Compute inductance from turns, diameter, and length. Review formulas, export results, and compare winding data. Build better inductor estimates for design checks and planning.
| Turns | Diameter | Length | µr | Approx Inductance |
|---|---|---|---|---|
| 20 | 2.00 in | 1.00 in | 1 | 21.05 µH |
| 40 | 3.00 in | 2.00 in | 1 | 107.46 µH |
| 60 | 1.50 in | 2.50 in | 10 | 637.80 µH |
Single-layer air-core Wheeler formula:
L (µH) = (r2 × N2) / (9r + 10l)
Where:
Adjusted inductance: Ladjusted = Lair × µr
Approx wire length: Wire Length = π × Diameter × Turns
Winding pitch: Pitch = Coil Length / Turns
Estimated DC resistance: R = ρL / A
This resistance is an engineering estimate for copper wire.
A coil inductor calculator helps engineers estimate inductance before building a winding. It saves time during circuit design. It also supports faster checks during prototyping. This page focuses on common single-layer coil analysis. You can enter geometry, wire size, and a core adjustment factor. The calculator then returns several practical design outputs.
The number of turns strongly affects inductance. Coil diameter also changes the magnetic field shape. Coil length influences how tightly the turns are spread. A larger relative permeability raises the final inductance. Wire diameter matters for pitch, packing, and resistance. These values help you balance size, inductance, and build quality.
The air-core inductance gives a baseline result. The adjusted inductance adds the selected permeability factor. Wire length helps estimate material usage. Pitch shows spacing between turns. Packing ratio warns when the winding may be too crowded. Estimated resistance supports early loss calculations. Aspect ratio and turns per inch help compare coil shapes.
This coil inductor calculator is useful for RF work, hobby electronics, filters, and general engineering analysis. It is also helpful for classroom demonstrations. You can compare different turn counts quickly. You can test larger diameters without hand calculations. You can also export the results for reports or design notes.
Use this tool for early estimation, not final certification. Real inductors can vary because of insulation thickness, winding spacing, core losses, and manufacturing tolerances. Measure finished coils with proper instruments when accuracy is critical. Even so, a reliable estimate improves planning. It reduces trial and error. It also helps you choose better winding dimensions from the start.
It is best for single-layer coil estimates based on winding geometry. It works well for air-core designs and for adjusted estimates using a relative permeability factor.
Microhenry is convenient for many small coils. Millihenry is useful when the value grows larger. Showing both units makes design review faster.
Relative permeability compares a core material to air. Air is 1. Higher values increase inductance. This calculator uses it as a simple adjustment factor.
No. It is an approximation based on coil diameter and turns. Real length can change with insulation thickness, lead length, and winding style.
Resistance affects copper loss and heating. It can also change efficiency and circuit behavior. Early resistance estimates help during design planning.
Packing ratio compares the total wire occupancy with winding length. A high value may suggest a very tight winding or an impractical layout.
Yes. The calculator converts entered diameter and length values into inches internally because the Wheeler equation is used in inch form.
Use it for engineering estimates and comparisons. Confirm final inductance with physical testing because real components vary with materials and build details.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.