Resistor Calculator

Series or parallel equivalent resistance for two resistors.

Resistor Calculator helps you series or parallel equivalent resistance for two resistors. Enter r1 (ω) and r2 (ω), review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Resistor calculator does Resistor Calculator is built for everyday questions — shopping, home, travel, hobbies, and tech. Series or parallel equivalent resistance for two resistors. You enter r1 (ω) and r2 (ω), then Simple Calculators computes the result instantly. Defaults are chosen to be easy to read — change any field to match your situation. How the math works Choose the Configuration, then enter R1 (Ω) and R2 (Ω) in ohms. In series (one after the other) the total is R1 + R2. In parallel (side by side) the total is R1 × R2 ÷ (R1 + R2), which is always smaller than the smaller resistor. The calculator also shows how the voltage (series) or current (parallel) is shared between the two. The formula: Series: total = R1 + R2; parallel: total = R1 × R2 ÷ (R1 + R2). R1 and R2 are resistances in ohms (Ω).