Circuit Design / interactive engineering
Air-Core Coil Designer
Estimate a single-layer coil from its dimensions, inspect the winding, and check whether the turns fit.
Answer first
How do I use a air core coil inductance calculator?
Estimate a single-layer coil from its dimensions, inspect the winding, and check whether the turns fit. Enter the known values and inspect the result immediately. For example, Enter 20 turns, a 10 mm coil radius, and a 20 mm winding length to estimate the inductance and wire length. Use the output to check your reasoning or shortlist a design, then verify the units, assumptions, and real-world limits that apply.
Set the winding geometry
Inspect the winding
Select a component below or in the drawing. On small screens, scroll the schematic sideways to inspect it.
More turns increase inductance approximately with N². A wider coil increases it; a longer winding with the same turns generally reduces it. Diameter is measured through the wire centers, not the former alone. The drawing is schematic, with at most 30 visible loops.
Model, parts and limitations
Use radius r and winding length ℓ in inches; N is the turn count. The result is in microhenries.
Wheeler’s single-layer air-core estimate is a starting point, not a measured RF inductance. Insulation, lead length, winding spacing and nearby metal matter. Wire length excludes connecting leads. This does not calculate safe current or self-resonance.
Use nonmagnetic formers and confirm inductance with an LCR meter. Do not use this formula for ferrite cores, multilayer windings or PCB spirals.
Technical reference: H. A. Wheeler: Simple Inductance Formulas for Radio Coils (1928) ↗Design guide
Use the result with engineering context
Technical content reviewed
When this tool is useful
- Solving a air core coil inductance calculator task without repeating the arithmetic by hand
- Changing one input at a time to understand how it affects the result
What the result includes
- A result calculated from the values and units you enter
- A concrete reference case: Enter 20 turns, a 10 mm coil radius, and a 20 mm winding length to estimate the inductance and wire length.
What the model does not guarantee
- The result follows an idealized educational model and the values you enter
- It does not replace datasheet limits, tolerances, protection, thermal checks, measurement, or application-specific validation
Worked approach
Try a concrete set of values
Enter 20 turns, a 10 mm coil radius, and a 20 mm winding length to estimate the inductance and wire length. Change one input at a time, confirm the units, and compare the result with an independent calculation or relevant datasheet.
Common decisions
Questions engineers ask
What should I enter in the Air-Core Coil Designer?
Use known values in the units shown beside each field. Keep every input within a realistic range and convert units before comparing the result with another source.
Can I use the Air-Core Coil Designer result directly?
It does not replace datasheet limits, tolerances, protection, thermal checks, measurement, or application-specific validation
How should I verify the Air-Core Coil Designer result?
Repeat the worked example, check the units and assumptions, then compare the output with a second calculation, a trusted reference, or a measurement from the real system.
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