# Single-Layer Air-Core Coil Calculator

#### Approximate inductance (L) of a single-layer coil. Approximation is close for coils

whose length is equal to or greater than 0.4 times diameter at frequencies

below about 30 MHz. Note also that coils with length greater than about 5 times

diameter are often physically impractical (and a waste of wire). Turns must be

evenly spaced.

L(µH) = (d^{2}n^{2})/(18d + 40λ)

Where n is number of turns,

d is the diameter of the coil in inches and

λ is the length of the coil in inches

(inches = cm x .3937).

back

close

more calculators

maxmcarter.com