PURPOSE: Clinical management for unruptured intracranial aneurysms (UIA) is controversial and requires professional knowledge which is the main reason that patients have difficulty in making decisions. The purpose of this study is to develop a tool that aids healthcare consumers in making optimal shared decisions with decision analysis. METHODS: The decision model and relevant data were derived from published literature. A web-based decision analytic tool was designed to provide a systematic guide for patients to understand favorable treatment options, intrinsic uncertainty, and critical factors for decision making. Twenty-nine testers evaluated content appropriateness, usability and clinical usefulness of the tool. RESULTS: The decision analytic tool has been successfully implemented and evaluated. Testers generally judged the web-based decision analytic tool as functional and useful. Acceptance rate for decision analysis was higher in nonhealthcare professionals than health care professionals. CONCLUSIONS: Our decision analytic tool was well accepted especially by healthcare consumers. The tool enables UIA patients to enhance their knowledge and understanding toward optimal shared decision making and can be an alternative "structured informed consent tool".