How the force calculator works
This tool applies Newton second law of motion, force equals mass times acceleration. Choose which quantity to solve for, force, mass, or acceleration, enter the other two, and it returns the answer. It also converts the force to pounds force and expresses acceleration as a multiple of gravity.
Newton second law
Force equals mass times acceleration, written F equals m times a, with force in newtons, mass in kilograms, and acceleration in meters per second squared. Rearranged, mass is force divided by acceleration, and acceleration is force divided by mass. One newton is the force that accelerates one kilogram at one meter per second squared.
Weight versus mass
Weight is the force of gravity on a mass, found by multiplying mass by gravitational acceleration, about 9.8 meters per second squared on Earth. So a 10 kilogram object has a weight of about 98 newtons. Mass stays the same everywhere, but weight changes with gravity, which is why you would weigh less on the Moon.
Everyday uses
Use it for physics homework, estimating the thrust or braking force needed for a given acceleration, or understanding g forces. Expressing acceleration in g, multiples of Earth gravity, gives an intuitive feel: a few g is a hard launch or hard braking, while sustained high g is dangerous to the human body.
Frequently asked questions
What is Newton second law? Force equals mass times acceleration; rearrange to solve for any of the three.
How do I find weight from mass? Multiply mass by gravity, about 9.8 meters per second squared on Earth.
What is one newton? The force that accelerates one kilogram at one meter per second squared.
Related calculators: Kinetic Energy, Ohm Law, Density.