Resistor Series & Parallel Calculator
Calculate total equivalent resistance for any number of resistors connected in series or parallel.
1. Enter your numbers → 2. Check the answer → 3. Read the steps before you trust it
Equivalent Network Resistance
3 resistors in series
Step-by-Step Engineering Calculation
- 1Series Connection:
Formula & Theory
Calculates total network equivalent resistance for multi-resistor combinations.
Variable Definitions
- R_total:
- Equivalent Resistance (Ohms (Ω)) – Total effective network resistance
- R1, R2...:
- Branch Resistors (Ohms (Ω)) – Individual resistor values
Worked Engineering Example
Parallel Divider Network
Three parallel resistors: 100Ω, 220Ω, and 470Ω.
- Resistors: 100, 220, 470 Ω
- Mode: Parallel
Key Assumptions
- •Pure linear resistive elements.
Limitations & Safety Scope
- •Does not calculate parasitic lead inductance at RF frequencies.
Frequently Asked Questions
Why is parallel resistance always lower than the smallest resistor?
Adding a parallel branch creates an additional conductive path for electrons, which increases total circuit conductance and reduces overall resistance.
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Educational & Reference Notice: This calculator provides technical estimates based on standard physical formulas. Actual electrical installation, protective device sizing, and conductor selection must be verified against the applicable electrical code (NEC, IEC, CEC) by a licensed electrician or qualified professional engineer.