<h3>Objectives:</h3> To determine the utility of a clinical calculator to predict the benefits of chemotherapy and outcomes in women with early stage high risk ovarian cancer. <h3>Methods:</h3> Data from 2006-2015 was abstracted from the National Cancer Database. All patients had stage I, grade 3; stage IC, stage II, or clear cell carcinoma. Using a Cox regression model, based on demographic, surgico-pathologic, and laboratory characteristics, a clinical score was developed. Propensity score matching was used to reduce bias between patients who did and did not receive chemotherapy. The clinical calculator was validated by both bootstrapping and in an independent validation set. <h3>Results:</h3> Of 8,289 patients with early stage high risk ovarian cancer, 6,990 (84%) did and 1,299 (16%) did not receive chemotherapy. Patients who underwent chemotherapy had a 5-year overall survival (OS) of 85% vs 80% in those without treatment (p<0.001). On univariate analysis, significant prognostic factors included older age (HR 1.71), larger tumor size (HR 1.13), malignant ascites (HR 1.32), decreased number of lymph nodes examined (HR 1.38), higher stage (HR 1.70), carcinosarcoma (HR 3.35), high grade histology (HR 2.23), lymphovascular invasion (HR 1.44), and elevated CA-125 (HR 1.17). To better define those who may have an increased benefit from chemotherapy, we designed a clinical calculator capable of dividing patients into low (n=2,518), moderate (n=3,361), and high-risk (n=2,410) groups with associated 5-year overall survival of 92%, 86% and 73%. Using the calculator, chemotherapy was associated with an improved 5-year overall survival in the high (58% to 75%, p<0.001) and moderate risk groups (82% to 86%, p=0.001), but did not benefit the low risk patients (92% to 92%, p=0.13). There was an interaction between increasing score and improved patient outcomes with the administration of chemotherapy (p<0.001). <h3>Conclusions:</h3> Our results suggest a clinical calculator can help direct chemotherapy decision making for women with high risk early stage ovarian cancer.