The Distance to the Galactic Center of the Milky Way is 27,000 light years. The value above is in light-years (ly). However, this can be automatically converted to other distance units including parsecs, megaparsecs and kilolight-years.
Astronomy Calculator contains basic formulas for a college level Introduction to Astronomy
Exoplanet Calculator contains formulas for studying planets outside of our Solar System.
Astronomical Distance Calculator provides the distance from the Earth to numerous astronomical bodies (e.g. Sun, Moon, planets, stars, Milky Way's Center and Edge, Andromeda Galaxy)