Background: The quality of recovery-15 (QoR-15) is a patient-reported outcome measurement measuring QoR after surgery and anesthesia. The scale is arbitrary and ranges from 0 to 150. We aimed to classify the QoR-15 score into four severity classes; excellent, good, moderate, and poor recovery. Materials and methods: Data from one prospective observational cohort study and two randomized clinical trials were merged and comprised 276 adult patients with an American Society of Anesthesiologists class of I-III undergoing acute laparoscopic surgery for suspected appendicitis. Merged data were split into a “training” set and a “validation” set. Optimal cutoff points for classifying the QoR-15 into excellent, good, moderate, and poor recovery were identified in the “training” set. The four severity classes according to the QoR-15 score were validated in the “validation” set using prespecified hypotheses. Results: The QoR-15 scores for excellent, good, moderate, and poor recovery were 136-150, 122-135, 90-121, and 0-89, respectively. A better severity class of recovery based on the QoR-15 score measured repeatedly six times over 30 d was associated with an increased chance of resuming recreational and occupational activities (P < 0.001). Patients with a better severity class of recovery on the first postoperative day had a lower incidence of postoperative complications within 30 d of surgery (P = 0.001). Conclusions: After surgery and anesthesia, patients can be classified as being in poor, moderate, good, or excellent recovery based on the QoR-15 score.