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Parallel Resistor Calculator

Parallel Resistor Calculator

The calculator will use a parallel resistance formula to find the parallel load resistance of the circuit.



Desired Total Resistance:


Resistor 1:


Resistor 2:



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Are you feeling a hurdle to calculate equivalent or missing resistance of a parallel circuit? Stop worrying and start using our free parallel resistor calculator that does exactly the same. Yes, you would be amazed by the fact that this calculator will let you compare the resistances in an electrical circuit to compute the total resistance of the circuit required to run it smoothly.

Coming to the point now, let’s move forward to know more about circuit’s resistance.

Stay with it!

What Is Resistance?

“The opposition to the current flow within a circuit is known as the resistance of circuit”


The basic symbol used to denote resistor is as under:

Parallel Resistor:

“A resistor whose both terminals are connected to same node is known as the parallel resistance”

In an electrical network containing parallel resistors, the current of the whole circuit would be equivalent to the sum of all the currents flowing through each single resistor. and when its come to compute its value, the free online parallel resistor calculator is the only option you are left with.

Parallel Resistance Formula:

In a parallel circuit, each resistor connected has a particular potential difference (voltage drop) across its ends. And it causes a lot of voltage to drop at each and every node of the electronic circuit network. That is why it becomes very crucial to compute how much loss is there in it as a whole. And this could be calculated only if you use the following parallel resistors in parallel formula:

$$ R_{eq} = \frac{V}{I_{total}} = \frac{V}{(\frac{V}{R_1} + \frac{V}{R_2} + \frac{V}{R_3} + … + \frac{V}{R_n})} $$

By taking LCM of the above expression, it can be reduced to simplest form as:

$$ R_{eq} = \frac{1}{(\frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} + … + \frac{1}{R_n})} $$

And the most simplified notation of the above expression can be written as:

$$ \frac{1}{R_{eq}} = \frac{1}{R_1 + R_2 + R_3 + … + R_n} $$

The free parallel resistor calculator also takes into consideration the following formula to compute the equivalent resistance of the whole electrical network.

How To Find Resistance In a Parallel Circuit?

Most of the time, the query”how to solve complex parallel circuits” comes into mind when dealing with complicated electrical networks. The only answer to this problem is to employ either parallel resistor formula for this online parallel resistor calculator.


Look at the figure below:

In this circuit, three resistors are connected in parallel to divert the path of current, thereby decreasing its potential. Assuming the ideal load attached to it, how to calculate resistance in a parallel circuit given?


Using parallel resistance formula:

$$ \frac{1}{R_{eq}} = \frac{1}{R_1 + R_2 + R_3 + … + R_n} $$

$$ \frac{1}{R_{eq}} = \frac{1}{10 + 2 + 1} $$

$$ \frac{1}{R_{eq}} = \frac{1}{10} + \frac{1}{2} +\frac{1}{1} $$

$$ \frac{1}{R_{eq}} = 0.1 + 0.5 + 1 $$

$$ \frac{1}{R_{eq}} = 1.6kΩ $$

Which id the required answer and can also be verified by utilising this parallel resistance calculator.

Illustration # 02:

How to find total resistance in a parallel circuit having following resistors connected in parallel?

  • 25kΩ
  • 52kΩ
  • 785kΩ
  • 65kΩ


Using the resistors in parallel formula:

$$ \frac{1}{R_{eq}} = \frac{1}{R_1 + R_2 + R_3 + … + R_n} $$

$$ \frac{1}{R_{eq}} = \frac{1}{25 + 52 + 785 + 65} $$

$$ \frac{1}{R_{eq}} = \frac{1}{927} $$

$$ \frac{1}{R_{eq}} = 0.001kΩ $$

How Parallel Resistor Calculator Works?

You just need to follow steps below to calculate equivalent resistance of the parallel circuit by using our online resistors in parallel calculator:


  • From the first drop-down list, select what resistance you are willing to find

If You Select Equivalent Resistance:

  • Add the values of resistances in designated fields. You can also add up to 30 resistances
  • After you are done, hit the calculate button

If You Select Missing Resistance:

  • Enter the value of the desired total resistance and number of resistances attached in a circuit
  • Now tap the calculate button


The parallel circuit calculator does the following calculations within a matter of seconds:

  • Calculate equivalent and missing resistance in a parallel circuit


What Happens When You Parallel the Resistor?

Addition of more resistors in an electrical network introduces new pathways for the currents to flow. This is why addition of resistors is directly proportional to the increment in charge flow.

How Do You Know If Two Resistors are Parallel?

Two resistances will be considered in parallel connection if nodes at both the ends of the resistors are the same. In such a case, the resistances R_1 and R_2 will be parallel such that (R_1||R_2). And if there is another total resistance R_3, then it will be in series with the parallel combination of these two resistors.

Is Voltage Same In Parallel?

Yes, in a parallel circuit, the overall voltage of the network is always the same. You can better understand the voltage and current relationship of any circuit or a single conductor by using the ohms law calculator.

What Is the Law of Resistance?

The law of resistance states that:
“The resistance of a conductor is directly proportional to the length of the conductor, keeping the temperature and physical condition constant”.

What Is Called Conductance?

Conductance is a special property of materials such as of metals or non-metals due to which electric current flows through the circuit network. It is denoted by the symbol G.

Why Do We Prefer Parallel Connection at Home?

Parallel connections allow currents to be delivered without any distortion to the appliances running. And according to Joule’s law, when there will be no heat loss, the chances of short circuit are minimal. This keeps them running without burning.


Parallel resistances allow the voltage across the electrical networks at the same potential. And that is why, this particular connection in a circuit keeps the devices away from burning.


From the source of Wikipedia: Series and parallel circuits, Parallel circuits, Combining conductances, Notation, Applications

From the source of Khan Academy: Resistors in series and parallel, Resistor networks, resistor circuit with two batteries

From the source of Lumen learning: Resistors in Series and Parallel, Combinations of Series and Parallel, Practical Implications