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.

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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

kyle crater (Bethany Beach, Delaware)

I have a 6 speaker kit “3 in each tower” the kit says the impedence once assembled is 4 ohm. The tweeter is 8ohm, the mid 4ohm, and the sub 4 ohm. So if I wire the mid and the sub in series that would be 8 ohms, and then the tweeter in parallel that would bring me to 4 ohms. Is this correct. I used the calculator above for series/parallel and I place the mid ohm value “4 ohm” in speaker box one, the sub ohm value “4ohm” in speaker box 3, and the tweeter value “8ohm” in box… Read more »

Tim (mountlake terrace, washington)

Hi Geoff, I am trying to tackle an “out of the box” setup…I am wanting to use a car cd/dvd player with speakers that would connect to my television in my bathroom for when taking a long soaking bath. I already know and have purchased a converter for allowing me to power the cd/dvd player, my question is first can I use a waterproof “indoor” speakers or do I need to stay with car speakers or more likely marine style speakers. Also in dealing with ohms, if the cd/dvd player is rated for 4ohm speakers, can I still use 8ohm… Read more »

Darius (Latvia)

hello,
I have 4 speakers by 4 ohm and one subwoofer by 8ohm. My amp range is from 8 to 16
can i fix this ?

Bernardo Roldan (Hong Kong)

Hi Geoff,

I have an old set of LG speakers HX995TGW. The main unit is broken and i was wondering if i could reuse them and pair them with my Denon AVR 1800 receiver. Below is all i could get from their manuals.

Satellite & center speaker specs:
Type: 2 way 3 speaker
Impedence: 4ohms
Input power: 180W
Max. Input power: 360W

Receiver specs—
Rated output: stereo (2ch driven)
75W + 75W (8ohms w/ 0.05 T.H.D)
110W + 110W (6ohms w/ 0.7 T.H.D)
Dynamic power:
100W x 2ch (8ohms)
145W x 2ch (4ohms)
170W x 2ch (2ohms)
Output Terminals: 6-16ohms

Darren Quadros (Mumbai)

Hello Geoff… In my church I have an Power AMP – StudioMaster DJA 800 which has 2 channels and it give out @ 8ohms. I can connect 2 x 8 Ohms Speakers @165W RMS and @4ohms I can connect 2 Speakers @250W RMS. I mean connect 1 speaker on channel 1 and the other on 2 The problem is the folks have given me 12 speakers of Quest MS801W whose power handling is between 120 to 240W @8Ohms…so I have to connect 6 speakers to one channel and then other 6 to the other channel…. So if I do a… Read more »

Jordan

If I have 2 200watt 8 ohm speakers and an amp that will provide 400 watts rms @ 4 ohms x 1 then am I all good to wire in parallel?

Sandeep Kumar (Agra, India)

I have a speaker. On which neither the Ohm nor the watt have been written. So how do I know ohm and watt?

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