Enter the inductance values for up to six parallel inductors and select your preferred unit (H, mH, μH, nH, or pH). The calculator applies the reciprocal-sum formula to return the equivalent parallel inductance along with a visual breakdown of each inductor's contribution. Works for any number of inductors from two to six — just leave unused fields blank.
Equivalent Parallel Inductance
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Number of Inductors
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Smallest Inductor Value
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Unit
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For inductors in parallel, you use the reciprocal-sum formula: 1/L_eq = 1/L₁ + 1/L₂ + ... + 1/Lₙ. Compute the sum of the reciprocals of each inductor value, then take the reciprocal of that sum to get the equivalent inductance. The result is always smaller than the smallest individual inductor.
When inductors are in parallel, they share the total current, which reduces the overall opposition to changes in current. This is analogous to resistors in parallel — adding more parallel paths always lowers the effective inductance, so the equivalent value will always be less than the smallest inductor in the group.
When two identical inductors, each of value L, are connected in parallel, the equivalent inductance is exactly L/2. More generally, n identical inductors each of value L connected in parallel give an equivalent inductance of L/n.
Using the reciprocal formula: 1/L_eq = 1/10 + 1/10 + 1/10 = 0.3 mH⁻¹, so L_eq = 1/0.3 ≈ 3.333 mH. This equals 10 mH divided by 3, confirming the rule for identical inductors in parallel.
Yes. Real inductors have a small but non-zero DC resistance due to the resistance of the wire used to wind the coil. This is called the DC resistance (DCR) or winding resistance. For most AC circuit calculations the resistance is ignored, but in precision or high-current applications it must be accounted for.
Inductance is measured in Henries (H). Common sub-units are millihenries (mH = 10⁻³ H), microhenries (μH = 10⁻⁶ H), nanohenries (nH = 10⁻⁹ H), and picohenries (pH = 10⁻¹² H). This calculator lets you enter all values in the same chosen unit and returns the result in that unit.
No. The equivalent inductance of inductors in parallel is independent of the order in which they are connected. The reciprocal-sum formula is commutative and associative, so rearranging the inductors does not change the result.
In a series circuit, inductances simply add: L_eq = L₁ + L₂ + ... + Lₙ, so the equivalent is always larger than any individual value. In a parallel circuit, the reciprocals add, making the equivalent always smaller than the smallest individual inductor. Series connections increase inductance; parallel connections reduce it.