Lencon - Length Converter App
Lencon converts lengths between twelve units, from nanometres to light years. Type a value, choose the unit you have and the unit you want, tap Convert, and the answer appears with the full equation underneath, such as 6 m = 600 cm.
It is handy when metric and imperial units meet: a product listed in inches, a running route in miles, a room measured in feet, a sailing distance in nautical miles or a science homework problem in micrometres. The input box also accepts simple arithmetic, so you can type 2*3 or 10.5+4 and convert the total in one step.
Lencon runs in your browser with no account. Your recent conversions are listed in a history tab while the page is open.
The app runs entirely in your browser. What you enter is saved only on this device.
How to use Lencon
- Enter a value. Type a number into the input box. You can also type a short calculation using +, -, * and /, for example 5+2 or 12*3.
- Choose the units. Select the From and To units from the menus. The arrow button between them swaps the direction.
- Convert. Tap Convert. The result card shows the converted value and the full equation.
- Copy the result. Tap the copy icon on the result card to paste the value elsewhere.
- Look back. Open the History tab to see your recent conversions. Up to 20 are kept until you close or reload the page.
- Learn the units. Tap the info icon at the top for a short description of each unit and its size in metres.
Features
- 12 units: m, km, cm, mm, µm, nm, inch, foot, yard, mile, nautical mile and light year
- Simple arithmetic in the input (+, -, *, /)
- Swap button for the two units
- Result with the full conversion equation
- Copy to clipboard
- History of the last 20 conversions during your visit
- Unit reference with descriptions
- Interface in many languages
Metric and imperial lengths explained
The metric ladder
The metre is the SI base unit of length. Metric units step by powers of ten: a kilometre is 1,000 metres, a centimetre a hundredth of a metre and a millimetre a thousandth. Going smaller, a micrometre (µm) is a millionth of a metre, about the size of a bacterium, and a nanometre a billionth, the scale of molecules and the features on computer chips. Converting within the metric system is just a matter of moving the decimal point.
Imperial and US customary units
Since 1959 the inch has been defined as exactly 2.54 centimetres, which fixes the others: a foot is 12 inches (30.48 cm), a yard is 3 feet (0.9144 m) and a mile is 1,760 yards, or 1,609.344 metres. These units remain everyday measures in the United States and, for some purposes such as road distances and heights, in the United Kingdom.
Nautical miles and light years
A nautical mile is exactly 1,852 metres. It was originally linked to one minute of latitude, which makes it convenient for navigation at sea and in the air, and speed in knots means nautical miles per hour. At the other extreme, a light year is the distance light travels in a Julian year, about 9.46 trillion kilometres. Astronomers use it, along with parsecs, for distances between stars.
Avoiding conversion mistakes
Most real-world errors come from mixing units, not from arithmetic. Write the unit next to every number, round only at the end, and sanity-check results: a metre is a little more than a yard, a kilometre is about six-tenths of a mile, and 30 cm is about a foot. When accuracy matters, for example in construction or engineering drawings, check whether a value is nominal or measured before converting.
For quick estimates, remember that an inch is about 2.5 cm, a foot about 30 cm, a yard just under a metre and a mile about 1.6 km; a nautical mile is roughly 1.15 statute miles.
Frequently asked questions
Can I type a calculation?
Yes. Basic arithmetic with +, -, * and / is supported in the input box, and the result of the calculation is converted.
Is my history saved?
Only while the page is open. Reloading or closing the page clears it.
Which mile does Lencon use?
The international statute mile of 1,609.344 metres. Nautical miles are listed separately at 1,852 metres.
Why is a light year a length?
Despite the name, a light year measures distance, not time: it is how far light travels in one year. Lencon treats it as about 9.461 × 10^15 metres, so converting even a large number of kilometres gives a very small number of light years.
Does it need an internet connection?
Only to load the page. Conversions are calculated in your browser.
What is different from the phone app?
The converter is the same. The iPhone and Android apps show ads that a subscription removes; the web version has no ads or purchases.
Limitations of the web version
- History is cleared when the page is reloaded
- No custom units
- Results are shown for one target unit at a time
Phone app
Lencon is also available as an app for phones and tablets: