Series & Parallel Resistance Calculator
Total resistance of any number of resistors, in series or parallel.
How it works
In series, resistances add: R = R1 + R2 + ... In parallel, conductances add, so 1/R = 1/R1 + 1/R2 + ...
Two consequences are worth internalising. A parallel combination is always smaller than its smallest member, so parallelling is how you reach values below what you have in the drawer. And a series chain is dominated by its largest member, so adding small resistors to a big one barely moves the total.