Toroid Inductor Online Calculator

Toroid Inductor Calculator

Iron core & ferrite — inductance factor and geometry methods

RF / Magnetics

A Using Inductance Factor (A_L)

Calculate Turns (N)

L :

A_L :

N turns

Calculate Inductance (L)

A_L :

N :

Formulae

Iron Powdered: L = A_L·N² / 10,000 [µH] | N = 100·√(L_µH / A_L)

Ferrite: L = A_L·N² / 1,000,000 [mH] | N = 1000·√(L_mH / A_L)

B Using Toroid Geometry

Calculate Turns (N)

µ_i:

N turns

A_e cm²

l_e cm

Calculate Inductance (L)

µ_i:

A_e cm²

l_e cm

Formulae

Inductance: L = (4π·N²·µ_i·n·A_e) / l_e [nH]

Effective Length: l_e = π(D−d) / ln(D/d) [cm]

Effective Area: A_e = 0.5·n·(D−d)·h [cm²]

D = outer dia (cm) · d = inner dia (cm) · h = height (cm) · µ_i = initial permeability · n = stacked cores