Microservices enable a fine-grained control over the cloud applications that they constitute and thus became widely-used in the industry. Each microservice implements its own functionality and communicates with other microservices through language- and platform-agnostic API. The resources usage of microservices varies depending on the implemented functionality and the workload. Continuously increasing load or a sudden load spike may yield a violation of a service level objective (SLO). To characterize the behavior of a microservice application which is appropriate for the user, we define a MicroService Capacity (MSC) as a maximal rate of requests that can be served without violating SLO. The paper addresses the challenge of identifying MSC individually for each microservice. Finding individual capacities of microservices ensures the flexibility of the capacity planning for an application. This challenge is addressed by sandboxing a microservice and building its performance model. This approach was implemented in a tool Terminus. The tool estimates the capacity of a microservice on different deployment configurations by conducting a limited set of load tests followed by fitting an appropriate regression model to the acquired performance data. The evaluation of the microservice performance models on microservices of four different applications shown relatively accurate predictions with mean absolute percentage error (MAPE) less than 10%. The results of the proposed performance modeling for individual microservices are deemed as a major input for the microservice application performance modeling.