The independent resource on global security

Sources and methods

    1.  Explanation of the Transfer Registers

    2.  Explanation of the TIV tables

     3.  Coverage

     4.  Sources

     5.  Conventions, abbreviations and acronyms 

1. Explanation of the Transfer Registers

Transfer Registers are outputs that contain information on deals between specific arms suppliers and recipients over a specific time period that are included in the SIPRI Arms Transfers Database.  A deal is only included in a Transfer Register if reliable information has been verified that an order has been placed or deliveries have begun.

You can also choose whether to include all deals or only those involving certain types of weapon system, and whether the Transfer Register is laid out according to supplier(s) or recipient(s).

For all deals, the following information is provided:

  • Number ordered—the number of items ordered under the deal
  • Weapon designation—the designation of the weapon system concerned
  • Weapon descriptiondescription of the weapon system concerned
  • Year of order/licence—the year the order was placed or, in the case of licensed production, the licence was issued
  • Year(s) of deliveries—the year or years during which deliveries took place. If no deliveries have yet been made, this field is left blank.
  • Number delivered/produced—the number of items delivered or produced under the deal
  • Comments—any additional information that is known about the deal. This can include the financial value of the deal, what the weapons will ostensibly be used for, whether the weapons are being donated as military aid, and any information on offsets linked to the deal.

Information concerning the year of order, year(s) of deliveries and number delivered/produced figures are in brackets if the accuracy of the data is uncertain.

In cases where a delivery has been identified but either the supplier or the recipient cannot be identified with certainty, transfers are registered as coming from ‘unknown’ suppliers or going to ‘unknown’ recipients. Where a deal involves weapon systems that are to be produced by two or more countries in cooperation, and if it is not clear which country will make the final delivery, the supplier is listed as ‘multiple’. Where possible, the comment field in the registers will identify the most likely suppliers or recipients.


2. Explanation of the TIV tables

SIPRI statistical data on arms transfers relates to actual deliveries of major conventional weapons. To permit comparison between the data on such deliveries of different weapons and to identify general trends, SIPRI has developed a unique system to measure the volume of international transfers of major conventional weapons using a common unit, the trend-indicator value (TIV).

The TIV is based on the known unit production costs of a core set of weapons and is intended to represent the transfer of military resources rather than the financial value of the transfer. Weapons for which a production cost is not known are compared with core weapons based on: size and performance characteristics (weight, speed, range and payload); type of electronics, loading or unloading arrangements, engine, tracks or wheels, armament and materials; and the year in which the weapon was produced. A weapon that has been in service in another armed force is given a value 40 per cent of that of a new weapon. A used weapon that has been significantly refurbished or modified by the supplier before delivery is given a value of 66 per cent of that of a new weapon.

SIPRI calculates the volume of transfers to, from and between all parties using the TIV and the number of weapon systems or subsystems delivered in a given year. This data is intended to provide a common unit to allow the measurement of trends in the flow of arms to particular countries and regions over time. Therefore, the main priority is to ensure that the TIV system remains consistent over time, and that any changes introduced are backdated.

In cases where deliveries are identified but it is not possible to identify either the supplier or the recipient with an acceptable degree of certainty, transfers are registered as coming from 'unknown' suppliers or going to 'unknown' recipients. In cases where there is an arms transfer agreement for weapons that are produced by two or more cooperating countries, and if it is not clear which country will make the final delivery, the supplier is listed as 'multiple'.

SIPRI TIV figures do not represent sales prices for arms transfers. They should therefore not be directly compared with gross domestic product (GDP), military expenditure, sales values or the financial value of export licences in an attempt to measure the economic burden of arms imports or the economic benefits of exports. They are best used as the raw data for calculating trends in international arms transfers over periods of time, global percentages for suppliers and recipients, and percentages for the volume of transfers to or from particular states.

Examples of SIPRI TIV

To illustrate how the SIPRI TIV is constructed/calculated, four types of transfer are outlined below using actual SIPRI TIV and deliveries: a transfer of a newly produced complete arms; a transfer of second-hand arms ; a transfer of significant components for major arms; and a licensed production arrangement for major arms. All of the examples are for items delivered in 2021.

  • The transfer transfer of newly produced complete weapons systems: In 2021, France delivered 6 Rafale FGA aircraft to Qatar. One Rafale is valued at 55 million SIPRI TIV. Therefore, the delivery is valued at 330 million (6 x 55) SIPRI TIV.
  • Transfer of second-hand weapons: In 2021, Italy delivered 50 second-hand Centauro AFSV to Jordan. One new Centauro is valued at 2.25 million SIPRI TIV and a used example is valued at 0.9 million SIPRI TIV (40 per cent of the value of a new example). Therefore, the delivery is valued at 45 million (50 x 0.9) SIPRI TIV.
  • Transfer of significant components for major conventional weapons systems: In 2021, Russia delivered 200 D-30 turbofan engines to China for use in H-6K combat aircraft tanks and Y-20 transport aircraft designed and produced in China. One D-30 is valued at 3 million SIPRI TIV. Therefore, the delivery is valued 600 million (200 x 3) SIPRI TIV.
  • Licensed production arrangement: In 2021, Italy received 2 F-35A FGA aircraft produced in Italy under license from a US company. One F-35A Lightning-2 is valued at 55 million SIPRI TIV. Therefore, the delivery is valued at 110 million (2 x 55) SIPRI TIV.



3. Coverage

Types of weapons

Since publicly available information is inadequate for the tracking of all weapons and other military equipment, SIPRI covers only what it terms major weapons. These are defined by SIPRI as the following:

  • Aircraft: all fixed-wing aircraft and helicopters, including unmanned aircraft (UAV/UCAV) with a minimum loaded weight of 20 kg. Exceptions are microlight aircraft, powered and unpowered gliders and target drones.
  • Air defence systems: (a) all land-based surface-to-air missile (SAM) systems, and (b) all anti-aircraft guns with a calibre of more than 40 mm or with multiple barrels with a combined caliber of at least 70 mm. This includes self-propelled systems on armoured or unarmoured chassis.
  • Anti-submarine warfare weapons: rocket launchers, multiple rocket launchers and mortars for use against submarines, with a calibre equal to or above 100 mm.
  • Armoured vehicles: all vehicles with integral armour protection, including all types of tank, tank destroyer, armoured car, armoured personnel carrier, armoured support vehicle and infantry fighting vehicle. Vehicles with very light armour protection (such as trucks with an integral but lightly armoured cabin) are excluded.
  • Artillery: naval, fixed, self-propelled and towed guns, howitzers, multiple rocket launchers and mortars, with a calibre equal to or above 100 mm.
  • Engines: (a) engines for military aircraft, for example, combat-capable aircraft, larger military transport and support aircraft, including large helicopters; (b) engines for combat ships -  fast attack craft, corvettes, frigates, destroyers, cruisers, aircraft carriers and submarines; (c) engines for most armoured vehicles - generally engines of more than 200 horsepower output*.
  • Missiles: (a) all powered, guided missiles and torpedoes, and (b) all unpowered but guided bombs and shells. This includes man-portable air defence systems (MANPADS) and portable guided anti-tank missiles. Unguided rockets, free-fall aerial munitions, anti-submarine rockets and target drones are excluded.
  • Sensors: (a) all land-, aircraft- and ship-based active (radar) and passive (e.g. electro-optical) surveillance systems with a range of at least 25 kilometres, with the exception of navigation and weather radars, (b) all fire-control radars, with the exception of range-only radars, and (c) anti-submarine warfare and anti-ship sonar systems for ships and helicopters*.
  • Satellites: Reconnaissance satellites.
  • Ships: (a) all ships with a standard tonnage of 100 tonnes or more, and (b) all ships armed with artillery of 100-mm calibre or more, torpedoes or guided missiles, and (c) all ships below 100 tonnes where the maximum speed (in kmh) multiplied with the full tonnage equals 3500 or more. Exceptions are most survey ships, tugs and some transport ships.
  • Other: (a) all turrets for armoured vehicles fitted with a gun of at least 12.7 mm calibre or with guided anti-tank missiles, (b) all turrets for ships fitted with a gun of at least 57-mm calibre, and (c) all turrets for ships fitted with multiple guns with a combined calibre of at least 57 mm, and (d) air refueling systems as used on tanker aircraft*.

*In cases where the system is fitted on a platform (vehicle, aircraft or ship), the database only includes those systems that come from a different supplier from the supplier of the platform.

The Arms Transfers Database does not cover other military equipment such as small arms and light weapons (SALW) other than portable guided missiles such as man-portable air defence systems (MANPADS) and guided anti-tank missiles. Trucks, artillery under 100-mm calibre, ammunition, support equipment and components (other than those mentioned above), repair and support services or technology transfers are also not included in the database.

Types of transfers

The SIPRI Arms Transfers Database covers all international sales and gifts of weapons, including manufacturing licences. Weapons on loan or lease are included if the loan or lease is for at least three months. To be included in the database, the following conditions must apply:

  • The transfer must be from one country, rebel force or international organization to another country, rebel force or international organization. Weapons supplied to or from a rebel force or international organization are included as deliveries to or from that group, identified under separate 'recipient' or 'supplier' headings.
  • The equipment must be destined for the armed forces, paramilitary forces (including some police forces) or intelligence agencies of another country, a rebel force or international organization.
  • The equipment must have a military purpose. Systems such as VIP (very important person) aircraft used mainly for other government branches but registered with and operated by the armed forces are excluded. Weapons supplied for evaluation purposes are also not included.
  • The equipment must be transferred voluntarily by the supplier. This includes weapons delivered illegally without proper authorization by the government of the supplier or recipient country but excludes captured weapons and weapons obtained from defectors.

In cases where deliveries are identified but where it is not possible to identify either the supplier or the recipient with an acceptable degree of certainty, transfers are registered as coming from 'unknown' suppliers or going to 'unknown' recipients.

In cases where there is a transfer agreement for weapons produced by two or more cooperating countries and where it is not clear which country will make the delivery, the supplier is identified as 'multiple'. As soon as actual deliveries have taken place it is generally possible to identify in which of the cooperating countries final assembly has taken place and that country is then registered as supplier.


4. Sources

The Arms Transfers Programme uses a wide variety of sources when collecting information for the database.

The one common criterion is that the sources are open; that is, published and available to the general public. The sources include:

  • Newspapers and other periodicals
  • Monographs and annual reference works
  • Press releases, annual reports and other information published by arms producing companies
  • TV broadcasts
  • Blogs, discussion fora and other Internet publications
  • Defence white papers and similar  policy documents
  • The United Nations Register of Conventional Arms (UN Register)
  • National reports on arms exports and imports
  • Defence budget documents and parliamentary records

The most frequently used sources are commercial periodicals specializing in military issues such as Defense News and Jane's Defence Weekly, newspapers and official governmental publications and the UN Register.


The SIPRI Arms Production Project web page provides links to many arms-producing company web sites. 


Sources often provide only partial information, and substantial disagreement between them is common. Order and delivery dates and the exact numbers (or even types) of weapons ordered and delivered, or the identity of suppliers or recipients, may not always be clear. Exercising judgement and making informed cautious estimates are therefore important elements in compiling the SIPRI Arms Transfers Database. If new information is published about transfers of major arms since 1950 this will be used to update the database.


5. Conventions, abbreviations and acronyms

The information below explains the conventions, abbreviations and acronyms used in the Arms Transfers Database.



. . 

Data not available or not applicable

(  )

Uncertain data or SIPRI estimate


million (1000 000)


billion (1000 000 000)


Abbreviations and acronyms




Anti-aircraft artillery


Anti-aircraft vehicle


Amphibious assault landing ship


Armoured command and reconnaissance vehicle


Armoured engineer vehicle


Air Defence


Airborne early-warning


Airborne early-warning and control


Armoured fire support vehicle


Armoured infantry fighting vehicle


Air-to-Ground Surveillance


Anti-mine vehicle


Armoured patrol vehicle


Armoured personnel carrier


Armoured personnel carrier/command post


Anti-radar missile


Armoured recovery vehicle


Air-to-surface missile


Anti-submarine warfare


African Union


Beyond Visual Range Air-to-Air Missile


Close-in weapon system


Excess Defense Articles


Electronic intelligence

EO Electro-optical


Electronic warfare


Fast attack craft


Fighter/ground attack


Foreign Military Funding


Federal Republic of Germany




German Democratic Republic


Infantry fighting vehicle


Intelligence, Surveillance and Reconnaissance


Internal security vehicle






Mine countermeasures


 Medical evacuation


Maritime patrol


Multiple rocket launcher


Offshore patrol vessel


Surface-to-air missile


Southern Amendment Program


Search and rescue


Ship-to-air missile


Ship-to-ship missile


Ship-to-submarine missile


Signals intelligence


Submarine-launched cruise missile


Self-propelled anti-aircraft gun


Self-propelled gun


Short-range air-to-air-missile


Surface-to-surface missile


Submarine-to-ship missile




Unioa Nacional para a Independencia Total de Angola


Very important person


Vertical launch system