Inductors in Series Calculator

Enter the inductance values of up to three inductors (in millihenries) to calculate total series inductance, unit conversions, and inductor balance metrics.

Created by Luis GonzalezLast updated: May 9, 2026

How to Use This Calculator

1
Enter Inductor L1 (mH)
Input the inductance of the first inductor in millihenries. Enter '0' if this branch is not used.
2
Provide Inductor L2 (mH)
Enter the inductance of the second inductor in millihenries. Enter '0' if this branch is not used.
3
Specify Inductor L3 (mH)
Input the inductance of the third inductor in millihenries. Enter '0' if this branch is not used.
4
Review the total series inductance
The calculator will display the total equivalent inductance in mH, H, and µH, along with dominance analysis.

Example Calculation

An electronics technician needs to find the total inductance of three inductors connected end-to-end in a series circuit.

10 mH

20 mH

30 mH

Results

60 mH

Tips

Additive Inductance

Unlike parallel connections, inductors in series simply add up. This makes it easy to achieve higher total inductance values than any single component offers.

Increase Energy Storage

Connecting inductors in series increases the total energy storage capacity of the inductive element, useful in applications like power supply filters or energy transfer systems.

Manage Voltage Drop

Each inductor in series will develop a voltage drop proportional to its inductance and the rate of current change. Consider this when designing circuits to ensure components can handle the expected voltages.

Calculating Total Inductance for Inductors in Series Circuits

In electrical engineering, combining inductors in series is a straightforward method to achieve higher total inductance values, essential for various filtering and energy storage applications. The Inductors in Series Calculator instantly computes the total equivalent inductance for up to three inductors, providing results in millihenries, Henries, and microhenries, along with analysis of individual inductor contributions. For instance, connecting a 10 mH, 20 mH, and 30 mH inductor in series results in a total inductance of 60 mH, a value critical for power supply filtering in 2025.

Advantages of Series Inductor Configurations

Connecting inductors in series offers several distinct advantages in circuit design. Primarily, it allows engineers to achieve a higher total inductance than any single component can provide. This is particularly useful in applications requiring significant current smoothing, such as in power supply filters where a large inductance is needed to suppress ripple, or in resonant circuits where a precise, high inductance value is necessary for tuning. Series configurations also increase the overall energy storage capacity of the inductive element, making them suitable for energy transfer applications. While the total inductance increases, designers must also consider the cumulative voltage drop across the series combination, ensuring that each inductor can handle the expected voltage swings and that the parasitic resistance of each component doesn't introduce excessive power loss. For example, in audio crossovers, inductors in series might be used to create a sharper low-pass filter, where the combined inductance directly impacts the filter's cutoff frequency.

The Additive Formula for Inductors in Series

When inductors are connected in series and are positioned far enough apart that their magnetic fields do not interact (i.e., there is no mutual coupling), their total equivalent inductance is simply the sum of their individual inductances. This makes the calculation very straightforward.

The formula for total inductance (L_total) is:

L_total = L1 + L2 + L3

Where:

L_total is the total equivalent inductance.
L1, L2, L3 are the inductances of the individual inductors.

This principle holds true for any number of inductors connected in series, as long as mutual inductance is negligible. If an inductor value is 0, it is effectively excluded from the series.

💡 To assess the performance of individual components in a larger system, our Transistor Bias Point Calculator can help analyze the operating conditions of active devices.

Summing Inductances: A Series Circuit Example

An electronics technician is assembling a custom power supply filter and needs to combine three inductors in series to achieve a specific total inductance. The inductors have the following values:

Inductor L1: 10 mH
Inductor L2: 20 mH
Inductor L3: 30 mH

To find the total inductance, the technician simply adds the values:

Sum the individual inductances:

L_total = 10 mH + 20 mH + 30 mH
L_total = 60 mH

The total inductance for these three inductors connected in series is 60 mH. This value is exactly what the technician needs for their filter, demonstrating the simple additive nature of series inductors. This configuration also means that the largest inductor (30 mH) contributes 50% of the total inductance, making it the dominant component in the series.

💡 For analyzing complex electrical systems, our Two-Port Network Parameter Calculator can provide insights into how components interact within a larger network.

Considering Mutual Inductance in Series Inductors

The simple additive formula for inductors in series assumes that there is no magnetic coupling between the individual coils. In practical circuits, if inductors are placed physically close to each other, their magnetic fields can interact, leading to what is known as mutual inductance (M). This mutual inductance can either add to or subtract from the total equivalent inductance, depending on the orientation of the coils.

Series-Aiding: If the inductors are oriented so their magnetic fields reinforce each other, the total inductance is given by L_total = L1 + L2 + 2M. This configuration effectively increases the overall inductance beyond the simple sum.
Series-Opposing: If the inductors are oriented so their magnetic fields oppose each other, the total inductance is L_total = L1 + L2 - 2M. In this case, the mutual inductance reduces the overall inductance.

For the additive formula to be accurate, engineers often ensure sufficient physical separation between inductors or use shielding to minimize mutual coupling. When significant coupling exists, specialized analysis and potentially different inductor types are required to account for these interactions, especially in high-frequency or high-power applications where precise inductance values are critical.

Frequently Asked Questions

What is the total inductance of inductors in series?

The total inductance of inductors connected in series, assuming no mutual coupling, is simply the sum of their individual inductances. This configuration increases the overall opposition to changes in current flow, making the equivalent inductance larger than any single inductor in the series.

When would you connect inductors in series?

Inductors are connected in series when a higher total inductance is required than what a single available component can provide. This is common in applications such as power supply filters, chokes, and energy storage circuits where a larger inductive effect is needed to smooth current or block specific frequencies.

How does mutual inductance affect series inductor calculations?

Mutual inductance significantly affects series inductor calculations if the inductors are magnetically coupled. If they are arranged to aid each other (series-aiding), the total inductance increases by 2M (where M is mutual inductance). If they oppose each other (series-opposing), the total inductance decreases by 2M. The simple sum formula applies only with zero mutual inductance.

Is connecting inductors in series similar to resistors in series?

Yes, connecting inductors in series is analogous to connecting resistors in series. In both cases, the total equivalent value (inductance or resistance) is the simple arithmetic sum of the individual component values, assuming no mutual coupling for inductors. This makes series calculations relatively straightforward for both components.