How to use the Resistance Calculator
- Choose series/parallel or wire resistance.
- Enter resistor values (4.7k, 1M and similar are fine) or the wire details.
- Read the result.
What does this tool do?
Resistors in series simply add up. In parallel, the reciprocals add, so the total is always less than the smallest resistor.
A wire's resistance depends on its material's resistivity, its length and its cross-sectional area: longer and thinner means more resistance.
Why use it?
- Series and parallel at once.
- Understands k and M suffixes.
- Wire resistance for common metals.
The formula
Series: R = R₁ + R₂ + …
Parallel: 1/R = 1/R₁ + 1/R₂ + …
Wire: R = ρL ÷ A
Privacy
The calculation happens instantly in your browser. The numbers you enter are not sent to our servers or saved. There's no account to create and nothing to install.
Last reviewed by the M2Toolkit team.