Background <p>Optimal Woven EndoBridge (WEB) sizing is crucial for successful implantation. We used three-dimensional (3D) software, Siemens Aneurysm Analysis v. VD30B, to determine the potential of WEB device-aneurysm volume (DAV) ratios in predicting post-treatment occlusion status.</p> Methods <p>We retrospectively reviewed 35 unruptured intracranial wide-neck bifurcation aneurysms treated using the WEB. The study evaluated the association between the DAV ratio and aneurysm obliteration during follow-up. The primary aim of the study was to determine the optimal DAV ratio for predicting occlusion status following WEB treatment.</p> Results <p>The success rate of treating all unruptured aneurysms with the WEB was 100%. The median duration to final follow-up was 365 ± 184.0&#xa0;days with all 35 patients having a mean modified Rankin Scale score of 0. One (2.9%) patient experienced a transient ischemic attack with hemiparesis perioperatively. A follow-up angiography revealed complete occlusion (WEB Occlusion Scale [WOS] A and B) in 25 (71.4%) of 35 patients and WOS C and D in 10 (28.6%) of 35. The median DAV ratio significantly differed between the groups. The median DAV ratios were 0.97 in the complete occlusion group and 0.84 in the WOS C and D group, respectively (<i>p</i> = 0.002). A receiver operating characteristic curve produced an area under the curve of 0.76 (confidence interval: 0.56–0.96). The optimal DAV ratio cut-off and the highest Youden index for complete occlusion was 0.90.</p> Conclusion <p>Calculating DAV ratios using 3D software may help improve the rate of complete occlusion following WEB treatment.</p>