus nautical miles for navigation and light years for astronomy.
Swap & Search Units
Switch the from and to units with one tap, and filter the dropdown with a search box so the unit you need is always a few keystrokes away.
Customizable Display
Toggle individual units on or off so the results list shows only the ones you care about. Your selection is remembered for future visits.
Adjustable Precision
Choose 2, 4, 6, or 8 decimal places, or pick Auto to show full precision while trimming unneeded trailing zeros.
One-Click Copy
Copy any single result with its row button, or use Copy All Results to put every converted value on your clipboard at once.
Unit Reference Guide
Expand the Unit Reference panel for a quick guide to each unit — its symbol, value in meters, and what it is typically used for.
Mobile Friendly
The layout adapts to your screen, with touch-friendly controls on phones and tablets and a numeric keypad for entering values.
Dark Mode Support
A built-in dark theme follows your system preference or the site theme so the converter is comfortable in any lighting.
Private & Offline
All math happens locally in your browser. No values are sent to a server, and the converter keeps working without an internet connection.
Frequently Asked Questions
How many centimeters are in a meter?
One meter equals 100 centimeters. Enter 1, choose Meter as the source unit, and the centimeter row shows 100. The same step works for millimeters (1 m = 1,000 mm) and kilometers (1 km = 1,000 m).
How do I convert centimeters to inches?
Pick Centimeter as the source unit and type your value — the inch row updates instantly. Because 1 inch is exactly 2.54 cm, 2.54 cm shows as 1 inch. To go the other way, just choose Inch as the source instead.
How do I convert feet to meters?
Select Foot as the source unit and read the meter row. One foot equals exactly 0.3048 meters, so the converter handles the factor for you whether you are working with a single value or a whole list of measurements.
Which length units does it support?
Fourteen in total. Metric: kilometer, meter, decimeter, centimeter, millimeter, micrometer, nanometer, and ångström. Imperial: mile, yard, foot, and inch. Other: nautical mile and light year. Use Customize Units to hide any you do not need.
Are the conversions exact?
Yes. The converter uses standard scientific factors — for example, 1 inch = exactly 2.54 cm and 1 mile = exactly 1,609.344 m — and you can show up to 8 decimal places. Each unit is converted through meters as the common base for consistent results.
Why are some numbers shown in scientific notation?
Very large or very small numbers switch to scientific notation so they stay readable. For instance, "1.5e+9" means 1.5 × 10⁹, or 1,500,000,000. This keeps results clear when you convert between everyday units and extreme scales like nanometers or light years.
What is an ångström, and what is a light year?
An ångström (Å) is 10⁻¹⁰ meters, or 0.1 nanometers — used in physics and chemistry for atoms and wavelengths of light. A light year is the distance light travels in one year, about 9.46 × 10¹⁵ meters, used in astronomy to measure distances between stars and galaxies.
Can I use the length converter offline?
Yes. Once the page has loaded, every calculation runs locally in your browser, so you can keep converting without an internet connection. Your values and saved preferences stay on your own device and are never sent to a server.
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