What determines how much gravity a star will have?

Question

What determines how much gravity a star will have?

Answer 1

as with any other thing the gravity is determined by the mass of the object, be it star. planet, asteroid or what have you.

Answer 2

The force that a body exerts due to gravity on another object is proportional to the product of both their masses.

F = G*M*m/r^2

Where G is the gravitational constant, M is the mass of one of the objects, m is the mass of the other object, and r is the distance between them.

Answer 3

Primarily the mass, but also the density. Very high densities, such as are found in neutron stars and black holes, lead to very strong tidal forces.

Edit: Newton's Law of Gravitation (given in MooseBoy's answer) is a good approximation when gravity is weak, but if fails for strong gravitational forces. Then it needs to be replaced by Einstein's General Theory of Relativity.