Wheatstone Bridge Calculator

About this calculator

A Wheatstone bridge is a circuit of four resistors arranged in a diamond, used to precisely measure an unknown resistance by comparing it against three known ones. When the bridge is balanced — meaning no current flows through the galvanometer connecting the two midpoints — the unknown resistor Rx satisfies the ratio Rx = (R2 × R3) / R1, derived from the two voltage-divider legs being equal.

Electrical engineers and metrologists use the Wheatstone bridge configuration in strain gauges, load cells, and precision resistance-based sensors (including thermistors and RTDs for temperature measurement), because comparing against known references gives far higher accuracy than a direct ohmmeter reading. Enter the three known resistances to find the unknown one at balance.