I tried to calculate a formula once, to convert increment of Earth's mass to increment of Earth's gravity for a planet of the same density, so not the same as escape velocity but sort of related. I'm not sure if it's actually correct but it was: x/x^(2/3) So i.e. for 5 Earth masses and the same density, it would be 1.71 of Earth's gravity on the surface, 10 masses -> 2.15 Earth's gravity.

Reasoning: Acceleration is GM/R^2 and planets R is like (x * Me / 4Pi / density)^1/3 . Directly proportional to M and inverse square root of radius, while the radius is directly proportional to (x)^(1/3)

Though the density for 2 planets made of the same stuff and different masses would probably be different due to differences in pressure in its internals? Just a guess.