How this calculator works
A current circulating around a loop produces a magnetic dipole moment normal to the loop. Identical turns add their moments, giving N times current times area. A solenoid uses its cross-sectional area, rather than its lateral surface area or length. The signed result follows a chosen area normal and the right-hand rule. A magnetic core contribution is not included in this free-current moment.
Formula
m = N I A. For circular turns, A = pi r² = circumference²/(4 pi). I = m/(NA), A = m/(NI) and N = m/(IA).
Worked example
A single loop of area 3 m² carrying 2 A has moment 6 A m². A ten-turn circular coil of radius 1 m carrying 2 A has moment 20 pi = 62.83185 A m².
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Frequently asked questions
Does coil length enter this formula?
No. The dipole moment depends on enclosed area, current and turns. Length affects the field distribution of a solenoid.
What does a negative moment mean?
It points opposite to the selected area normal because the current direction is reversed.
Does an iron core multiply this result?
The winding free-current moment stays NIA. Total moment including material magnetization needs a separate material model.