Example Data Table
| Frequency |
Parallel Inductors |
Equivalent Inductance |
Total Reactance |
Use Case |
| 1,000 Hz |
10 mH, 22 mH |
6.875 mH |
43.1969 Ω |
Audio filter check |
| 5,000 Hz |
4.7 mH, 10 mH, 15 mH |
2.635514 mH |
82.7971 Ω |
Branch comparison |
| 60,000 Hz |
100 µH, 220 µH |
68.75 µH |
25.9181 Ω |
Switching circuit estimate |
Formula Used
For each ideal inductor branch:
XL = 2πfL
For ideal inductors in parallel:
1 / Leq = 1 / L1 + 1 / L2 + 1 / L3 + ...
XL,total = 2πfLeq
The same result can be written as:
1 / XL,total = 1 / XL1 + 1 / XL2 + 1 / XL3 + ...
For optional series resistance, the calculator also uses:
Zi = R + jXLi
Ztotal = 1 / Σ(1 / Zi)
The ideal equation assumes uncoupled inductors and no winding resistance.
How To Use This Calculator
- Enter the operating frequency.
- Select the correct frequency unit.
- Enter two or more inductor values.
- Select the default inductance unit.
- Add source voltage if current and power are needed.
- Add series resistance if real coil loss matters.
- Enter tolerance to estimate a reactance range.
- Press Calculate and review the result above the form.
- Use CSV or PDF export for your records.
Parallel Inductive Reactance Guide
A parallel inductive circuit has two or more coils connected across the same source. Each branch receives the same voltage. Current divides between branches according to each branch reactance. A lower reactance branch carries more current. A higher reactance branch carries less current. This calculator helps compare those branches clearly.
Why Parallel Reactance Matters
Parallel inductors appear in filters, tuned circuits, motor controls, power supplies, and matching networks. The total inductive reactance is not found by simple addition. Parallel paths increase total current. So the combined reactance becomes smaller than the smallest single branch reactance. This result can surprise new learners. It is normal for parallel reactive circuits.
What The Calculator Evaluates
The tool accepts frequency and several inductance values. It converts each value to henries. Then it calculates branch reactance with the standard inductive reactance equation. Next, it combines the branches with the reciprocal parallel rule. It also reports equivalent inductance, branch admittance, optional current, and stored magnetic energy. These extra values help with design checks.
Ideal And Practical Branches
In an ideal circuit, each inductor has no winding resistance. Real coils have resistance, core loss, tolerance, and temperature effects. The optional resistance field lets you estimate a practical branch impedance. It does not replace lab testing, but it gives a stronger planning result. Use measured values when accuracy is important.
Reading The Result
The total reactance is shown in ohms. Since the circuit is inductive, the impedance sign is positive imaginary. A larger frequency creates larger reactance. A larger equivalent inductance also creates larger reactance. Adding more parallel branches usually lowers equivalent inductance and total reactance. Review branch currents before choosing wire size or source ratings.
Design Tips
Use consistent values. Avoid mixing estimated and measured coils in one calculation. Check frequency units before submitting. Very small inductance values can produce low reactance at audio frequencies. Very high frequencies may need parasitic capacitance models. For RF work, layout and lead length matter. For power work, heating and saturation matter. Treat this result as a design estimate, then confirm it with proper instruments. Keep safety margins generous. Document every assumption before parts are ordered. Compare results at the lowest and highest expected operating frequencies too.
FAQs
What is total parallel inductive reactance?
It is the combined opposition to AC current from inductors connected in parallel. It is measured in ohms. For ideal branches, it is lower than the smallest branch reactance.
Why does total reactance fall in parallel circuits?
Parallel branches give current more than one path. More current flows for the same voltage. Since reactance equals voltage divided by current, the total reactance becomes lower.
Can I enter different inductance units together?
Yes. You may type units beside values, such as 10mH or 220uH. Values without typed units use the selected default unit.
Does the calculator include coil resistance?
Yes. Enter series resistance per branch. The ideal result still appears, and the practical impedance result uses complex branch impedance.
Is this calculator valid for coupled inductors?
No. The main formula assumes uncoupled inductors. Magnetically coupled coils need mutual inductance terms. Use a circuit model for transformer-style coupling.
Why is frequency required?
Inductive reactance changes with frequency. Higher frequency gives higher reactance for the same inductance. Zero frequency gives no inductive reactance.
What does tolerance range mean?
It estimates total reactance when all inductors shift by the entered tolerance. It is a simple worst-direction range, not a statistical tolerance analysis.
Can I use this for RF circuits?
Yes, for first estimates. At high frequency, parasitic capacitance, layout, leads, and core behavior can change results. Confirm RF designs with proper measurements.