Solenoid Magnetic Field Calculator
Enter the number of turns, solenoid length in metres, and current in amperes.
A QUICK WALKTHROUGH
How to use this tool
- Enter the stated measurements in the specified units.
- Select Calculate to evaluate the formula.
- Review the result and the model limitations.
Formula and scope
For a long solenoid, B = μ₀NI/L at its centre. This uses μ₀ = 4π × 10⁻⁷ H/m as the conventional approximation. Independent reference: OpenStax University Physics Volume 2, Solenoids and Toroids (https://openstax.org/books/university-physics-volume-2/pages/12-6-solenoids-and-toroids). Turns N is a positive integer, L > 0 m; current may be signed. Assumes vacuum or air permeability and neglects core materials and end effects.
GOOD TO KNOW
Common questions
What assumptions does this use?
Long-solenoid centre approximation for vacuum or air; no core material or end effects.
Are values uploaded?
No. The calculation runs locally in this browser.