The length of the parsec used in IAU 2015 Resolution B2 (exactly ⁠ 648 000 / π ⁠ astronomical units) corresponds exactly to that derived using the small-angle calculation. This differs from the classic inverse- tangent definition by about 200 km, i.e.: only after the 11th significant figure. As the astronomical unit was defined by the IAU (2012) as an exact length in metres, so now the parsec corresponds to an exact length in metres. To the nearest meter, the small-angle parsec corresponds to 30 856 775 814 913 673 m.