Since 2013 the Passive House Institute US has seen a significant increase in the design, construction and certification of multifamily passive buildings. Many first multifamily passive buildings, from 6-to-57-unit developments, have been completed and occupied since then. Monitored performance data are now available. This presentation will report on a detailed comparison of modeled performance predicted by passive design tools and actual measured performance data for three case study projects while occupied and under operation. The question of how well the currently used passive modeling tools, algorithms and underlying modeling assumptions match the measured performance in the field will be answered as well as if the anticipated overall energy and carbon reduction goals in these projects have been met.