A method, a device, and a non-transitory storage medium are described in which a network slice usage service is provided. The network slice usage service may allow a network device to obtain a network slice usage value of a network slice. The network device may be implemented as a network data analytics function (NWDAF). The network slice usage value may be provided by an access and mobility management function (AMF). The network device may calculate a network slice load value based on the network slice usage value. The network device may also provide the network slice load value to other network devices of a core network, such as a network slice selection function (NSSF) and/or a policy control function (PCF).