Primary formula
F = qvB sin(theta); F = ILB sin(theta).
Physics calculator
Magnetic Force Calculator
Calculate magnetic-force magnitude for a moving charge or a straight current-carrying wire in a magnetic field.
Last reviewed: July 21, 2026Physics formula engine v3.0.0
Physics calculator
Magnetic Force Calculator
Enter values, select units and calculate locally. Results use SI internally and show rounded display values.
Decimal.js physics math
Mode
Find force on a moving charge in a magnetic field.
Result and visual stay hidden until you choose Calculate.
Formula and assumptions
Input assumptions
Magnetic field magnitude is nonnegative. Speed or wire length is nonnegative. The entered angle is between the direction of motion/current and the magnetic field.
Precision note
Physics calculators convert compatible inputs into SI units before calculating. Decimal.js is used for arithmetic where practical; trigonometric angle factors are rounded for display.
Physics calculation flow
Parse
Read labelled inputs, selected units and calculation mode from the calculator card.
Convert
Convert compatible values to SI base or derived units without calling external services.
Calculate
Apply the selected deterministic mechanics formula and validate against NaN, Infinity and invalid divisors.
Label
Display the result, supporting unit rows, formula steps, warnings and dynamic visual below the input card.
What Magnetic Force Calculator does
Use this calculator for ideal Lorentz-force and wire-force examples where the angle to the field is known.
The calculator is deterministic and runs from manual inputs only. It is a physics formula tool, so it should not be confused with a unit converter that only changes labels after a value is already known.
Formula and variables
F = qvB sin(theta); F = ILB sin(theta).
The calculator converts supported units into SI base or derived units for the actual calculation, then formats the result in the selected display unit.
- q is charge
- v is speed
- B is magnetic flux density
- I is current
- L is wire length
- theta is angle to field
Worked examples
Use the examples below to check expected order of operations and unit handling before applying the tool to your own values.
- 1 C x 2 m/s x 3 T x sin(90 deg) = 6 N
- 5 A x 2 m x 0.4 T x sin(30 deg) = 2 N
- Parallel motion gives zero magnetic force.
Unit conversions
Length, time, mass, area, volume, speed, force, pressure, density, frequency, energy and power units reuse the central NexaCalc conversion registry. Acceleration, angle and spring-constant units use the same SI-first convention where applicable.
The displayed conversion rows are supporting context. They do not change the physical assumptions of the selected formula.
Common mistakes
Most errors come from mixing physical quantities that sound similar in everyday language or choosing a unit that belongs to a different dimension.
- Using cosine instead of sine.
- Forgetting gauss to tesla conversion.
- Ignoring that magnetic force direction is vector-based.
Assumptions and limitations
This page is intended for educational and planning calculations, not professional engineering certification.
This calculator uses idealized physics formulas and the input values you provide. Real systems may require additional effects such as friction, drag, rotation, deformation, losses or measurement uncertainty.
- Magnetic field magnitude is nonnegative.
- Speed or wire length is nonnegative.
- The entered angle is between the direction of motion/current and the magnetic field.
- The calculator reports magnitude and does not draw full right-hand-rule vector orientation.
- Nonuniform fields and curved paths require more detailed modeling.
Frequently asked questions
How is magnetic force calculated?
Magnetic Force Calculator uses F = qvB sin(theta); F = ILB sin(theta). The result is calculated from the values and units entered in the form.
What angle is used in magnetic force?
Use this calculator for ideal Lorentz-force and wire-force examples where the angle to the field is known. Magnetic field magnitude is nonnegative.
Why does the formula use sine?
Magnetic Force Calculator uses F = qvB sin(theta); F = ILB sin(theta). The result is calculated from the values and units entered in the form.
How do I calculate force on a current-carrying wire?
Magnetic Force Calculator uses F = qvB sin(theta); F = ILB sin(theta). The result is calculated from the values and units entered in the form.
What is a tesla?
Use this calculator for ideal Lorentz-force and wire-force examples where the angle to the field is known. Magnetic field magnitude is nonnegative.
Can gauss be used in this calculator?
Use this calculator for ideal Lorentz-force and wire-force examples where the angle to the field is known. Magnetic field magnitude is nonnegative.
Does charge sign affect direction?
Use this calculator for ideal Lorentz-force and wire-force examples where the angle to the field is known. Magnetic field magnitude is nonnegative.
How is magnetic force different from Coulomb's Law?
Use this calculator for ideal Lorentz-force and wire-force examples where the angle to the field is known. Magnetic field magnitude is nonnegative.
Does this calculator include nonuniform fields?
Magnetic Force Calculator uses an idealized classroom physics model. The calculator reports magnitude and does not draw full right-hand-rule vector orientation.
When should I use a vector diagram?
Use this calculator for ideal Lorentz-force and wire-force examples where the angle to the field is known. Magnetic field magnitude is nonnegative.
References
- NIST Special Publication 811, Guide for the Use of the International System of Units. Relevance: SI unit symbols and derived-unit naming. Last verified: July 21, 2026. Source.
- BIPM, The International System of Units SI Brochure. Relevance: SI base and derived units used in mechanics, fluids, waves and optics. Last verified: July 21, 2026. Source.
- OpenStax University Physics Volume 1. Relevance: introductory formulas for motion, force, work, energy, momentum, fluids, waves and optics. Last verified: July 21, 2026. Source.
- NIST CODATA internationally recommended values. Relevance: physical constants for electricity, modern physics, gravitation and radiation formulas. Last verified: July 21, 2026. Source.
- OpenStax University Physics Volume 2. Relevance: electric circuits, capacitance, magnetic force and electromagnetic waves. Last verified: July 21, 2026. Source.
- OpenStax University Physics Volume 3. Relevance: photons, nuclear decay and blackbody radiation concepts. Last verified: July 21, 2026. Source.
Physics references verified for SI units, mechanics, fluids, waves, sound and optics formulas on July 21, 2026.
Educational disclaimer
This calculator provides mathematical results from the values, conventions and methods you enter. Verify important academic, engineering or professional work independently.