1. IntroductionSpecialty contractors – usually called subcontractors – perform the majority of work on commercial construction projects. It is common for a typical construction project to use dozens of subcontractors, with 80 to 90 percent of the work on most construction projects in the United States being performed by subcontractors (Hinze and Tracey 1994). . The performance of the subcontractor is essential to the success of the project (Arditi and Chotibhongs 2005; Gray and Flanagan 1989). Typically, subcontractors must perform work on multiple projects simultaneously (Sacks 2004), but with limited resources, each subcontractor strives to maximize their workload at any time for optimal use of resources (Mathews et al. . Thus, subcontractors’ work activities are subject to individual resource constraints (Kim and Paulson 2003). During construction, changes frequently occur and conflict with subcontractor capacity constraints, causing immediate reallocation of resources (O'Brien and Fischer 2000). As a result, resource allocation due to frequent changes poses a crucial challenge for contractors. Due to frequent changes, contractors typically change resources between projects and work to understand potential impacts after resource reallocation. Unfortunately, most existing tools are overly complicated and provide limited support for reallocation of resources across projects, especially for rapid what-if analysis scenarios for decision making. This leads to the use of manual resource allocation methods. In response, this article presents a multi-project resource allocation tool. A test case with a variety of projects and task durations is presented to demonstrate the tool.2. Literature Revi...... middle of article ......lulu, HI., United States, 593-599. Sturts Dossick, C. and Schunk, T.K. (2007). “Method for controlling subcontractor schedules.” Journal of Construction Engineering and Management, 133(3), 262-265. Tommelein, ID, Riley, DR, & Howell, GA (1999). “Parade Game: Impact of Workflow Variability on Business Performance.” Journal of Construction Engineering and Management, 125(5), 304-310.Turner, J. and Speiser, A. (1992). “Program management and information system requirements.” International Journal of Project Management, 10(4), 196-206. Whittaker, S. and Schwarz, H. (1995). “Back to the Future: Pen and Paper Technology Supports Complex Group Coordination.” Conference on Human Factors in Computing Systems, 495 - 502.Zhang, H. and Tam, C.M. (2003). “Fuzzy decision making for dynamic resource allocation.” Construction management and economics, 21(1), 31-41.