## Series resistor formula

The formula to calculate the equivalent resistance of resistors connected in series is **R = R _{1} + R_{2} + ... + R_{n}**.

Where **R** is the equivalent or total resistance value of the series circuit and **R _{1}, R_{2}, ...R_{n}** is the resistance value of each resistor.

## How to calculate series resistor

When you connect resistors in series, each resistor shares the same current with a different voltage. Depending on each resistor's resistance value, the voltage between the individual resistor can be found using Ohm's law formula.

So the total voltage between the power source is the sum of all voltages combined.

Alternatively, we can calculate the total voltage using the equivalent resistance connected to the power source.

We can now find the equivalent resistance using the following formula.

Example: Calculating equivalent resistance of a series circuit

What is the total resistance of a connection consisting of three resistors: ${R_1} = {8.00 Ω}, {R_2} = {12.00 Ω},$ and ${R_3} = {21.00 Ω}$?

To find an equivalent resistance of the series resistors in the connection, use the following formula and follows by entering the given values.

Therefore,

The total resistance of the current connection with three resistors is ${R} = {41\ Ω}$.

## How to use the calculator

Our parallel resistor calculator calculates the equivalent resistance in real-time as you enter or change each resistor's value. It is responsive and works on either desktop or mobile.

The calculator starts with two input boxes for two resistors, and you can add as many as you like by using the **Add Resistor **button.

You can also change the individual resistance unit from **Ω** (ohms) to **mΩ** (milli-ohms), **kΩ** (kilo-ohms), and **MΩ** (mega-ohms) by using the drop-down menu next to each box.

The result will appear in two places. The **Result **section will show only the final value of the equivalent resistance of the parallel circuit, while the **Calculation **section will show you the detailed steps.