Find the total resistance of resistors wired in series — add as many as you need.

How to Use the Series Resistor Calculator

Enter a value for each resistor in the list — two rows to start, with buttons to add more or remove down to a single one. The total updates the instant any value changes.

Rtotal = R1 + R2 + ... + Rn

Series resistance is the one combination rule in this batch that needs no explanation beyond the formula itself: current has exactly one path to follow, so it has to push through every resistor in the chain one after another, and their resistances simply stack. A 100Ω and a 220Ω resistor in series behave, from the rest of the circuit's perspective, exactly like a single 320Ω resistor — nothing about the pair matters except their sum.

That straightforwardness is also why series resistance almost never gets its own dedicated calculator anywhere else — it's addition. This one exists mainly as the companion to the Parallel Resistor Calculator and the Series and Parallel Capacitor Calculator elsewhere on this site, for anyone building out a multi-part circuit calculation who wants both combination rules handled the same way, one field at a time.

Same guard as its parallel counterpart: a resistor value at or below zero doesn't correspond to a real component, so it's flagged rather than folded silently into the total.