Calculate the inductance of a single-layer air-core helical coil (solenoid).
Coil Dimensions
in
in
Electrical Properties
Enter dimensions to calculate inductance
Quick Reference
NNumber of Turns
dCoil Diameter (inches)
lCoil Length (inches)
LInductance (microhenries)
Overview
This calculator uses Wheeler's formula for the inductance of a single-layer air-core helical coil. It's a widely used approximation for RF and electronics design.
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Pro Tips
Diameter (d) is measured from wire center to wire center.
Length (l) is the total winding length of the coil.
Wheeler's formula is most accurate when length is greater than 0.4 times the radius.
Units: Enter dimensions in inches or millimeters (conversion handled).
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Fun Facts
"Helical coils are fundamental to radio transmitters and receivers."
"The magnetic field inside a long solenoid is remarkably uniform."
"Harold Wheeler published this simplified formula in 1928, and it remains a standard today."
