Speakers in Parallel Calculator

The calculator below is useful in determining the total impedance of speakers in parallel. It also calculates how the power is shared between the speakers. If all the speakers have the same impedance, the calculation is relatively simple. 

Simple Impedance Calculation for Speakers in Parallel

If all the speakers in parallel have the same impedance, then the calculation is easy. Simply divide the impedance by the number of speakers in parallel.

Example 1: Four 8 ohm speakers in parallel: 8 divided by 4 = 2 ohms.

Example 2: Two 4 ohms speakers in parallel: 4 divided by 2 = 2 ohms.

Not so Simple Calculations for Speakers in Parallel

For calculations involving speakers in parallel with different impedance, the following formula is required (it can be used with speakers of similar impedances too).

\large{Imp_{Total}}=\frac{1}{\frac{1}{Imp_1}+\frac{1}{Imp_2}+\frac{1}{Imp_3}+ ...}

If you have a calculator with 1/x button then this calculation is not too difficult. If you don’t have that function on your calculator, or if you don’t like formulas, check out the calculator below.

Using the Calculator

The calculator can be used for 2, 3 or 4 speakers wired in parallel. 

Simply type the impedance of each speaker into the white boxes (or use the drop-down values). Use N/A for unused speakers in this calculator. The total impedance will be calculated for the entered speakers.

Also calculated for each speaker is its percentage share of the amplifier’s output power. This is useful as power sharing is a consideration when using speakers with different impedance.

“Power Differential” is the final calculation. This calculates in dB (decibels) the power level difference between the highest and lowest power as it is shared across the speakers. This shows the power level difference when using speakers with different impedance.

Amplifier Power Calculator

The bottom section of the calculator helps in matching the speaker combination with your amplifier. This is not necessary if you only want to know the total impedance and/or the power ratios.

However if you are connecting these speakers to your amplifier, it may be helpful to input the amplifier power and the associated speaker impedance. In the specifications for your amplifier, it should say something like:

Amplifier power: 80 watts continuous average power @ 4 ohms (2 channels driven, THD 0.08%, 20Hz-20kHz)

This tells you the maximum continuous power the amplifier will deliver into a 6 ohm load is 80 watts. In the calculator below, for this example, you type in 80 for the power and 6 for the impedance. Be aware, some specifications state RMS power rather than continuous power. These are effectively the same.

The calculator will display the effective power of the amplifier for the calculated total impedance of the series speakers. Also displayed (under each speaker’s power %) is the actual maximum power the amplifier will supply each connected speaker. A comment on the suitability of the calculated total impedance for your amplifier is also provided.

Download Calculator
as Excel File
Prices in US$

Note: the calculated output power for the amplifier is based on a theoretical “ideal” amplifier. In practise, your amplifier may produce slightly more power.

Further Reading

This calculator will help you understand the total speaker load on your HiFi amplifier. For a better understanding of this and what to do about it, read the articles How do I Connect Multiple Speakers to my HiFi Amplifier and How to wire four HiFi speakers or How to connect 2 speakers to one amplifier or watch the video in the article Understanding Speaker Impedance.Also see How Multiple Speakers Share Power for further details about the percentage power calculations. For more details about the effective amplifier power at higher impedance loads, see How Impedance Changes Amplifier Power.

Please Note: all these calculations are for connecting manufactured speakers (boxes). They are not used when building your own speaker boxes and connecting multiple speakers in a cabinet using a crossover circuit. A crossover splits the signal into different frequencies for each of the speakers and makes the total impedance calculation complex (as impedance is frequency dependent). That is why speaker designers get the big money, and as installers we benefit from their expertise.

If you need further advice on connecting speakers (boxes) in parallel, please read the FAQs before submitting your question. You may also find an answer in the comments below.

Please Note: During the Covid-19 crisis I'm very busy with a number of streaming projects, and have very limited time to attend to this website.. I'm currently over a week behind in answering questions and may not get to them in a hurry. Sorry for any inconvenience.

Disclosure: If you buy through this Amazon USA link Geoff receives a small commission from each sale.
European and Australian readers can use the links on the side panel - Thanks for the support

Shawn (San Francisco, CA)

I have been googling for an answer and stumbled on your website. I have a McIntosh MC2205 200w amplifier with autoformers. I am using a Russound SDB-4.1 speaker selector, also with autoformers, connected to three pairs of 8ohm speakers.

I don’t necessarily use all three pairs at one time but often do. Which tap in the amplifier should I connect the selector to? 2, 4 or 8?

Ryan (phx,az)

I have (2) 2ohm phoenix gold ti312d2 speakers and need to get them to a 1ohm load to run on my phoenix gold elite.5.? Did I buy the wrong speakers? My amp is only stable to 1ohm not .5ohm!

Will Adair (Calgary)

Hello Geoff,
Working on Sundays?
Here is what I have run across.
I have 6 speakers all connected with a single lead (+ / -) running back to the head end.
All the connections are behind the drywall some where cant see them at all.
in testing i attached my tone generator to one of the 6 speakers and got the generated tone at each speaker through the toner.
I have a 50 watt 8 ohm amplifier.
do you know what needs to happen to get the proper impedance at the amplifier.

Mike (Ann Arbor)

Hi Geoff,

Love the site!

I have eight 8ohm speakers(250) I want to connect to an amp. The amp is rated 800@ 2ohms, 550@ 4ohms, and 325@ 2ohms. If not possible, what would be the correct speakers/watts to get for this amp. Also do each speaker get the same amount of watts or does the amp distribute the watts evenly the more speakers you connect. Your help would be great.

Mr. Mitchell (Euless Texas)

Hi Geoff. Great site you have. So my question is I have an amp that puts out 1500 watts Rms@ 1ohm. If I’m running it at 1.33 ohms how much rms power would you figure it puts out? Then same question for 1700 watts rms@1ohm running at 1.33 ohms. What would its rms power output?

Simon (UK)

Hi Geoff Absolutely fantastic site you have. Great work! I appreciate this will probably sound a little strange but here goes. I have a Technics SU-V300 amplifier. It has A and B speaker selection. This I think has 27w per channel but I’m unsure if that’s per speaker channel when running in A and B mode or just with only A or B. Running A or B only it can do 4-16 ohm loading. Running A and B it can do 8-16 ohm loading. My speakers I have are 2 centre channel speakers. Focal CC700S and Focal CC700V. They are… Read more »

Trey Muhlenkamp (Coldwater, United States)

Hi Geoff, I am trying to wire 6- 8ohm speakers as efficiently as possible. They are all in my garage, and I have a Crown CDi 1000 amp (its 2 channel, 275W @ 8 ohms per channel). Speakers are handling 80 watts RMS. I used the series/parallel calculator and it gave me 45.8 watts power for each speaker. But it says if I wire them all in series/parallel the total load impedance for the amp is 12 ohms. Also total impedance for first 3 and last 3 speakers is 24 ohms. What does this mean? The amp can handle 2,… Read more »

John Renzo Maniago (Mexico, Philippines)

2 6-ohm speakers
2 unknown impedance speakers.
Amp capacity is 6 ohms to 18 ohms

What’s the safest? Wiring them in series or parallel?


I am attempting to build a set of custom speakers, and was hoping to achieve a 4 way design using an 8 ohm bass driver wired in parallel to a series of 3 smaller speakers starting with an 8 ohm mid bass, 4 ohm full range, and 4 ohm tweeter. According to your calculator, this would give me a total of 5.7 ohms… I have the bass driver hooked up to a 500hz low pass filter (the speaker jack type), and the other 3 speakers run off of the full range signal. My questions.. is how can I hook up… Read more »

John Renzo Maniago (Mexico, Philippines)

Hi Geoff!
I have a 2-channel HiFi amp with 190watts that can handle 6-16ohms output impedance. I have 2 speakers with 6-ohms impedance. Now, I want to add the additional 2 speakers (no specifications stated) that my uncle lend me, is it safe if I just wire them in series?