Created By : Vaibhavi Kumari

Reviewed By : Phani Ponnapalli

Last Updated : May 10, 2023

The Parallel Resistor Calculator is a simple tool that may be used to calculate the equivalent resistance in a parallel circuit. Simply fill in the required information in the tool and press the calculate button to get equivalent resistance in no time.

Choose a Calculation
Resistor 1 (R1)
Resistor 2 (R2)

What is meant by Parallel Resistance?

If the voltage between the resistors is the same, the circuit is said to be linked in parallel. Current is distributed out in these circuits and then combines when they meet at a common location. Resistance is measured in Ohms. 1 Ohm is defined as the electrical resistance between two places that results in a current of 1 Ampere when applied to a potential difference of 1 volt.

Parallel Resistance Formula

The formula for calculating equivalent resistance in a parallel circuit is as follows: 1/R = 1/R₁ + 1/R₂ +... + 1/Rn

  • Where, R = Equivalent Parallel Resistance
  • R₁, R₂,... Rn are the resistances of separate resistors, numbered 1, 2, 3,...n

How to Calculate Parallel Resistance?

To determine Parallel Resistance, use the simple steps outlined below. The following is the sequence in which they occur

  • First, find out the resistances of the individual resistors.
  • Then, for each resistor, determine its reciprocal value.
  • Using the formula 1/R = 1/R₁ + 1/R₂ +... + 1/Rn, add up all the reciprocal values of the separate resistors.
  • After substituting the known numbers, simplify the equation to obtain the comparable resistance value in no time.

Applications of Parallel Resistance

Resistors connected in series are equivalent to a single resistor with a resistance equal to the sum of each individual resistor. Parallel resistors, on the other hand, produce an equivalent resistance that is always lower than the total resistance of each individual resistor. This makes sense when you consider it: A particular amount of current flows when you apply voltage across a resistor.

You've effectively established a new path for greater current to travel through when you connect a second resistor in series with the first. The overall current coming from the power source will always be somewhat higher than the current passing through the single resistor, regardless of how large the second resistor is. If the total current is larger, the overall resistance must be lower as well.

For more concepts check out to get quick answers by using this free tool.

Examples on Resistors in Parallel

Question 1: In the circuit below, find current I and the current flowing through each of the resistors.

The three resistors are connected in series and act as a resistor with resistance. The request is given by

1/R = 1/100 + 1/400 + 1/200

Multiply all terms by 400

400 R = 4 + 1 + 2

R = 400/7 Ω

The main current I is given by;

I = 7/R = 7/(400 / 7) = 49/400 A

To determine the current flowing through each resistor, we now apply Ohm's law.

I1 = 7 / 100 A is the current flowing through the 100-ohm resistor.

I2 = 7 / 400 A is the current flowing through the 400-ohm resistor.

I2 = 7 / 200 A is the current flowing through the 200-ohm resistor.

Check that the total of the three currents above equals the current I = 49 / 400 A as an exercise.

FAQs on Parallel Resistor Calculator

1. How do you calculate parallel resistance?

The following formula can be used to calculate total resistance in a parallel circuit: 1/Rt = 1/R₁ + 1/R₂ + 1/R3 +.... Current will continue to flow in all of the parallel pathways if one of them is broken.

2. What is the difference between parallel and series?

A series circuit has the same amount of current flowing through all of the components. In parallel circuits, on the other hand, the components are connected in parallel, causing the circuit to split the current flow.

3. What makes resistors parallel?

If the terminals of two resistors are connected to the same two nodes, they are in parallel. The overall equivalent resistance is less than that of the smallest parallel resistor.

4. How does current divide in parallel circuits?

The current in a parallel circuit splits into several branches before recombining and returning to the source. When a current splits into two branches, the current in each branch equals the current before the split.

5. In a parallel circuit, which bulb will fuse first?

In a series configuration, the bulb with the higher resistance will be the first to fuse since it can tolerate more voltage.