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The United States has published historical and current data about the exact size of its nuclear stockpile.[1][2][3] In addition, it discloses detailed information regarding its nuclear-capable delivery vehicles, missile launches, deployment numbers and locations, nuclear doctrine, and modernization plans, among other key elements.[4][5][6][7]
This degree of transparency is primarily due to several factors:
— The United States’ participation in arms control and risk reduction treaties that require and encourage notifications and disclosures (e.g. the now-expired New START bilateral agreement, which limited deployments of strategic warheads and launchers, and the 1988 bilateral agreement on the pre-notification of ballistic missile launches).[8][9]
— The requirement of the US Departments of Defense and Energy to justify funding requests to Congress, which can in turn interrogate and request additional information through updates, testimony, or studies.[10][11][12]
— The robust US civil society and media landscape, including government-funded agencies like the Government Accountability Office and the Congressional Budget Office; investigative journalists; and nongovernmental organizations that report on, request comment from, and critique government programs and plans.[13][14]
— A legacy culture of responsible transparency and open government, supported by legal mechanisms like the Freedom of Information Act, which allow researchers to access certain details about nuclear programs that would otherwise be classified.
— A belief that, as the US National Nuclear Security Administration stated in 2024, 'Increasing the transparency of states’ nuclear stockpiles is important to nonproliferation and disarmament efforts, including commitments under the Nuclear Non-Proliferation Treaty, and efforts to address all types of nuclear weapons, including deployed and non-deployed, and strategic and non-strategic.'[3][16]
However, transparency levels regarding the US nuclear arsenal and related facilities can fluctuate significantly depending on the administration or particular modernization program. For example:
— The United States does not confirm or deny the presence of nuclear weapons at any specific location.
— For many years most details on the budget and characteristics of the upcoming B-21 Raider—the Air Force’s new nuclear-capable stealth bomber—were classified.[17][18]
— Prior to the Obama administration, the United States had never disclosed the size of its nuclear stockpile and its numbers of annually dismantled warheads. Beginning in 2010, the United States did so on a near-annual basis until 2019, when the first Trump administration stopped this practice. The Biden administration restored stockpile transparency in 2021, denied it in 2023, and restored it again in 2024.[19] The denial of declassification requests in 2023 included the justification that 'the Department of Defense and Department of Energy/National Nuclear Security Administration do not believe that [it] is in the best interest of the United States,' but did not provide any additional details.[20]
— The United States has selectively removed or omitted certain sensitive details from official documents after widespread public reporting and critique. For example, in the North Atlantic Treaty Organization’s Security Investment Program budget for Fiscal Year 2023, the US Department of Defense included 'the UK' among a list of countries slated for infrastructure modernization at 'special weapons' storage sites. While the government did not explicitly state that 'special weapons' referred to nuclear weapons, following an influx of scrutiny indicating the potential return of US nuclear weapons to UK soil for the first time in 15 years, the following year’s budget document for the same program did not include any country names.[21][22]
— Following Russia's unilateral suspension of New START in February 2023, the United States disclosed one final set of deployment-related treaty data from March 2023, but has not released any deployment data since then.[8][23]
Until March 2023, the United States disclosed its inventory of intercontinental ballistic missile launchers, submarine-launched ballistic missile launchers, and heavy bombers according to the counting rules of the New START Treaty twice a year.[9] These figures were published in aggregated form on the US Department of State website, and the disaggregated data was available upon request.[1]
However, New START counting rules did not necessarily correspond to the actual numbers of delivery systems, as the United States maintains certain test assets that were not subject to counting under the Treaty, and the Treaty also does not cover nuclear-capable fighter-bomber aircraft like the F-15, F-16, and F-35. In addition, because New START focused on counting warheads and launchers, these figures did not include the total numbers of US delivery systems.
The United States typically discloses how many units of new nuclear-capable delivery systems it intends to purchase. For example, disclosures from the US Air Force related to its incoming B-21 Raider heavy bomber indicate that the US government will purchase a 'minimum of 100 aircraft.'[3][4] US officials also occasionally state the number of delivery vehicles of particular types that are present in the US arsenal. In March 2025, the Commander of US Strategic Command advocated to purchase 145 B-21 bombers instead of 100, which 'gives us 220 bombers when the [B-52s] are included.'[5]
Another disclosure related to the acquisition of a new delivery system was the Milestone B procurement decision for the new Sentinel intercontinental ballistic missile (ICBM), acquired through a Freedom of Information Act request. It noted that the United States planned to purchase 659 units of the Sentinel.[2] It is not common practice for the United States to disclose the number of missiles remaining in its inventory as these units eventually get depleted through regular flight tests and maintenance. However, given that missile tests are publicly announced, it is theoretically possible for analysts to keep track of these numbers.
Budget documents and reports from government agencies like the Government Accountability Office, Congressional Budget Office, and Congressional Research Service, also provide data on nuclear-capable delivery systems.[6][7][8]
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The annual Stockpile Stewardship and Management Plan of the US National Nuclear Security Administration (NNSA) includes a table of all current warheads in the US stockpile and their associated delivery systems, although it is primarily intended to describe plans for warhead modernization, infrastructure recapitalization, and workforce development. The table lists every delivery system capable of carrying each particular warhead; the mission of each warhead, distinguishing between strategic and nonstrategic weapons; and which service (Air Force, Navy, or select NATO forces) is responsible for its deployment.
In the Stockpile Stewardship and Management Plan for Fiscal Year 2025, the United States includes the following categories of nuclear-capable delivery systems: Minuteman III intercontinental ballistic missile(ICBM); Trident II D5 submarine-launched ballistic missile; F-15; F-16; F-35; certified NATO aircraft; B-2 bomber; and B-52 bomber.[1]
Similar information can be found in reports from other sources like the Government Accountability Office (GAO). For example, a 2021 GAO publication included a table of all currently fielded and replacement nuclear triad delivery systems, missiles, and nuclear weapons. It included the same systems as listed in the Stockpile Stewardship and Management Plan, as well as the following replacement delivery systems: Columbia-class ballistic missile submarine, Long Range Standoff missile (LRSO), B-21 bomber, and Ground Based Strategic Deterrent ICBM.[2]
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In 2020, the US Department of Defense published an updated version of its Nuclear Matters Handbook, which gives a comprehensive overview of the US nuclear arsenal. The latest edition includes a detailed examination of the National Nuclear Security Administration’s Nuclear Security Enterprise, spanning eight sites: Los Alamos National Laboratory, Lawrence Livermore National Laboratory, Sandia National Laboratories, Kansas City National Security Campus, the Pantex Plant, the Savannah River Site, the Y-12 National Security Complex, and the Nevada National Security Site.[1]
The Nuclear Matters Handbook also includes details about the 'strategic materials' that are managed at each site, and their relation to the nuclear arsenal: the Los Alamos National Laboratory is currently responsible for managing plutonium pits–the core of a nuclear weapon that initiates the chain reaction required for a nuclear explosion; the Y-12 complex is responsible for managing uranium and lithium; and the Savannah River Site is responsible for managing tritium.
The Handbook also notes plans for the conversion of the Mixed Oxide Fuel Fabrication Facility at the Savannah River Site to a plutonium processing facility that will be capable of producing at least 50 pits per year, and for the recapitalization of a plutonium facility at Los Alamos National Laboratory to produce at least 30 pits per year. It further notes that the US government currently has no capacity to enrich uranium domestically but is developing plans to re-establish that capability.[1]
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The United States displays different levels of transparency regarding its total holdings of fissile materials, depending on the type of material.
In 1998, the International Atomic Energy Agency (IAEA) published Guidelines for the Management of Plutonium (INFCIRC/549), for which the five countries defined as ‘nuclear weapon states’ in the Nuclear Non-Proliferation Treaty (NPT) agreed to publish annual statements of their holdings of civil plutonium. While INFCIRC/549 covers most categories of plutonium, certain categories—such as plutonium with an isotopic concentration of plutonium-238 exceeding 80 percent, plutonium on which IAEA safeguards have been exempted or terminated, or plutonium used in gram quantities or as a sensing component in instruments—are exempt.[1]
The most recent US declaration, from 2023, noted holdings of less than 0.05 metric tons of unirradiated separated plutonium produced during the course of manufacture or fabrication, 4.6 metric tons of plutonium contained in unirradiated MOX fuel, and 44.6 metric tons of unirradiated separated plutonium held elsewhere—all of which were roughly the same as the previous year’s figures.[2]
INFCIRC/549 does not cover holdings of low-enriched or highly-enriched uranium (HEU), and the United States does not regularly provide any public information on these stocks. The most recent US disclosure regarding its HEU stocks was in a 2016 Fact Sheet published by the White House, which included data from between 1996 and 2013.[3] The Fact Sheet noted that as of September 30, 2013, the total US inventory of HEU was 585.6 metric tons, of which 499.4 metric tons was for 'national security or non-national security programs including naval propulsion, nuclear energy, and science.'
The Fact Sheet also noted that 'of the remaining 86.2 metric tons, 41.6 metric tons was available for potential down-blend to low enriched uranium or, if not possible, disposal as low-level waste, and 44.6 metric tons was in spent reactor fuel.'[3]
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The US Nuclear Posture Review (NPR), generally issued by each presidential administration, describes US nuclear policy, posture, and force structure, and their interaction with emerging technologies like AI. The most recent iteration of the NPR, published in 2022, states that '[i]n all cases, the United States will maintain a human “in the loop” for all actions critical to informing and executing decisions by the President to initiate and terminate nuclear weapon employment.'[1]
The Commander of US Strategic Command testified to Congress in March 2025 that 'AI will remain subordinate to the authority and accountability vested in humans,' although he did note that the service will use artificial intelligence and machine learning capabilities 'to enable and accelerate human decision-making.'[2] The ultimate decision to use nuclear weapons, however, is one of the few remaining areas relating to US nuclear arsenal where AI does not play an active role.
The Department of Energy’s 'Artificial Intelligence Strategy,' published in October 2025, and the National Nuclear Security Administration’s 'Artificial Intelligence for Nuclear Deterrence Strategy,' published in 2023, both provide details as to how AI is being integrated into the nuclear mission. Of particular note is that AI is increasingly being used to support the stockpile stewardship mission by enhancing US modelling and simulation capabilities, by accelerating and automating the manufacture of systems needed for nuclear deterrence, and by assisting with the maintenance of nuclear weapon systems as they age.[3][4]
The United States does not disclose the ways in which AI is being integrated into its infrastructure for early warning and nuclear command, control, and communications (NC3), but public statements from officials involved in the NC3 modernization process indicate that such integrations are occurring.[2][5]
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The United States generally discloses detailed plans for the modernization of each element of its nuclear arsenal, including warheads, delivery systems, nuclear warhead production, nuclear command and control, and the facilities, networks, and workforce that underpin them.
This degree of transparency can primarily be attributed to the fact that while presidential administrations can issue decisions and guidance about alterations to US nuclear forces, those alterations must be authorized and funds must be appropriated by Congress in order to execute them. As a result, presidential administrations must justify their proposals to Congress through detailed budgetary submissions, congressional testimony, and studies, and in compliance with laws that require certain types of disclosures.
By combining all of these various sources, it is possible to obtain a comprehensive picture of nearly every aspect of the US nuclear modernization program, with the exception of certain details or studies that remain classified (e.g. the Analysis of Alternatives report for the modernization of the intercontinental ballistic missile force, which would provide critical insight into the Department of Defense’s initial justifications for the program).
For example, the updated Nuclear Matters Handbook published by the Department of Defense in 2020 provides details on each warhead, delivery system, scientific and technical facility, and elements of nuclear command, control, and communications infrastructure that are currently being upgraded or modernized.[1]
In addition, the Department of Energy’s annual Stockpile Stewardship and Management Plan provides comprehensive details on each element of the nuclear security enterprise, including budgetary information and upgrades to individual warheads and facilities.[2] Detailed annual budgetary information is disclosed through presidential and service budget requests, which Congress then interrogates, authorizes, and appropriates.[3][4][5]
Despite a degree of classification for some aspects of nuclear modernization and the justifications for it, many documents are ultimately accessible via requests under the Freedom of Information Act.[6]
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In 1994, at the Preparatory Committee for the 1995 Review and Extension Conference of the Nuclear Non-Proliferation Treaty (NPT), states engaged in a discussion relating to negative security assurances. In the context of that discussion, the United States emphasized that negative security assurances did not need to be unconditional, and that they would be given only to states that had renounced nuclear weapons development.[1]
In addition, since 1994, each successive US presidential administration has issued a Nuclear Posture Review (NPR), which describes US nuclear strategy, policy, posture, and forces. The most recent iteration of the NPR, issued in 2022, reaffirmed the longstanding policy with regard to negative security assurances (NSA) that 'the United States will not use or threaten to use nuclear weapons against non-nuclear weapon states that are party to the NPT and in compliance with their nuclear non-proliferation obligations.'[2]
In June 2025, the International Atomic Energy Agency (IAEA) issued a resolution finding that Iran was no longer in compliance with its NPT obligations.[4] As such, while the conditions that apply in relation to the United States’ NSA do not specifically refer to Iran, it is the country that most obviously breaches them. Moreover, the 2022 NPR states that 'U.S. policy is to prevent Iran from acquiring a nuclear weapon,'[2] and the most recent iteration of the US Nuclear Employment Strategy, issued in 2024, affirms that the United States 'is prepared to use all elements of national power to ensure that outcome.'[3]
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Since 1994, each successive US presidential administration has issued a Nuclear Posture Review (NPR), which describes US nuclear strategy, policy, posture, and forces. The most recent iteration of the NPR, issued in 2022, reaffirmed longstanding policy that the United States 'maintains a very high bar for nuclear employment,' and 'would only consider the use of nuclear weapons in extreme circumstances to defend the vital interests of the United States or its Allies and partners.'[1] However, the United States has traditionally not provided any specific details as to what constitute 'vital interests.'
This guidance was translated into the most recent iteration of the Nuclear Employment Strategy, which was issued in November 2024 and repeats the above lines verbatim.[2]
In addition, US nuclear declaratory policy leaves open the possibility of nuclear first-use, as the most recent NPR indicated that the adoption of a no-first-use policy 'would result in an unacceptable level of risk in light of the range of non-nuclear capabilities being developed and fielded by competitors that could inflict strategic-level damage to the United States and its Allies and partners.'[1] The 2024 Nuclear Employment Strategy elaborates on this further, noting that the United States 'does not depend on a launch-under-attack policy to ensure a credible response.'[2]
In a shift from previous guidance, the 2022 guidance requires the Department of Defense to 'assess the ability of non-nuclear capabilities to contribute to deterrence, and [...] integrate these capabilities into operational plans, as appropriate.' This is being done 'to advance the goal of reducing reliance on nuclear weapons…'[1]
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The United States issues advance notice of long-range missile tests, space launch activities that might be mistaken for nuclear missile launches, and military exercises involving nuclear and dual-capable weapon systems, through three main avenues:
1. Pursuant to a 1988 bilateral US-Russia(USSR) treaty, the United States issues notifications of test launches of intercontinental ballistic missiles and submarine-launched ballistic missiles. These notifications include the area from which the launch will take place and the geographic coordinates of the planned impact area(s) of the reentry vehicle(s), and must be issued no less than 24 hours in advance of launch. These notifications, the details of which are not publicly disclosed, are issued through the National Nuclear Risk Reduction Centers of the two countries and do not cover shorter-range missile launches.[1]
2. The United States regularly issues press releases in advance of its long-range missile test launches and nuclear weapons exercises, as these are typically planned months or years in advance and correspond to a rigorous testing schedule. For example, on November 3rd, 2025, Vandenberg Space Force Base issued a press release stating that 'An operational test launch of an Air Force Global Strike Command unarmed Minuteman III intercontinental ballistic missile is scheduled between 11:01 p.m. to 5:01 a.m. Pacific Time, Nov. 4, from north Vandenberg.'[2]
3. The United States issues regular navigational warnings to airmen and mariners for each missile and rocket test that it conducts, pursuant to the Convention on International Civil Aviation and in support of the Global Maritime Distress and Safety System. These notifications provide specific information about the nature of the launch, the coordinates of the launch and impact areas, and the dates under which the warning remains in effect. However, these warnings do not indicate what type of missile is being launched.[3]
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Since 1994, each US presidential administration has issued a Nuclear Posture Review (NPR), which describes US nuclear strategy, policy, posture, and forces. The policies articulated in the most recent NPR, published in 2022, were translated into an updated version of the US Nuclear Employment Strategy published in 2024. The guidance in both documents noted explicitly that the role of US nuclear weapons includes deterring ‘strategic attacks’.
The 2022 NPR did not define ‘strategic attack’, but stated, ‘Consistent with prior reviews, our nuclear strategy accounts for existing and emerging non-nuclear threats with potential strategic effect for which nuclear weapons are necessary to deter.'[1] However, the 2018 NPR had described strategic non-nuclear attacks as follows: ‘Significant non-nuclear strategic attacks include, but are not limited to, attacks on the U.S., allied, or partner civilian population or infrastructure, and attacks on U.S. or allied nuclear forces, their command and control, or warning and attack assessment capabilities.'[3] The 2018 NPR also listed 'chemical, biological, cyber, and large-scale conventional aggression' as examples of 'non-nuclear strategic threats.'[3]
The 2024 Nuclear Employment Strategy affirmed that ‘The roles of nuclear weapons in United States strategy are to deter strategic attack, assure allies and partners, and enable achievement of national objectives in extreme circumstances if deterrence fails…’ and defined a strategic attack as ‘a nuclear attack of any scale as well as a significant, high-consequence, non-nuclear attack that has strategic-level effect.’[2]
It is important to note that these documents do not state that the United States necessarily would use nuclear weapons in response to these types of attacks, but rather that it might do so.
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The United States periodically discloses figures for its current nuclear stockpile, annually dismantled warheads, and retired warheads awaiting dismantlement.
It did this for the first time in 2010, when it declassified the entire history of the US nuclear stockpile, including the annual stockpile size, the number of dismantled warheads since 1994, and the number of retired warheads awaiting dismantlement.[4]
The United States continued to disclose this data on an annual basis until 2019, when the US Department of Defense denied successive declassification requests.[5] In 2021, transparency was restored and the figures from the missing years were disclosed.[6] Another disclosure of these figures was made in 2024, similarly restoring the missing data from the previous years.[1] It appears the United States is shifting towards disclosing these figures on an ad hoc, rather than a scheduled basis.
In addition, as a party to the now-expired New START agreement between Russia and the United States, which limited numbers of deployed strategic warheads and launchers,[7] the United States previously released its aggregate numbers of strategic warheads on deployed intercontinental ballistic missiles, submarine-launched ballistic missiles, and nuclear warheads on deployed heavy bombers (each bomber counted as one warhead under the Treaty’s counting rules). This release occurred twice a year throughout most of the duration of the treaty.[2]
Although the United States did not publish the New START data in disaggregated format, this data was available upon request from the Department of State throughout this time. Following Russia's unilateral suspension of New START in February 2023, the United States disclosed one final set of deployment-related treaty data from March 2023.[3] It has not released any deployment data since then.
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The United States does not disclose the exact yields of the warheads in its current arsenal. However, it does occasionally disclose information about current warheads that would help analysts make educated assumptions about their yields, by disclosing information about warhead designs or yields relative to other weapons. For example, in its announcement on the development of the new B61-13 gravity bomb, the Department of Defense stated that the weapon would 'have a yield similar to the B61-7, which is higher than that of the B61-12.'[1]
The United States has also declassified the exact yields of many of its nuclear tests, as well as the yields of some nuclear weapons that are no longer in the US arsenal.[2][3][4] For example, the yield of the B53—once the highest-yield nuclear weapon in the US arsenal—was officially declassified in 2014 and revealed to be 9 megatons, although it had already been retired and dismantled by that time.[5]
In addition, the United States has declassified the total annual megatonnage of explosive force in its arsenal between 1945 (0.04 megatons) and 1994 (2,375.3 megatons); the year of the largest stockpile megatonnage was 1960 (20,491.17 megatons).[6] While this dataset was not disaggregated by weapon, it can be used to make analytical estimates for individual warheads.
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