Research and analysis

Background quality report: international defence statistics 2025

Published 4 December 2025

1. Contact Details

The Analysis Directorate welcomes feedback on our statistical products. If you have any comments or questions about this publication, or about our statistics in general, you can contact us as follows:

Analysis-Expenditure Head of Branch

Telephone: 0303 378 6554

Email: Analysis-Expenditure-PQ-FOI@mod.gov.uk

If you require information which is not available within this or other available publications, you may wish to submit a Request for Information to the Ministry of Defence under the Freedom of Information Act 2000.

Analysis Directorate (Analysis-Expenditure)
Ministry of Defence
Teak, Level 1, Wing 3
MOD Abbey Wood North
Bristol
BS34 8QW

For general MOD enquiries, please call: 020 7218 9000

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2. Introduction and Statistical Presentation

The International Defence Expenditure Bulletin (henceforth in this document ‘International Defence’) is produced annually and contains spending data from the most recent full calendar year for which data are available.

Specifically, this bulletin is published to provide information on defence expenditure of NATO member states with a focus on expenditure as a percentage of their Gross Domestic Product (GDP) and the share of defence expenditure spent on equipment . A comparison of two international defence spending data sources, the Stockholm International Peace Research Institute (SIPRI) and the International Institute for Strategic Studies (IISS), is provided, focusing on top worldwide spenders. Trends for the UK, France, Germany, and the USA are given particular focus.

The bulletin consists of an HTML report which focuses on commentary and data visualisations, and an Open Document Spreadsheet (ODS) which contains the data behind the text and visualisations.

2.1 Publication Frequency

The International Defence bulletin is produced annually and contains figures from the most recent calendar year for which data are available.

2.2 Publication History

The MOD has published international comparison statistics since 2001. Up until 2012, these were published in the UK Defence Statistics (UKDS) Compendium. Since 2013, these statistics have been published as the standalone International Defence Expenditure bulletin.

From 2016, details on NATO countries’ equipment expenditure as a percentage of defence spending has been included in the International Defence bulletin. Figures are presented in Figure 5 and Table 3, and show each NATO country’s percentage in relation to NATO’s 20% minimum target.

In 2019, we omitted the section on ‘Currency Conversion and International Comparisons’ following an internal review of the International Defence bulletin. Due to the nature of the relatively static comparisons of Market Exchange Rates (MER) and Purchasing Power Parity (PPP) rates from year-to-year it was deemed that this would sit more appropriately as a background note in the methodology rather than its own section outright. Comparison data can still be found within Tables 4a and 4b of the supporting data tables.

3. Statistical Processing

3.1 Source Data

This bulletin uses three main data sources in its international comparisons:

• NATO’s Defence Expenditures of NATO Countries.
• SIPRI Military Expenditure Database 1949 to 2024.
• IISS Military Balance 2025.

In addition:

• The International Monetary Fund (IMF) World Economic Outlook Database is updated biannually and provides global macroeconomic data, including population size and Purchasing Power Parity rates for each country.
• The UK Defence Statistics Compendium was produced by the Ministry of Defence up until 2013 as a collection of statistical releases relating to Defence. This publication series included details on international comparisons of defence expenditure up until 2012.

Further details on specific usage are discussed in the following section on Data Compilation.

3.2 Data Compilation

2019 saw the general production process enhanced by using an open-source programming language to automate large parts of the data processing. As well as reducing production time, the quality of the publication was improved, and the process can be easily reproduced. Additional quality assurance measures were programmed into the data pipeline, reducing the scope for human error that was more likely to occur when doing the large volume of manual data manipulation that was previously required. This process has once again been used for 2025’s publication.

Below, the methodology and production for each section of the bulletin and its corresponding table number is described.

NATO Countries’ Defence Expenditure (Tables 1 to 3)

Figures in Table 1 are derived from NATO’s latest published data on Defence Expenditure of NATO Countries (2014 to 2025). Current prices are converted into constant 2024 prices using inferred deflators from the NATO data in current and constant 2021 prices. Currency conversions are actioned using exchange rates inferred from US dollar and local currency totals reported in the same NATO press release.

The data underlying Tables 2 and 3 were obtained from Defence Expenditure of NATO Countries (2014 to 2025).

Top Global Military Spenders (Tables 4a to 4b)

When converting expenditure into a common currency, there are two commonly used methods. The first is to use Market Exchange Rates (MER), meaning the price at which two currencies can be exchanged on foreign exchange markets. The second is to use Purchasing Power Parities (PPP), an index of how much a certain bundle of goods costs in one country relative to another, to carry out the currency conversion.

Table 4a presents international comparisons for the top ten countries in terms of MER. This data was originally published in the SIPRI Military Expenditure Database 1949 to 2024.

SIPRI’s defence expenditure in MER is converted to PPP using Purchasing Power Parity rates published in the International Monetary Fund’s World Economic Outlook. The top ten countries ranked by PPP are presented in Table 4b.

IISS and SIPRI Defence Expenditure (Tables 5a and 5b)

This section presents a comparison of international defence expenditure from two widely used sources to highlight the challenges of varying definitions across organisations. Table 5a presents the defence expenditure for the top 15 countries from the IISS Military Balance 2025. Table 5b shows the equivalent based on SIPRI definitions.

Focus on NATO Allies (Tables 6 and 9)

NATO has collected defence expenditure data on its member states since it was first established in 1949. Tables 6 to 9 use this data to present a long-term focus and comparison of the UK, France, Germany, and the USA since 1980.

Tables 7 and 8 additionally use IMF World Economic Outlook data to allow comparisons of defence spending and military personnel relative to population size.

Where conversion to constant prices is required in Tables 7 and 9, deflators have been inferred from NATO’s original current and constant 2021 prices. Currency conversions have been actioned using exchange rates inferred from US dollar and local currency totals reported in the same NATO press release.

4. Quality Management

4.1 Quality Assurance

While the International Defence bulletin is not an Official Statistic, certain quality management processes are still actioned for assurance:

• Regularly monitoring content via an annual internal assessment.
• Providing a mechanism for reporting and reviewing revisions and corrections.
• Ensuring Background Quality Reports are published alongside reports and are updated regularly.

4.2 Quality Assessment

All underlying data is collected by external organisations. The MOD has no control over the quality, reliability and coverage of data contained within these sources and does not endorse any specific output. Data provided in this publication fall outside the scope of Official Statistics and as such, must be regarded as illustrative only.

5. Relevance

5.1 User Needs

These statistics are often used within the MOD to provide context in papers, press lines and briefings. In 2010 and 2015 they were used to underpin benchmarking work for the UK Strategic Defence and Security Review (as well as for the Australian SDSR) and to inform the corresponding Spending Review settlements. The production of the tables has placed the Analysis-Expenditure branch (the producers of this Bulletin within MOD) in a position to offer guidance on the use of these statistics to others within the Department and they have formed the basis of several international collaboration projects; this is a strength of the International Defence Bulletin.

Externally to the MOD, policy think tanks such as the Royal United Services Institute (RUSI) and International Institute for Strategic Studies (IISS) have used the data for policy papers and think pieces. Occasionally contextual questions from academics and interested parties are received.

There have been some internal requests for performance metrics measuring international defence capabilities. There is consistent interest in making international comparisons based on defence ‘outputs’ rather than ‘input’ measures, and these statistics provide information solely about the latter of these. The lack of ‘output’ measures could be considered a weakness of this Bulletin.

We continually monitor the requests for information that we receive and identify any common themes in these requests. The MOD invites users to provide further feedback to the statistical output teams on any of their publications or reports using the contact information contained within each publication.

6. Accuracy and Reliability

There are a number of issues surrounding the accuracy of NATO, SIPRI, and IISS data which include compliance with definitions, different treatment of pension contributions and tax regimes, and conversion methods. This is explained further in this document under the Coherence and Comparability section. In addition, as some countries do not provide returns to SIPRI or IISS, some of their figures are estimates. MOD has no control over the quality, reliability and coverage of the data contained in tables sourced from these organisations.

Whilst NATO data is available for 2025, these are estimates only. As such, this bulletin uses data up until 2024 which is also consistent with time periods contained in the latest available data from IISS and SIPRI.

6.1 Data Revisions

Corrections to the International Defence bulletin are signposted online and accompanied by notes to the tables and in the bulletin where appropriate. We will follow the Ministry of Defence Revisions Policy while making any corrections.

7. Timeliness and Punctuality

7.1 Timeliness

This publication has a targeted release date of late summer each year. However, the timeliness of the bulletin ultimately depends on the availability of source data from NATO, SIPRI and IISS.

7.2 Punctuality

The International Defence bulletin is not an Official Statistic so does not appear on MOD’s Calendar of Upcoming Releases.

8. Coherence and Comparability

The statistics in this bulletin are consistent with those published by NATO, SIPRI and IISS. Where MOD has converted data into US dollars or to constant prices, this methodology has been agreed with NATO statistical experts.

NATO, SIPRI and IISS have different definitions of military expenditure which, additionally, differ from the definition of Defence Expenditure used to compile the MOD’s own accounts presented in the Departmental Resources bulletin. It is therefore not possible to easily compare spending figures from these different sources.

When undertaking international comparisons of defence it is important to consider some well documented issues relating to the comparability and granularity of the international source data. Making direct comparisons will never be straightforward because:

• Whilst there are standardised definitions of defence spending and accounting conventions used by international organisations, principally the UN and NATO, not all countries record and publish their defence spending in accordance with such definitions and conventions. The standards themselves are not always transparent, adding to the difficulties of comparing estimates produced by different organisations. More information relating to the revised NATO definition can be found on the NATO website. Expenditure is included for countries that provide Military Assistance; expenditure is not included for countries receiving assistance. More information relating to the SIPRI definition of military expenditure can be found on the SIPRI website.
• Some countries’ actual defence expenditure may be very different from their budgeted expenditure.
• Differences in national tax regimes and the treatment of pension contributions can lead to significant distortions in expenditure.
• Departments other than defence departments may be deemed to contribute to defence whilst some spending by defence departments can be categorised as supporting other activities.
• The choice of conversion method (for example, Market Exchange Rates (MER) or Purchasing Power Parity (PPP) rates) used to convert to a common currency can result in significantly different rankings of global defence spending. Using MER for instance tends to undervalue the currency, and hence the scale of expenditure, for countries with lower national incomes. Attempts are often made to circumvent this problem using PPP rates. These use currency conversion rates which equalise the overall price of a bundle of goods and services in each country. However PPP rates can be highly inaccurate because of the difficulty of allowing for differences in quality and devising appropriate and relevant “weightings” of individual goods and services. Civilian based PPPs may also not be representative of defence goods and services. Further information on the measurement and uses of PPP rates can be found in the Organisation for Economic Co-operation and Development’s Statistics Brief.

9. Accessibility and Clarity

The statistical bulletin can be accessed on the GOV.UK website where it is available to download in HTML format. Its release is noted in the ‘Finance and Economics’ section of MOD’s list of Accredited Official and Official Statistics by topic and can also be found by using an internet search engine.

All tables and data behind any graph or chart in the report are available as an accessible Open Document Spreadsheet (ODS).

Visualisations have been chosen to best display patterns and trends within the data. Terms used in the commentary are defined within the glossary of the HTML bulletin.

Figures within the bulletin and ODS tables are often rounded to aid with clarity. In these instances, we have followed the Ministry of Defence Rounding Policy.

Should you have any feedback on the accessibility of any part of the bulletin or accompanying data tables then the Analysis Directorate encourages you to get in touch via any of the means noted in the Contact Details section.

10. Trade-offs between Output Quality Components

There is occasionally a trade-off between timeliness and comparability; the timing of the publication of these statistics ultimately depends on when the source material is released.

11. Cost and Respondent Burden

The underlying source data is already collected by external organisations. Production of the International Defence bulletin therefore has minimal burden on respondents as it is limited to analysis and presentation rather than data collection.

12. Confidentiality and Security

12.1 Confidentiality - Policy

In producing these statistics, we adhere to the MOD Analysis Directorate Confidentiality Policy.

12.2 Confidentiality - Data Treatment

The Analysis Directorate maintains good links with policy colleagues to ensure that these statistics are understood and to prevent misuse. We regularly review our commentary and visualisations to ensure the data is presented in the best way possible.

12.3 Security

The team operate a secure environment for the storage of data. All data used in this bulletin is stored and managed securely on an internal SQL server.