We compute the critical behaviour of three-dimensional scalar theories
using a new exact non-perturbative evolution equation. Our values for
the critical exponents and other universal constants agree well with
previous precision estimates. The evolution equation describes the sca
le dependence of the effective average action (coarse-grained effectiv
e action). It is not restricted to critical phenomena and can be used
in the presence of massless (Goldstone) modes dealing successfully wit
h the infrared problems. Our results establish the viability of our me
thod for precise computations in a non-perturbative context.