Physics

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Magnetic Force Between Wires Calculator.

Calculate force per unit length between two parallel currents.

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01

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Results update as you type.

Force per length: 0.00016 N/m

Force per length

0.000000N/m

Results update automatically as you type.

Use Cases

Physics homework and exam prep

Quickly verify calculations for problems involving parallel current-carrying wires, a common topic in electromagnetism courses.

Example: Check the force per unit length for two wires with 5 A and 10 A separated by 0.02 m.

Engineering design of busbars and cables

Estimate mechanical stresses on parallel conductors in electrical systems to ensure safe spacing and support.

Example: Evaluate the force per meter between two busbars carrying 1000 A each with 0.1 m separation.

Frequently Asked Questions

What does this calculator compute?
It computes the force per unit length between two parallel wires carrying electric currents, based on the currents (in amperes) and the separation distance (in meters). The result is in newtons per meter.
How is the force direction determined?
The calculator provides the magnitude of the force per unit length. The direction depends on the current directions: parallel currents attract, antiparallel currents repel. This tool does not determine direction.
What units are used for the inputs?
The first and second currents must be entered in amperes (A), and the wire separation must be in meters (m). The output is force per unit length in newtons per meter (N/m).

Tips & Common Mistakes

Tips

  • Ensure both currents are entered in amperes; if you have milliamps, convert to amps by dividing by 1000.
  • Wire separation must be in meters. Convert centimeters to meters by dividing by 100.
  • The calculator assumes the wires are infinitely long and parallel; for finite wires, results are approximate.
  • Use the result to compare forces for different current values or separations to understand the inverse relationship with distance.

Common Mistakes to Avoid

  • Forgetting to convert units: entering currents in milliamps or separation in centimeters without conversion leads to incorrect results.
  • Confusing force per unit length with total force: this calculator gives force per meter, not the total force on a finite wire length.
  • Assuming the calculator accounts for wire radius or material: it only considers the given currents and separation, ignoring wire thickness and permeability.

Last updated: August 13, 2026