Why This Magnetic Force Tool Helps
A bar magnet creates a curved field in nearby space. The field is strongest near the poles. It weakens quickly as distance grows. This calculator uses the magnetic dipole model. That model works best outside the magnet, and far enough from the pole faces. It gives useful estimates for classes, labs, and design checks.
Field Around a Bar Magnet
The magnetic moment describes the strength and direction of the magnet. Distance and angle set the observation point. At zero degrees, the point lies on the north south axis. At ninety degrees, the point lies beside the magnet. The calculator resolves the field into radial and angular parts. It also returns the combined flux density.
Force Options
Different objects feel magnetic effects in different ways. A test pole force uses pole strength times field. A moving charge uses the Lorentz relation. A straight wire uses current, length, field, and angle. A second magnet can be approximated with a dipole gradient along the axis. Torque is included for a small dipole placed in the local field.
Reading the Results
Results are estimates, not certified measurements. Real magnets have shape, grade, temperature, and nearby material effects. Iron, steel, and other ferromagnetic objects can distort the field. Very close to the magnet, the dipole model becomes less accurate. Use measured field data when safety or product ratings matter.
Practical Tips
Keep all distances positive. Use meters for scientific work. Convert centimeters and millimeters only when entering quick lab readings. Try several angles to map the field pattern. Compare axial and side positions. Use the CSV file for spreadsheets. Use the PDF export for reports. Record the magnet dimensions separately when you need a complete experiment note.
Better Use Cases
The tool can compare classroom magnets, small sensor positions, and simple actuator ideas. It can also show why force changes sharply with separation. Doubling distance can greatly reduce field and gradient effects. Enter a measured magnetic moment when available. Otherwise, use the example table as a starting point. Do not use the calculator for medical implants, lifting loads, or high energy equipment without expert testing. Save each run before changing units, angles, or probe settings during comparisons daily work.