How this calculator works
Uncoupled inductors in parallel share terminal voltage. Their inverse inductances add, giving a total below the smallest member. Mutual coupling changes this result, so the coils must be sufficiently separated or arranged to make coupling negligible.
Formula
1/Xeq = sum(1/Xi); Xmissing = 1/[1/Xtarget - sum(1/Xknown)].
Worked example
Uncoupled 2 H and 3 H inductors in parallel give 1.2 H. A 2 H coil needs another 2 H in parallel to reach 1 H.
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Frequently asked questions
What does the component count mean?
It counts known components. Missing-component mode adds one more, so a single known component is allowed.
Why is a requested total rejected?
A passive positive component must change the total in the direction allowed by the connection. Equality would require a zero or infinite ideal component.
Are real component tolerances included?
No. Enter measured values or calculate tolerance extremes separately. Ratings and parasitic effects require a separate check.