Resistor Combination Calculator for a Target Resistance

How to use the resistor combination calculator

Enter the target resistance and select its unit. Choose an E-series, the maximum number of resistors, the permitted component range and the actual component tolerance, then select “Find resistor combinations.” Start with the Best match and compare the alternatives when component count, topology or available values matter.

What is a resistor combination calculator?

It solves the inverse of an equivalent-resistance calculation. You provide the resistance your design needs; the finder searches standard parts and returns networks whose equivalent resistance is closest to that target.

Why combine standard resistor values?

Calculated design values often fall between preferred E-series values. Combining parts can help when setting analog gain, building bias networks, tuning a prototype, calibrating a circuit or replacing an unavailable value.

The closest mathematical result is not always the best practical design. Also consider tolerance, board space, noise, power rating and part availability.

E12 vs E24 vs E96

E12, E24 and E96 provide 12, 24 and 96 preferred values per decade. A denser series usually offers a closer nominal match, while a smaller series may be easier or cheaper to source. The calculator suggests ±10%, ±5% and ±1% respectively as starting tolerances, but the actual part tolerance is your choice.

Series, parallel and mixed resistor combinations

The search covers one resistor; two resistors in series or parallel; and four three-resistor families: all series, all parallel, one resistor plus a parallel pair, and one resistor in parallel with a series pair. It does not search bridge or arbitrary mesh networks.