It depends on the mass of the planet and the diameter. Since planets are usually sphere shaped, it effectively means that the gravity grows with diameter (for same density) and vice versa (for same diameter, grows if density grows). Moon is about 4 times smaller (for same density, gravity would be about 4 times smaller) but Moon has lower density as well (about 60% of Earth) so it comes down to those 16%.
Rough napkin formulas below. Apologies for formatting)
F=ma
F(g) = GMm/(r^2)
ma=GMm/(r^2)
a=GM/r^2
Volume of a sphere = (4/3)pir^3
mass of a planet = density volume
M=ro(4/3)pir^3
a=(Gro(4/3)pir^3)/r^2
a=Gro(4/3)pi*r
given that G, 4/3 and pi are constants, it comes just to density multiplied with diameter.
Rough napkin formulas below. Apologies for formatting)
F=ma F(g) = GMm/(r^2) ma=GMm/(r^2) a=GM/r^2
Volume of a sphere = (4/3)pir^3 mass of a planet = density volume M=ro(4/3)pir^3
a=(Gro(4/3)pir^3)/r^2 a=Gro(4/3)pi*r
given that G, 4/3 and pi are constants, it comes just to density multiplied with diameter.