Hubble Time

Order-of-magnitude Hubble time 1/H0 from H₀ in km/s/Mpc.

Inputs

H₀ (km/s/Mpc)

Tab to move between fields

Results

~Hubble time (Gyr)

14.51

1/H₀ (s)457,815,664,836,795,200

How to Use This Calculator

Enter the Hubble constant H0 (km/s/Mpc) -- current best estimate is ~67-73 km/s/Mpc.
Review the Hubble time in billions of years (Gyr) and in seconds.
Note that Hubble time (1/H0) is an upper bound -- the actual universe age (~13.8 Gyr) is slightly less.
Explore how uncertainty in H0 (the Hubble tension) affects the estimated age of the universe.

How the result changes with H₀ (km/s/Mpc)

H₀ (km/s/Mpc)	~Hubble time (Gyr)
21	46.57
71	13.77
130	7.52
180	5.43

What each input means

H₀ (km/s/Mpc): Planck ~67.4.

How this is calculated

Worked example, using the default values

Identify Input Parameters
H₀ (km/s/Mpc) = 67.4 = 1 input(s) provided
Calculate ~Hubble time
~Hubble time = 978 / h0
14.51 = 14.51
Calculate 1/H₀
1/H₀ = 1 / mpcPerS
457815664836795200 = 457815664836795200

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