Resistor Series/Parallel Calculator
Total resistance for two resistors in series or parallel.
Reviewed by James Whitfield · How we check our maths
Your values
ⓘ Live results
Results
- Series total
- 690 Ω
- Parallel total
- 149.86 Ω
Quick answer
Series: R = R1 + R2. Parallel: R = (R1 x R2)/(R1 + R2).
The formula
R_series = R1+R2, R_parallel = R1R2/(R1+R2)
Worked example
Worked example
Using the values the calculator loads with.
Inputs
- Resistor 1220 ohms
- Resistor 2470 ohms
Result
- Series total690 Ω
- Parallel total149.86 Ω
How to use the Resistor Series/Parallel Calculator
- 1Enter the two resistor values.
- 2Series resistance simply adds up.
- 3Parallel resistance is always lower than the smallest individual resistor.
Frequently asked questions
Why is parallel resistance lower?
Adding a parallel path gives current more routes to flow, reducing overall resistance.
How do I combine three or more resistors?
Combine two at a time, or for equal parallel resistors divide the value by the count.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error