CBO’s Interactive Force Structure Tool

Determine the Costs and Capabilities of Customized Plans for the Military’s Forces

The Congressional Budget Office recently calculated the operating costs for every unit in the U.S. armed forces. Using those values, this interactive tool lets you add or subtract brigades, ships, aircraft squadrons, and other units to see the effects on the Department of Defense’s (DoD’s) total operation and support (O&S) costs and the size of the military.

This tool estimates total O&S military personnel and costs. Those values include direct personnel and costs that are directly associated with a major combat unit, indirect personnel and costs that are associated with units that support the major combat unit, and overhead personnel and costs that are associated with the major combat unit’s share of administrative or overhead activities.

These values account for only the O&S costs of units (not acquisition costs or other costs). Values generated using this tool are illustrative and not official CBO cost estimates (learn more about how they differ); instead, the values are based on DoD’s fiscal year 2019 budget submission, using the same methods as in CBO’s July 2016 report The U.S. Military’s Force Structure: A Primer. (Learn more about CBO’s approach to calculating these costs.)


Frequently Asked Questions

What costs are included in this tool?

CBO’s analysis focuses on operation and support costs, which make up about two-thirds of DoD’s “base” budget—the budget excluding separate appropriations provided to fund ongoing military operations. (The other one-third of that base budget is spent mainly on acquisition of weapon systems and on military construction and family housing.) O&S costs include compensation for military personnel, which is paid from the services’ military personnel accounts. O&S costs also include compensation for most civilian employees, health care costs for military and civilian personnel, and the expenses of running a unit (day-to-day operations, equipment maintenance, training, support contractors, and so on), all of which are paid from the services’ or defensewide operation and maintenance (O&M) accounts. O&S costs are very closely related to the size of units—for instance, a unit with 10,000 military personnel will have military personnel costs commensurate with that size—and DoD has a limited ability to change those costs, particularly in the near term.

A spreadsheet providing CBO’s personnel numbers and costs for each type of major combat unit in the military’s force structure, updated to reflect DoD’s 2019 budget submission, can be found at www.cbo.gov/publication/54136.

What costs are not included in this tool?

CBO’s analysis includes O&S costs for major combat units. It does not include acquisition costs (for the development and purchase of major weapon systems, as well as upgrades to existing systems) or construction costs (for infrastructure, such as buildings and housing at military installations). Those costs are significant, together making up almost one-third of DoD’s total base budget (excluding appropriations to fund ongoing military operations).

Why can’t I increase or decrease some elements of the force?

In many cases, CBO judged that it would be unrealistic to allow the force to vary beyond certain parameters within the next five to 10 years. For example, some models of aircraft, such as B-52s, have no active production lines (thus, it would be extremely difficult to procure additional B-52s). In other cases, for ships such as aircraft carriers, it is unlikely that industry could provide an additional carrier in the relevant time frame, because of constraints on the industrial base or because of the time required to construct and commission such ships (nine years in the case of an aircraft carrier). In other cases, CBO judged it highly unlikely that the United States would choose to retire new fleets of aircraft (such as the F-35) currently in production rather than retire older fleets (such as the F-16) that are being replaced by those new aircraft.

Why does this tool show fractional squadrons of aircraft?

In the Air Force and Navy, squadron sizes vary greatly even within a single type of aircraft, making counts of those squadrons an unreliable measure of force structure. To compare costs and personnel across squadrons, CBO translated all Navy and Air Force aircraft squadrons into notional 12-aircraft squadrons for this analysis. That approach can result in fractional squadrons displayed—for example, the Air Force’s 2 squadrons of 8 B-2 bombers each (that is, 16 aircraft) become 1 and 1/3rd of a squadron (that is, one “notional” squadron of 12 aircraft with an additional 4 aircraft).

How does a formal CBO cost estimate differ from the costs shown here?

The average annual costs that CBO uses for this tool, which focus on a five-year period and are subject to numerous simplifying assumptions, reflect a more abstract approach than the one CBO uses to estimate the costs of legislation. That simplified approach allows CBO to make comparisons across all elements of force structure.

CBO’s cost estimates for legislation assist the Congress in enforcing budget rules and limitations and inform the appropriation process. Official cost estimates are highly specific to the exact provisions of a proposed bill, and legislation may encompass a wide variety of provisions. The Congress could direct DoD to alter its force structure in many ways, and CBO would have to see the specifics of a particular piece of legislation before it could produce an official cost estimate. To generate illustrative average annual costs (as this tool does) without specific bill language, CBO’s estimates employ some assumptions about the ways in which the Congress might do so.

Consider a hypothetical authorization bill that would forbid DoD from retiring a class of ships or a type of aircraft—an approach analogous to using this tool to increase the size of the A-10 force. (The increase in the size of the A-10 force this tool allows is to reflect the possibility of retaining existing A-10 aircraft by not retiring them rather than producing new A-10 aircraft.) For the purposes of this tool, CBO has assumed that any such directive would come with a change in the total number of military personnel that the Air Force maintains (the end-strength authorization) and a corresponding change in the military personnel appropriations necessary to support it. In an official cost estimate, however, CBO would include the military personnel appropriations necessary to support whatever end strength the overall authorization bill specified.

Similarly, consider a hypothetical authorization bill that would expand DoD’s purchases of a type of aircraft to equip Air National Guard units. For the purposes of this tool, CBO has assumed that any change in force structure would be implemented so as to preserve the current balance of units between active and reserve components. In an official cost estimate, however, CBO would include only the appropriate costs to provision Air National Guard units as specified by the bill.

One simplifying assumption incorporated in this tool is that the average annual costs it shows do not represent the costs of a particular change in any specific year. (That approach differs from the one used in cost estimates.) Thus, the tool does not show how costs would change over time in accounts that tend to grow even when forces do not change (as happens, for example, as a result of pay raises for military personnel) or how costs would change as a modification to the force structure was implemented (instead, the tool simply presents the costs of a decision as if it had been fully implemented). Because they reflect averages for DoD’s units over the five years in DoD’s budget plans, the costs shown in the interactive tool are “generic” annual costs that should approximate, but not equal, the costs of specific units in specific years.

What if I have other questions, comments, or issues?

Please contact communications@cbo.gov. CBO would welcome any feedback you may have about this interactive tool.

About This Interactive Tool

Casey Labrack and Adam Talaber developed this interactive tool with guidance from David Mosher. Several people within and outside CBO viewed earlier versions of it and provided helpful comments. Bernard Kempinski (formerly of CBO) created the unit graphics. Mark Hadley and Jeffrey Kling reviewed it, Christine Bogusz edited it, Rob Dean (formerly of CBO) integrated the tool into the website, and the Communications team prepared it for release.

This page was last updated on August 15, 2018; the underlying data are based on DoD’s fiscal year 2019 budget submission.