Lorentz Force Calculator
Enter a charge, a velocity, and a magnetic field strength to get the magnetic force in newtons — the push a field gives a charge moving across it.
Magnetic force in one step
Enter the charge, velocity, and field strength and the calculator returns the magnetic force F = q × v × B in newtons.
Use SI units
Charge in coulombs, velocity in metres per second, and field in teslas give the force in newtons — and the motion is assumed perpendicular to the field.
What is the Lorentz force?
The magnetic push on a moving charge
This Lorentz force calculator finds the magnetic force a field exerts on a moving electric charge. A charge sitting still in a magnetic field feels nothing, but the moment it moves across the field lines the field pushes on it sideways. That push is the Lorentz force, and it is what bends electron beams, spins the rotor of an electric motor, and steers particles around an accelerator ring. The size of the force depends on three things: how much charge is moving, how fast it travels, and how strong the field is. Enter those three values — charge in coulombs, velocity in metres per second, and field strength in teslas — and you get the force in newtons.
Enter a charge, a velocity, and a field strength to get the magnetic force in newtons instantly.
When a charge moves perpendicular to a magnetic field, the magnetic force is simply the charge multiplied by the velocity multiplied by the field strength.
F = q × v × BTake an electron, which carries a charge of about 1.6e-19 C, moving at 1,000,000 m/s through a magnetic field of 0.5 T. Multiply the three values together: 1.6e-19 × 1,000,000 × 0.5 = 8e-14 N. The force is tiny because the charge of a single particle is tiny, yet it is more than enough to curve the electron into a tight circle. Each input scales the force directly: double the velocity and the force doubles; double the field and it doubles again.
The formula is exact for perpendicular motion, but a few points are worth keeping in mind.
Perpendicular motion and the electric term
This calculator gives the magnetic force for a charge moving perpendicular to the field. The general case depends on the angle θ between the velocity and the field: F = q × v × B × sin θ, so the force shrinks to zero when the charge moves along the field lines. The complete Lorentz force also adds an electric term, F = q(E + v × B); if an electric field is present, add the electric force qE separately. Keep your units in coulombs, metres per second, and teslas so the result comes out in newtons.