Physics

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Lorentz Force Calculator.

Calculate magnetic force magnitude on a moving charge.

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01

Set your values

Results update as you type.

Force: 0 N

Force

0.000000N

Results update automatically as you type.

Use Cases

Physics homework and exam prep

Quickly verify Lorentz force calculations for textbook problems or practice exercises involving charged particles in magnetic fields.

Example: Calculate the force on a proton (q=1.6e-19 C) moving at 5e6 m/s in a 0.5 T field at 30°.

Engineering design of particle systems

Estimate magnetic forces in devices like mass spectrometers, particle accelerators, or magnetic deflection systems.

Example: Determine the force on an electron beam in a CRT at a given field and angle.

Frequently Asked Questions

What is the Lorentz force?
The Lorentz force is the force experienced by a charged particle moving through a magnetic field. Its magnitude is given by F = qvB sin(θ), where q is charge, v is speed, B is magnetic field strength, and θ is the angle between velocity and field.
How do I use this calculator?
Enter the charge in coulombs (C), speed in meters per second (m/s), magnetic field strength in teslas (T), and the angle between velocity and magnetic field in degrees. The calculator will compute the force magnitude in newtons (N).
What if the angle is 0 or 90 degrees?
If the angle is 0°, the force is zero because sin(0)=0. If the angle is 90°, the force is maximum because sin(90°)=1. The calculator handles any angle between 0 and 180 degrees.

Tips & Common Mistakes

Tips

  • Ensure the charge is in coulombs (C). For elementary charges, use 1.6e-19 C for a proton or -1.6e-19 C for an electron.
  • Speed must be in meters per second (m/s). Convert from km/h by dividing by 3.6.
  • The angle is between the velocity vector and the magnetic field vector. Use degrees as provided.
  • The result is the magnitude of the force in newtons (N). The direction is perpendicular to both v and B, but this calculator only gives magnitude.

Common Mistakes to Avoid

  • Forgetting to convert angle to radians if using a manual formula; this calculator uses degrees, so no conversion needed.
  • Using the wrong sign for charge: the magnitude is always positive, but the direction depends on sign. This calculator gives magnitude only.
  • Entering speed in km/h or miles per hour instead of m/s, leading to incorrect force values.

Last updated: August 13, 2026