The calculator below can be used to determine the total equivalent resistance of up to four (4) resistors in series.

Resistors are in series when there is a single current path that travels through each resistor in order.

Resistors are in parallel when there are multiple current paths that may have different values of resistance.

One of the most important quantities is the equivalent resistance of the circuit.

Even though resistors may come in complex configurations, we can model the circuit as a single resistor. This resistor will have the value of the equivalent resistance of the whole circuit.

## Formula for Resistors in Series

Resistors in series add their values of resistance simply, making it easy to calculate their equivalent value. You can think of resistors in series as essentially functioning as a single resistor. In fact, every part of the current path through the circuit adds some amount of resistance (even wire) so that the whole circuit can be considered to be a large resistive element.

To find the total resistance in a series circuit (or a single branch of a parallel circuit), you just add up the resistances of everything in the circuit (or branch).

R_T = R_1 +R_2+R_3+...+R_N

If this calculator, didn’t help, check out our other calculators for electronics or our comprehensive tutorials!