Formula and calculation method
Series = sum(R). Parallel = 1/sum(1/R); a zero-ohm parallel branch makes the equivalent zero.
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
How to use resistor calculator
- Set Resistances (Ω). The example below uses 100, 200, 300.
- Select Calculate to update the result. Reset restores the illustrated inputs. Copy, print or download your own result if you need a record.
Worked example
Example inputs
- Resistances (Ω)
- 100, 200, 300
- Series (Ω)
- 600
- Parallel (Ω)
- 54.54545455
Factors affecting your result
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
Changing resistances (ω) changes the scenario being evaluated. Adjust one input at a time when comparing results, keep a copy of the assumptions, and compare values using the same unit and period. A precise arithmetic result does not make an uncertain assumption precise.
Frequently asked questions
How does the resistor calculator work?
Series = sum(R). Parallel = 1/sum(1/R); a zero-ohm parallel branch makes the equivalent zero.
What inputs does Resistor Calculator need?
Enter resistances (ω). Choose values that correspond to the same situation and measurement convention.
How should I interpret the resistor calculator result?
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
Are my resistor calculator inputs uploaded?
No. The calculation runs in this browser. Favorites, recent tool names, theme and formatting preferences may be saved locally, but calculation inputs are not sent to a calculation server or stored by this website. Shared links do not include entered values.
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