The SI unit of force is the Newton .
1 Newton is the force that accelerates 1 kilogram of mass at the rate of 1 meter per second-squared.
1 pound of force is roughly 4.45 Newtons of force.
So 1 Newton of force is roughly 3.6 ounces of force.
1 kilogram of mass weighs about 9.81 Newtons on Earth. That's the same as 2.205 pounds.