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Physics Calculators ▶ Parallel Resistor Calculator

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**Table of Content**

This parallel resistor calculator will calculate the equivalent and missing resistor value in a parallel combination of resistances. Enter the value of individual resistors connected in parallel and the tool will instantly figure out the missing one, with the steps shown.

Our online resistors in parallel calculator is very easy to use as it requires the following values to calculate results!

**Input:**

- 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
- If You Select Missing Resistance:
- Enter the value of the desired total resistance and number of resistances attached in a circuit
- Tap Calculate

**Output:**

- Equivalent or Missing resistor value, with the steps shown

**“A resistor whose both terminals are connected to the 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.

Our free parallel resistor calculator uses the following equation to calculate the resistor value in seconds:

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

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:

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

In a parallel circuit, each resistor connected has a particular potential difference (voltage drop) across its ends. 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 formula aforementioned.

Look at the figure below:

In this circuit, three resistors are connected in parallel to divert the path of the 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:

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

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

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

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

$$ \frac{1}{R_{eq}} = 1.6kΩ $$

This is the required answer and can also be verified by utilizing this parallel resistance calculator.

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

- 25kΩ
- 52kΩ
- 785kΩ
- 65kΩ

Using the resistors in parallel resistor formula:

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

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

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

$$ \frac{1}{R_{eq}} = 0.001kΩ $$

The addition of more resistors in an electrical network introduces new pathways for the currents to flow. This is why the addition of resistors is directly proportional to the increment in charge flow. This increment in the charge can also be determined using this parallel circuit calculator.

Two resistances will be considered in parallel connection if nodes at both 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.

If your goal comes up with the instant calculations of this equivalent resistor, using this parallel resistor calculator is the best option to go by.

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.

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 the short circuit are minimal. This keeps them running without 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 circuits with two batteries

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