What is Quantum meruit ? When does the claim on Quantum meruit arise?

1) Meaning of Quantum meruit :

     The phrase "Quantum meruit" literary means as much as earned or as much as is merited.   When a person has done some work under a contract, and the other party repudiates the contract, or some event happens which makes the further performance of the contract impossible, then the party who has performed the work can claim remuneration for the work he has already done. In simple words, where one party has partly performed the contract, while the other party has terminated the contract or he could not perform due to subsequent impossibility or illegality In such cases the person who has partly performed the contract can sue the other party for reasonable remuneration for the work done.

2) Definition of Quantum meruit :

        Anson: according to Anson " If the injured party, when the breach occurs, has already done, part, though not all of what he was bound to do under the contract, he may be entitled to claim the value of what he has done. In that case, he has to sue upon a Quantum meruit"  

3) Conditions:

       The plaintiff can institute an action for Quantum meruit if the following conditions are satisfied-

    1) It is available only if the original contract has been discharged.

    2)  The claim must be brought by the party is not in default.

4) Grounds of claim:

        The claim for Quantum meruit arises in the following cases...
       

i) When an agreement is discovered to be void- 

         When an agreement is discovered to be void, or when a contract becomes void, any person who has received any advantage under such agreement or contract is bound to restore it or to make compensation for it, to the person from whom he received it.

ii) When something is done without any intention to do so gratuitously-

         
      When a person lawfully does anything for another person or delivers anything to him, not intending to do so gratuitously, and such other person enjoys the benefit thereof, the latter is bound to make compensation to the former in respect of, or to restore, the thing so done or delivered.

iii)  When one party abandon or refuses to perform the contract

iv)  When a contract is divisible -

           When a contract is divisible and the party not in default has enjoyed the benefit of the part performance, the party in default may sue on Quantum meruit. But if the contract is not divisible for example where it requires complete performance as a condition of payment the party in default cannot claim remuneration on the ground of quantum meruit.

v) When there is an express or implied contract to render services but there is no agreement as to remuneration. In such a case, reasonable remuneration is payable. What is a reasonable remuneration is determined by the Court; and this reasonable remuneration is quantum meruit.

See also...

Promissory Note: Meaning Definition and Essentials of a Promissory note

Remedies For Breach of Contract | Law of Contract

The Doctrine of Novation, Kinds of Novation