The Logistics Estimation Workbook (LEW) provides an automated sustainment planning tool focused on brigade combat teams. It is designed to improve the logistics estimation process during planning and orders development, and it can be tailored for all phases of an operation.The LEW uses doctrinal profiles and usage rates to calculate supply, maintenance, transportation, and casualty estimates. The planning factors used in the LEW mirror those used by operations logistics planners, by the Combined Arms Support Command's Planning Data Branch, and in the Theater Sustainment Battle Book. Additionally, experiences from multiple support operations officers have been included to keep the planning tool relevant.Since 1998, the support operations community has turned to the LEW for help in planning estimates for logistics requirements at the tactical level. This "home grown" tool was developed by a former instructor for the Support Operations Course at Fort Lee, Virginia.The LEW, a simple Microsoft Excel spreadsheet-based tool, quickly became popular with Combined Logistics Officers Advanced Course students. Over the years, the tool has been added to the programs of instruction for the Logistics Captains Career Course, the Support Operations Course, and other logistics courses.Since its inception 18 years ago, keeping the LEW up-to-date has been the responsibility of the user community. The LEW is a compilation of tools that draws from Army logisticians' experiences. As the user community faces a new challenge and develops a tool or method to address it, the LEW is modified to share the technique. For instance, during a National Training Center deployment, a brigade combat team's S-4 and support operations officer provided the basis of the tentage and latrine worksheet using the Central Command Sand Book as a guide.This was expanded during an Iraq deployment in which concrete, trash, and gray and black water planning capabilities were added. A new G-1/G-4 battle book highlighted the need to capture a units' lift and haul capabilities, so that was added to the LEW as well.Multiple critiques of the shortfalls of automated logistics planning tools in articles and monographs resulted in the addition of truck equivalents and an integrated synchronization matrix. The critical requirement for extending the life of the LEW is that Soldiers continue to share experiences and products.There is always room for improvement. Planning tools, especially ones that are not tied to live data, are not going to address every situation. These tools do not understand cultural nuances or real-world changes. With your insights, they can improve planning by giving you information to combine with your knowledge, your training, and your integrated plan with your maneuver counterparts. ____________________________________________________________________________Lt. Col. Damian A. Green is a G-4 staff officer. He holds a bachelor's degree in education from Providence College and master's degree in supply chain management from the University of Kansas. He is a graduate of the Infantry Officer Basic Course, the Combined Logistics Officers Advanced Course, the Combined Arms and Services Staff School, the Support Operations Course, Intermediate Level Education and the School of Advanced Military Sciences. ______________________________________________________________________________ This article was published in the November-December 2016 issue of Army Sustainment magazine.