Resistors in Parallel

How to use this calculator

List each parallel branch's resistance and unit, then add or remove rows as needed; the equivalent resistance updates in real time. Parallel resistors combine with the reciprocal rule, 1/R = 1/R₁ + 1/R₂ + … + 1/Rₙ, so the tool inverts each value, sums them, and inverts the total — which is why the result is always smaller than the lowest individual resistor (more paths for current means less opposition).

What the value means in a circuit

Every parallel branch has the same voltage across it, but the current splits among the branches in inverse proportion to their resistance (a smaller resistor carries more current). The equivalent resistance is the single value the source sees, so it sets the total current (I = V/R_eq) and total power. Parallel combinations are used to share load current, set precise lower values, create multiple taps, and improve reliability — understanding the reciprocal relationship is key to predicting how adding or removing a branch changes the whole circuit's draw.