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).

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 Calculatoras 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

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?

Hi Shawn, I’m more technical rather than being an audiophile, so others may have a different opinion to me based on different criteria. So, technically speaking, I would probably set the multiplier links to x2 (the default). With all three sets of 8 ohm speakers connected in parallel the total speaker impedance would be 2.6 ohms. Then multiply this by 2, and the minimum load impedance the amp will see would be 5.43 ohms (when the switch volume controls at are full volume). So connecting to the amp at 4 ohms would probably be a good fit. Obviously, with less… Read more »

Geoff-

Thanks so much. I missed that simulator when I was searching earlier. My speaker selector (sdb4.1) manual says the default multiplier is x4 so I think if I am using your simulator correctly I am safe using the 8 ohm tap. That is what I have been using these last two weeks.

Thanks so much for your time.

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!

Hi Ryan, Let me start by saying I’m not a car audio person, so I don’t claim any expertise at all in this area. However the basic physics still hold. The amp looks a solid unit and will work into any load above 1 ohm. Obviously it produces more power at 1 ohm (1100 watts), but it will work fine at 2 ohms (700 watts) on the sub output. The Phoenix Gold subs look, their documentation is quite limited. Normally a dual coil sub will allow you to wire the two coils in series, giving you a 4 ohm sub.… Read more »

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.

Hi Will,

With 6 leads, I’m assuming you have 6 speakers, that is 3 pairs, each pair in different rooms.

Therefore you will need a 4 zone speaker selector switch with impedance protection. See my article on connecting 4 speakers for more info.

Geoff

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.

Hi Mike,

I assume you have a stereo amp, and therefore only need to connect 4 speakers to each side.

This being the case, you could connect all four in parallel. This will give a load impedance of 2 ohms for each amp. Which according to your comment the amp is designed for.

The 800 watts from the amp will be distributed evenly across all four speakers, so each speaker will see 200 watts when the amp is at full power.

hope this helps

Geoff

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?

Hi,

I would hazard a guess by saying it would out just slightly less. But it would all depend on the design and build of the amp.

I doubt you could discern the change in output.

Geoff

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 »

Hi Simon, I think I understand what you are trying to do. First up, you are correct in that the A and B outputs are the same. They are in parallel and simply provide a convenient way to connect and switch two sets of speakers. So for calculation purposes they are in parallel. So, lets say you use the left channel for the tweeters. You would effectively have two 8 ohm speakers in parallel, giving a total load impedance of 4 ohms, which should be fine for the amp. Each tweeter will share the power from the amp 50/50. Now… Read more »

Many thanks Geoff. Yes it was the already parallel amp that made me think I had my calculation wrong which you confirmed and it would be as you say. I have various equipment doing nothing so I’m experimenting to learn about about ohms effects on wiring and active type designs and how much power I need to run the speakers. After I posted my question I had an even crazier idea. The full set up is like this and it’s a bit complicated haha iPhone as source outputting mono. Into pioneer DJM250 DJ mixer with left input on channel 1… Read more »

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 »

Hi Trey,

Your amp will run fine with a total load of 12 ohms, it just wont work as hard or be quite as loud as running into 4 or 8 ohms.

However if you have six 8 ohm speakers, won’t you have just 3 speakers on each channel? If this is the case, then you could run each set of three in parallel. This will give each of the dual amps a load of 2.7 ohms. Since you amp will work into a load of 2 ohms or more, then this should be fine.

hope this helps

Geoff

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?

Hi John,

Running a speaker of any impedance in parallel with a 6 ohms speaker will result in a total impedance less than 6 ohms, so best not to run any other speakers in parallel. Wiring them in series will be safe for the amp.

Geoff

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 »

Hi Josh, You are discovering why speaker manufacturers charge so much for the designs. It is not easy. I’m an installed, not a speaker designer, so I can’t help too much I’m sorry. From the little bit that I know, I’s suggest your current crossover frequencies are not right for the speakers. Every speaker has its optimum frequency range and would need to get those frequencies. I also suggest that by wiring the three in series as you have, that none of them are getting enough power to let you hear the mids and highs. You 4 ohm speakers are… Read more »

Thanks for the reply Geoff, I understand the power difference between the speakers, and actually used 4 ohm speakers to split the power like that on purpose.. as the 8 ohm speakers are much bigger and can handle considerably more power than the smaller full range and tweeter.. So by using the 4 ohm smaller speakers.. it sends more power to the bigger speakers that can handle it.. based on the wattage rating, it’s actually pretty close to optimal for each speaker. (based on your calculator above) My question is more regarding the wiring procedure to hook up a crossover… Read more »

Hi Josh,

As I’m not a speaker designer I may not be able to help much.

However I think your basic logic is OK, and should not hurt anything to give it a try. You could then play around with different caps to see if you hear any difference.

My thought is it should work, but the cross-overs will not be tight. But that is only my guess as I don’t pretend to know much about speaker designing.

Geoff

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?

Hi John,

Yes, connecting both pairs in parallel is the safest way.

Geoff