About this tool
Compute the equivalent resistance of two or three resistors connected in parallel.
Formula
1/R_eq = 1/R₁ + 1/R₂ + 1/R₃
Worked example
100 Ω ∥ 220 Ω → R_eq = (100·220)/(100+220) ≈ 68.75 Ω.
Notes
Equivalent resistance is always less than the smallest resistor. For series, just add: R_eq = R₁ + R₂ + …