Series Resistance Calculator Formula

Understand the math behind the series resistance calculator. Each variable explained with a worked example.

Formulas Used

Total Resistance

total_resistance = r1 + r2 + r3

Variables

VariableDescriptionDefault
r1Resistor 1(Ω)100
r2Resistor 2(Ω)220
r3Resistor 3 (0 if unused)(Ω)330

How It Works

Series Resistance

Resistors in series carry the same current, and their resistances add directly.

Formula

R_total = R1 + R2 + R3 + ...

The total resistance is always greater than the largest individual resistor.

Worked Example

Three resistors in series: 100, 220, and 330 ohms.

r1 = 100r2 = 220r3 = 330
  1. 01R_total = R1 + R2 + R3
  2. 02R_total = 100 + 220 + 330
  3. 03R_total = 650 Ω

Ready to run the numbers?

Open Series Resistance Calculator