Demurrage in vessel chartering is the period when the charterer remained in possession of the vessel after the period normally allowed to load and unload cargo. By extension, demurrage refers to the charges that the charterer pays to the ship owner for its delayed operations of loading/unloading.

 Officially, demurrage is a form of liquidated damages for breaching the laytime as it is stated in the governing contract (the charter party). The demurrage sometimes causes a loss to the seller as it increases cost of the total freigh.