There are two laws of Kirchoff. They are very important in circuit analysis. The first law is known as kirchoff's current law and the second one called kirchoff's voltage law
Kirchoff's Current Law
Kirchoff's Current Law states that The sum of the current entering a node(the point where two or more circuit elements meet) is equal to zero or the sum of current leaving the node is zero or the sum of current entering a node is equal to the sum of currents leaving the node.The first law is in fact a statement of the conservation of the charge in a circuit.
Kirchoff's Second Law
Kirchoff's Voltage Law states that the sum of the voltages\potential differences in a loop or mesh equals zero. This law is a statement of the conservation of energy, because 1 volt is in fact energy expended\dissipated per unit charge.