Online symptoms checkers are increasingly used, but formal validation of these tools is lacking. This survey of 329 patients’ experience using an artificial intelligence-assisted online symptom checker found that patients most commonly used the tool to understand the causes of their symptoms (76.3%), determining whether (33.2%) or where (20.7%) to seek care. Patients who had previously experienced a diagnostic error were more likely to use the tool to determine where they should seek care than patients who had not previously experienced diagnostic error.