Series Resistance Calculator

About this calculator

Resistors wired in series share the same current, so their resistances simply add: R_total = R1 + R2 + R3 + R4 — however many resistors you chain end-to-end, the total opposition to current just keeps climbing.

Electronics hobbyists and students use it constantly when building circuits on a breadboard, since it's the fastest way to check a series combination against a target resistance — for LED current-limiting resistors, voltage dividers, or simply combining odd-value resistors from a parts bin to hit a value you don't have on hand.