Abstract : DOD and the military services estimate total funding needs for fuel in annual budget requests by using planned consumption (measured in barrels of fuel) and a standard price per barrel set by DOD. Senate Report 114-49, accompanying a bill for the National Defense Authorization Act for fiscal year 2016, included a provision for GAO to review DODs approach to estimating fuel consumption. Among other objectives, this report (1) describes the military services reported actual spending on fuel consumption compared to their budget estimates since 2012, and factors that were reported to have contributed to any differences, and (2) assesses the steps DOD takes to report accurate and complete fuel consumption data in annual budget requests. GAO analyzed DOD budget documents, including military service and DLA fuel data for fiscal years 2012 through 2015 and interviewed DOD officials responsible for preparing fuel consumption budget materials. GAO recommends that DOD (1) develop an approach to reconcile the military services and DLA fuel consumption data and (2) report more complete fuel consumption data to Congress. DOD concurred with the first recommendation and did not concur with the second recommendation, stating that providing additional fuel consumption information could be useful, but doing so would be difficult and labor intensive. GAO believes the recommendation remains valid to ensure that Congress has information to assess trends in fuel consumption, as discussed in the report.