Convert astronomical unit to chain (US survey) Online | Free Length Converter

Astronomical Unit

An astronomical unit (AU) is a unit of distance used in astronomy to describe the average distance between the Earth and the Sun. It equals about 149.6 million kilometers (or about 93 million miles). The AU is useful for measuring distances within our solar system, such as the distance from Earth to other planets. For example, Mars is about 1.5 AU from the Sun. Using the AU makes it easier to understand and compare distances between planets without dealing with very large numbers. The symbol for astronomical unit is "AU".

Chain (US Survey)

The US survey chain is a unit of length used historically in land surveying in the United States. It is defined as exactly 66 US survey feet, which is slightly longer than the international foot. Since one US survey foot equals about 0.3048006096 meters, the US survey chain is approximately 20.11684 meters long.

Like the standard chain, it is divided into 100 links, each measuring 0.66 US survey feet. The US survey chain was widely used in the Public Land Survey System to measure land parcels and boundaries.

Key facts:

• 
  

  1 US survey chain = 66 US survey feet

  
  
• 
  

  1 US survey chain ≈ 20.11684 meters

  
  
• 
  

  10 US survey chains = 1 furlong

  
  
• 
  

  80 US survey chains = 1 US survey mile

  
  

Though the US survey foot and chain are being phased out in favor of international units, the US survey chain still appears in historical land records and some legal contexts.