OBJECTIVE: To develop an estimator for predicting successful extubation for an individual preterm infant. STUDY DESIGN: This was a retrospective study that included infants with birth weights ≤1250 g, who were admitted to a tertiary NICU over a 7-year period, received mechanical ventilation and had an elective extubation attempt within 60 days of age. Perinatal and periextubation characteristics were compared in the successful and failed extubation groups. RESULTS: Of 621 screened infants, 312 were included. Extubation succeeded in 73% and failed in 27%. Adjusted factors associated with successful extubation included greater gestational age, chronologic age, pre-extubation pH and lower pre-extubation FiO2, along with lower "peak" respiratory severity score in the first 6 h of age. CONCLUSIONS: We used readily available demographic and clinical data to create an extubation readiness estimator that provides the probability of extubation success for an individual preterm infant (http://elasticbeanstalk-us-east-2-676799334712.s3-website.us-east-2.amazonaws.com/).