There are two laws associated with Kirchhoff.
Kirchhoff's Current Law (KCL):
The sum of all the currents at any node in a circuit equals zero.
A common sign convention must be applied around any node in order to use this law. Typically, current that leaves a node is considered positive and current that enters a node is considered negative.
So for the following schematic:
i1 + i2 – i3 – i4 = 0
Kirchhoff's Voltage Law (KVL):
The sum of all the voltages around any closed path in a circuit equals zero.