Magnetic Field Calculator
Example Data Table
| Case | Current | Size value | Turns | Formula | Estimated field |
|---|---|---|---|---|---|
| Straight wire | 10 A | 0.05 m | 1 | B = μI / 2πr | 40 μT approx |
| Circular loop | 5 A | 0.10 m radius | 20 | B = μNI / 2R | 628 μT approx |
| Solenoid | 2 A | 0.30 m length | 500 | B = μNI / L | 4.19 mT approx |
Formula Used
This calculator uses common magnetic field equations for ideal conductors. For a long straight wire, the equation is B = μI / 2πr. Here, B is magnetic flux density, μ is permeability, I is current, and r is distance from the wire.
For a circular loop at its center, the equation is B = μNI / 2R. N is the number of turns. R is the loop radius. For a long solenoid, the equation is B = μNI / L. L is the coil length.
How to Use This Calculator
Select the magnetic field model first. Enter current with its unit. Add distance for a straight wire. Add radius for a circular loop. Add coil length and turns for a solenoid. Choose the output unit. Press calculate to view the answer above the form.
Use relative permeability when the core is not air. Air is usually close to 1. A magnetic core may need a higher value. Download the CSV file for spreadsheet work. Use PDF export for reports.
About Magnetic Field From Current
Current Creates a Magnetic Field
Electric current produces a magnetic field around a conductor. The field direction follows the right hand rule. Point your thumb along conventional current. Your curled fingers show the field direction. This idea helps in motors, coils, relays, transformers, and sensors.
Why Geometry Matters
The magnetic field depends on conductor shape. A straight wire spreads field lines around the wire. The field becomes weaker as distance increases. A circular loop concentrates field at the center. More turns increase the field because each turn adds flux. A solenoid gives a stronger and more uniform internal field.
Role of Permeability
Permeability describes how easily a material supports magnetic flux. Air and vacuum use a relative value near one. Iron and other magnetic cores may greatly increase field strength. Real materials can saturate at high fields. So practical designs may need test data.
Using the Result
Use tesla for engineering calculations. Use millitesla or microtesla for small fields. Gauss is also common in older references. Always check the selected unit before copying results. The calculator also shows the equation and converted values. This makes the answer easier to review and document.
Design Notes
Ideal formulas assume simple geometry and steady direct current. Nearby metal, alternating current, coil spacing, and core losses can change results. Use the answer as a strong estimate. For final hardware, compare with measurement or simulation.
FAQs
What does this calculator find?
It estimates magnetic flux density from current. It supports straight wire, circular loop, and long solenoid cases.
What unit is the main answer based on?
The base calculation uses tesla. The result can also be shown in millitesla, microtesla, or gauss.
What is relative permeability?
Relative permeability shows how much a material increases magnetic field compared with free space. Air is close to one.
Which model should I choose?
Choose straight wire for one conductor, loop for a round coil center, and solenoid for a long wound coil.
Why does distance reduce the field?
For a straight wire, field strength spreads outward. Greater distance gives a smaller field value.
Do more turns increase magnetic field?
Yes. In loop and solenoid models, field strength rises almost directly with the number of turns.
Is this suitable for AC current?
It is best for steady current estimates. AC fields may need frequency, waveform, skin effect, and core loss analysis.
Can I export my answer?
Yes. Use CSV for spreadsheet records. Use the PDF button for a quick printable report.