Series & Parallel Resistor Calculator
Add up to 10 resistors and calculate the equivalent resistance for series or parallel circuits. Supports Ω, kΩ, and MΩ units.
R1
R2
R3
Equivalent resistance
Enter at least 2 resistor values
R1
R2
R3
Reference formulas
Series resistors
Req=R1+R2+ … +Rn
Total resistance is the direct sum of all resistors. Each component adds to the overall circuit resistance.
Parallel resistors
1Req=1R1+1R2+ … +1Rn
The reciprocal of total resistance equals the sum of reciprocals of each resistor. Equivalent resistance is always less than the smallest resistor in the circuit.