Inductance Of Air Core Inductor Calculator
Instantly calculate the inductance of an air-core coil using diameter, turns, and coil length. Accurate, fast, and perfect for RF and electronics design.
Inductance of Air Core Inductor Calculator:
Inductance of air core inductor Calculator calculates the inductance of an air core inductor coil with a single layer, depending on its physical size. Type in the diameter of the coils, the number of turns, and the coil length, and automatically calculate inductance in microhenries (µH) with the Wheeler formula or the Nagaoka correction to calculate inductance more accurately.
The tool is primarily suitable for the design of radio-frequency (RF) coils, chokes, and resonant circuits in cases where the magnetic cores are not present. It also computes the inductance per turn, total circuits of wire, and gives recommendations on the best ratio of coil aspect. This calculator enables engineers and students to find the size of inductors very quickly when used in oscillators, filters, and impedance matching networks.
Inductance of Air Core Inductor Tools formula
To calculate the inductance of an air-core inductor, use Wheeler’s formula:
Formula: \( L(\mu H) = \frac{r^{2}N^{2}}{9r+10\iota} \)
where 𝑟 is coil radius (in inches), 𝑙 is coil length (in inches), and 𝑁 is the number of turns. This calculator automates the process — enter your coil’s diameter, turns, and length to get inductance in µH, plus coil geometry details such as winding length, aspect ratio, and recommended spacing for accurate RF design.
Work & Installation — Input to Output Summary
Work: Computes inductance of a single-layer solenoid or air-core coil using empirical formulas (Wheeler, Nagaoka). Optionally converts between metric and imperial units and estimates coil resistance and wire length.
Installation:
- Add calculator HTML and CSS to your website.
- Link the JavaScript file that runs the inductance formulas.
- Optionally embed with for easy inclusion.
Input:
- Coil diameter (D)
- Coil length (L)
- Number of turns (N)
- Wire diameter (optional)
- Units (mm/inch)
Output:
- Inductance (µH)
- Inductance per turn²
- Wire length
- Coil aspect ratio (L/D)
- Turn spacing
- Recommended coil configuration
Example:
Testing and Final Adjustments
Verify known cases of inductors and datasheets with the calculator to verify its accuracy. Compare the results with the formula of Wheeler and Nagaoka of the various coil geometries (short coils, long solenoids). Test accuracy in changing inches to millimeters. To improve UX, one should add some warnings in case the coil length is not long enough (L < 0.4D) to follow simple formulae. Include hover tooltips with each variable description, and formula reference, and an option of metric/imperial. Check the results of output formatting (e.g., L 4.23 mH) and dissipation of power in the case of the wire resistance. To make the final adjustments: make sure that it is responsive, labeled accessible, le and the final option of copying the results or exporting them as a CSV. Minimizes the JavaScript loading time and adds unit tests of arbitrary coil geometry to ensure accuracy within 2 per cent.
Frequently Asked Questions - Inductance Of Air Core Inductor Calculator:
What is an air-core inductor?
An air-core inductor uses no magnetic core; its inductance depends solely on coil geometry and number of turns.
Which formula does this calculator use?
It uses Wheeler’s formula L(µH) = (r²N²)/(9r + 10l) for single-layer coils and optionally Nagaoka correction for accuracy.
What inputs are required?
Coil diameter, coil length, and number of turns; optionally wire diameter for spacing and resistance.
What are the units of inductance?
The output inductance is given in microhenries (µH).
Can I use metric units?
Yes — enter dimensions in millimeters or inches; the calculator automatically handles conversions.
Is this valid for multi-layer coils?
No — it’s optimized for single-layer air-core coils; multi-layer inductors need more complex formulas.
How accurate is the result?
Accuracy is within about ±2% for L/D between 0.3 and 3; beyond that, results are approximate.
Does wire thickness affect inductance?
It slightly affects coil spacing; include wire diameter for best accuracy.
Can I calculate coil resistance too?
Yes — when wire diameter and material are entered, the tool estimates total wire length and DC resistance.
Where is this used?
Air-core inductors are used in RF circuits, filters, resonant tanks, and oscillators where core losses must be minimized.
