This transition to BEC occurs below a critical temperature, which for a uniform three-dimensional gas consisting of non-interacting particles with no apparent internal degrees of freedom is given by
where:
:  is the critical temperature,
:  is the particle density,
:  is the mass per boson,
:  is the reduced Planck constant,
:  is the Boltzmann constant,
:  is the Riemann zeta function ().
Interactions shift the value, and the corrections can be calculated by mean-field theory.
This formula is derived from finding the gas degeneracy in the Bose gas using Bose–Einstein statistics.