Hubble's Law Recession Velocity Calculator
Calculate the recession velocity of a distant galaxy based on its distance from Earth using Hubble's Law.
Results will appear here.
Formula
v = H₀ × d
- v = Recession velocity of the galaxy (km/s)
- H₀ = Hubble Constant (km/s/Mpc) — the rate of expansion of the universe
- d = Proper distance to the galaxy (Megaparsecs, Mpc)
1 Megaparsec (Mpc) = 3.085678 × 10²² m ≈ 3,261,563.78 light-years
Speed of light c = 299,792.458 km/s
Assumptions & References
- The default Hubble Constant of 70 km/s/Mpc is a commonly used approximation. Current measurements range from ~67 km/s/Mpc (Planck CMB data) to ~73 km/s/Mpc (distance ladder measurements), reflecting the ongoing "Hubble tension."
- Reference: Hubble, E. (1929). "A relation between distance and radial velocity among extra-galactic nebulae." PNAS, 15(3), 168–173.
- Reference: Planck Collaboration (2020). Astronomy & Astrophysics, 641, A6. H₀ = 67.4 ± 0.5 km/s/Mpc.