Light Year Calculator

Your details

Choose which unit you are starting from. The calculator converts it to all other units automatically.
Enter the distance in the unit selected above. The default is the distance to Proxima Centauri, the nearest star outside our solar system (4.244 light years).
Choose the unit you want highlighted in the main result card. All other units appear in the secondary outputs below.
Switch to "travel time" mode to ask how many years, days or seconds it takes light to travel a given distance.
Result
40.1513 trillion km
Kilometres40.1513 trillion km
Miles24.9489 trillion mi
Astronomical Units (AU)268395.13 AU
Parsecs1.301216 pc
Light years4.244000 ly
Metres (scientific notation)4.0151e+16 m

4.244 ly = 40.1513 trillion km

  • This is less than the distance to Proxima Centauri (4.244 ly), the nearest star to our Sun.
  • Light leaving a source this far away has been travelling for 4.2440 years before reaching you - you are seeing that source as it was 4 years ago.
  • In kilometres, this is roughly 40.15 trillion km.

Next stepUse the reference table below to compare this distance with well-known stars, galaxies and cosmic structures.

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