Parallel Resistor Calculator
Calculate total resistance of resistors connected in parallel
Enter values in ohms (Ω), separated by commas
How to Use This Calculator
Enter Resistor Values
Type the resistor values in ohms (Ω), separated by commas. Example: 100, 220, 470
Calculate
Click the button to compute total resistance when connected in parallel.
View Result
The result appears in ohms (Ω) or kilohms (kΩ) as appropriate.
Formula
1/R_total = 1/R₁ + 1/R₂ + 1/R₃ + ...
R_total = 1 / (1/R₁ + 1/R₂ + 1/R₃ + ...)
Special Case - Two Resistors:
R_total = (R₁ × R₂) / (R₁ + R₂)
Example:
Resistors: 100 Ω, 200 Ω, 300 Ω
1/R_total = 1/100 + 1/200 + 1/300 = 0.01 + 0.005 + 0.00333 = 0.01833
R_total = 1 / 0.01833 = 54.55 Ω
Frequently Asked Questions
Why does parallel connection reduce resistance?
Parallel resistors provide multiple paths for current, increasing conductance. As a result, total resistance is always less than the smallest resistor.
Do power ratings add up?
Power ratings do not add directly. Each resistor dissipates power based on its share of current and must be rated appropriately.
What about tolerance?
Resistor tolerances (e.g., ±1%, ±5%) affect the exact total. For precision networks, use matched resistors.