Kirchhoff's Current Law (KCL) Calculator

Kirchhoff's Current Law states that the algebraic sum of currents entering and leaving a node in an electrical circuit must equal zero. In other words, the total current flowing into a node equals the total current flowing out of that node.

Currents flowing into a node are considered positive, while currents flowing out of a node are considered negative. You can choose any direction as your reference, but be consistent throughout your calculation.

A negative result means the actual current direction is opposite to what you assumed. If you assumed the current was flowing into the node but got a negative value, the current is actually flowing out of the node.

Yes, KCL applies to any node (junction point) in an electrical circuit where two or more conductors meet. It's a fundamental law that must be satisfied at every node for the circuit to be in steady state.

Use consistent units throughout your calculation. This calculator uses Amperes (A) as the default unit. You can also use milliamperes (mA) or microamperes (μA), just ensure all values use the same unit.

KCL calculations are theoretically exact for ideal circuits. In practice, small measurement errors or component tolerances may introduce minor discrepancies, but the law remains highly accurate for circuit analysis.

This calculator works for DC circuits and AC circuits when using RMS values or instantaneous values at a specific time. For complex AC analysis with phase relationships, you'll need phasor calculations.

While this calculator supports up to 6 currents, you can apply the same principle manually: sum all currents flowing into the node and subtract all currents flowing out. The result should equal zero, or give you the unknown current.