What does it mean to be paid in arrears?

Payment in arrears is the practice of compensating a service provider after the contract's obligations have been met. Arrears accounting denotes that payment will be made at the conclusion of a period rather than in advance. The term “in arrears” can be applied to both billing and paying. Billing in arrears means you bill customers after providing them with goods or services. Paying in arrears means you make a payment after receiving a good or service.