Magnetic Dipole Moment Calculator
Calculate a current loop's magnetic moment, torque, and potential energy in a magnetic field.
About magnetic dipole moment
Magnetic dipole examples
These ideal current-loop examples use SI units.
| Inputs | Results | Interpretation |
|---|---|---|
| I = 2 A, A = 0.5 m², N = 1, B = 0.2 T, θ = 90° | μ = 1 A·m², τ = 0.2 N·m, U = 0 J | A perpendicular loop experiences maximum torque. |
| I = 3 A, A = 0.02 m², N = 50, B = 0.4 T, θ = 0° | μ = 3 A·m², τ = 0 N·m, U = -1.2 J | An aligned coil is at minimum potential energy. |
| I = 0.5 A, A = 0.01 m², N = 100, B = 0.1 T, θ = 180° | μ = 0.5 A·m², τ = 0 N·m, U = 0.05 J | An antiparallel coil is an unstable equilibrium. |
How to use the calculator
- Enter the current through the loop in amperes.
- Enter the area of one turn in square metres and the number of turns.
- Provide the external magnetic field in teslas and the angle to the moment vector.
- Select Calculate dipole moment to obtain moment, torque, and potential energy.
Frequently asked questions
What is magnetic dipole moment?
Magnetic dipole moment is a vector measure of a magnetic source's strength and orientation. For an ideal coil, its magnitude is the number of turns times current times loop area.
Why does the number of turns multiply the moment?
Each identical turn creates a moment in the same direction. Their contributions add, so a tightly wound N-turn coil has N times the moment of one turn under the ideal model.
Which angle should I enter?
Enter the angle between the magnetic moment vector and the external magnetic field. It is not generally the angle between the plane of the loop and the field, because the moment is normal to that plane.
When is magnetic torque greatest?
The torque reaches its greatest magnitude when the moment and field are perpendicular at 90 degrees. It becomes zero at 0 or 180 degrees, although the antiparallel state is unstable.
Can I use centimetres and milliteslas?
Convert them before entering values because this calculator expects SI units. Divide square centimetres by 10,000 for square metres and divide milliteslas by 1,000 for teslas.