Series and Parallel Resistance Calculator
Calculate equivalent resistance, source current, and branch values for a simple two-resistor DC network.
Enter circuit values
Circuit values
About this calculator
Calculate equivalent resistance, source current, and branch values for a simple two-resistor DC network. Use measured or manufacturer-specified values where available.
Series circuits share one current across components; parallel branches share the same voltage. The calculator reports both branch voltage and current for the selected connection.
Method and assumptions
For series resistors, equivalent resistance is the sum of branch resistances. For parallel resistors, the reciprocal of equivalent resistance is the sum of reciprocal branch resistances. Source current follows I = V ÷ R; branch values follow the selected circuit connection.
The model assumes ideal resistors with constant resistance at steady state. It excludes component tolerance, temperature rise, wiring resistance, reactive components, transients, and protective-device selection.
FAQs
Can I use this for AC circuits?
No. This calculator models ideal, steady-state DC resistors. It does not model reactance, phase angle, harmonics, or AC load behavior.
Does the result check component ratings?
No. Compare calculated voltage, current, and power with component datasheets and application limits before selecting or operating equipment.
Sources
Ideal resistor relationships from Ohm’s law and the DC power equation.