Wheatstone Bridge Calculator

A Wheatstone Bridge Calculator is a tool — often digital or online — that helps determine the unknown resistance in a Wheatstone bridge circuit. The Wheatstone bridge itself is an electrical circuit used to precisely measure an unknown resistance by balancing two legs of a bridge circuit.

Here's a quick rundown of how the Wheatstone bridge works:

It consists of four resistors arranged in a diamond shape — two known resistances, one variable resistor, and one unknown resistor.
A voltage source powers the bridge, and a galvanometer (or detector) measures the balance between the two voltage dividers.
The formula for a balanced Wheatstone bridge is:

Where:

R1 and R2 are known resistances
R3 is a variable resistance (often adjustable)
Rx is the unknown resistance being calculated
When the bridge is balanced (the galvanometer shows zero current), you can solve for the unknown resistance:

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A Wheatstone Bridge Calculator simplifies this calculation — you just input the values of the three known resistors, and it calculates the unknown resistance. Some versions of these calculators might also help determine voltage differences, current through the bridge, or help analyze an unbalanced bridge.