What is the formula used?

The calculator uses the magnitude of the Lorentz magnetic force: |F| = |q|vB sin(θ), where q is the charge in coulombs, v is speed in m/s, B is magnetic field strength in tesla, and θ is the angle between the velocity and field vectors. The sign of q changes the force direction, not its magnitude.

Why is the force zero at 0° and 180°?

Because sin(0°) = 0 and sin(180°) = 0. The magnetic force is a cross-product: when velocity is parallel or anti-parallel to the field, there is no perpendicular component and the force vanishes.

What is the maximum force?

The force is maximum when θ = 90°, because sin(90°) = 1. This occurs when the particle moves perpendicular to the magnetic field.

What units does this calculator use?

Charge in coulombs (C), velocity in meters per second (m/s), magnetic field in tesla (T), and the result in newtons (N). These are standard SI units.

Can I use negative charge values?

Yes. Enter a negative value for q to represent negative charges such as electrons. The magnitude of the force will be the same, but the direction of deflection is reversed in practice.

What is the charge of common particles?

An electron has a charge of -1.602 × 10⁻¹⁹ C, a proton has +1.602 × 10⁻¹⁹ C, and an alpha particle has +3.204 × 10⁻¹⁹ C. Use the preset buttons to fill these in automatically.

Magnetic Force Calculator

Calculate the magnetic force on a charged particle (F = qvB sin θ) by entering charge, velocity, field strength, and angle.

Input Parameters

Charge, q (coulombs)

Velocity, v (m/s)

Magnetic Field, B (tesla)

Angle, θ between v and B: 90°

0°45°90°135°180°

Or type an angle:

Result

Fill in the parameters and press Calculate Force.

Summary

The Magnetic Force Calculator computes the magnitude of the force exerted on a charged particle moving through a magnetic field using |F| = |q|vB sin(θ). Simply enter the particle's charge, speed, the magnetic field strength, and the angle between the velocity vector and the field direction. Results are displayed in Newtons with a clear step-by-step breakdown.

How it works

Enter the particle charge (q) in coulombs or use preset values for common particles.
Enter the particle velocity (v) in meters per second.
Enter the magnetic field strength (B) in tesla.
Set the angle (θ) between the velocity vector and the magnetic field using the slider.
The calculator applies |F| = |q|vB sin(θ) and displays the force magnitude in Newtons instantly.
Use the breakdown panel to see each factor and the intermediate sin(θ) value.

Use cases

Physics homework and exam preparation involving magnetic force problems.
Lab exercises exploring the Lorentz force on electrons or protons.
Engineering calculations for particle beam deflection systems.
Verifying hand-calculated results for charged particle motion in magnetic fields.
Visualizing how angle affects magnetic force (zero at 0° and 180°, maximum at 90°).
Teaching aid for demonstrating the cross-product nature of the magnetic force.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu