Many star catalogs give the distance to a star (if known) as parallax, usually in milli-arcseconds. To convert this value to something more useful, like Astronomical Units, we can use the conversions below.
The parsec is dependent on the measurement for 1 AU, so you may see different conversion factors depending on the definition of an AU. The IAU has adopted the conversion factor of \( 1\ parsec = \frac{648,000}{\pi}AU \). So simply multiply parsecs by this constant to yield AU.