ToolHub

Cosmology Calculator

Estimate recessional velocity from Hubble law, evaluate Friedmann expansion behavior, and compute the Universe critical density with SI or astronomical units.

Use Cases

  • - Intro cosmology homework and exam practice
  • - Quick checks for expansion and redshift intuition
  • - Comparing cosmological parameter assumptions
  • - Building intuition before simulation workflows

Formulas Used

  • Hubble law: v = H0 d
  • Low-z redshift: z ~= v / c
  • Friedmann: H(a)^2 = H0^2 [Omega_r a^-4 + Omega_m a^-3 + Omega_Lambda + Omega_k a^-2]
  • Critical density: rho_c = 3H0^2 / (8*pi*G)

Calculation History