Tank classification Tank classification is a taxonomy of identifying either the intended role or weight class of tank s . The classification by role was used primarily during the developmental stage of the national armoured forces , and referred to the doctrinal and force structure utility of the tanks based on design emphasis . The weight classification is used in the same way truck classification is used , and is intended to accommodate logistic requirements of the tanks Modern tank designs have favoured a " universal " design that has generally eliminated these sorts of classifications from modern terminology , which tends to refer to almost all designs as main battle tanks despite sometimes significant weight differences . A common division in the definition of roles has been between tanks intended to focus on supporting infantry in the assault , and tanks intended for classic cavalry missions of exploitation , screening and reconnaissance . The British referred to these as infantry tank s and cruiser tank s respectively . Other specialist roles include anti - tank vehicle s or tank destroyer s which are generally lightly armoured compared to similar generation multi - purpose tanks , and assault gun s that mount oversized and typically low - velocity guns , for attacking fortifications . Weight - based classifications are useful , but only in reference to a period ' s other tanks . For example , late - World War II medium tanks were as heavy as early - war heavy tanks . Light , medium , and heavy have other meanings than just weight , e . g . , relating to gun size , the amount of armour , and , most importantly , tactical role . For example , in the mid - 1930s to early ' 40s , Nazi Germany developed a new generation of tanks after its Panzer I . It resulted in : the ' medium ' Panzer III , armed with an anti - tank gun and intended to fulfill the general - purpose medium tank role ; and the ' heavy ' , support Panzer IV , initially armed with a 75mm short - barreled gun for engaging bunkers , towed antitank guns and other soft targets , with strong frontal armour but weaker side and rear armour . The differentiation was not absolute : the IV could fire HEAT shells and the III could fire high - explosive shells to attack infantry , but neither was as effective in the roles of the other . As the war progressed , tanks , heavier anti - tank guns , and tank - versus - tank combat became much more common on the battlefield . In order to survive , all tanks required an increase in armour protection and larger guns in order to defeat a similar " up - armouring " taking place on the enemy ' s own designs . The separation of " infantry " and " cruiser " roles generally disappeared and the " universal tank " started to take over . These were generally classified by weight in comparison to tanks from their own country ; for instance , the US fielded the M26 Pershing " heavy " tank , which was heavier than the M4 Sherman . However , the Pershing was very comparable to the German Panther tank which Germany considered a medium , due to the presence of its much larger Tiger II . Overview . Many classification systems have been used over the nearly one hundred years of their history . Classification has always been determined by the prevailing theories of armoured warfare , which have been altered in turn by rapid advances in technology . No one classification system works across all periods or all nations . Tanks are often referred to by weight - based or role - based classification , such as ' light ' , ' medium ' or ' heavy ' . Many types are also described by their tactical role , which depends on contemporary military doctrine . For instance , ' infantry ' and ' cruiser ' tanks are British classifications of the 1930s and ' 40s ; ' infantry ' , ' fast ' , and ' breakthrough ' are contemporaneous Soviet types . Furthermore , expected weights for a given tank type vary over time ; a medium tank of 1939 could weigh less than a light tank of 1945 . Some examples : British and Soviet tacticians up to the time of the Second World War classified tanks into three major roles : infantry , light , and cavalry . Infantry tanks supported infantry units , to integrally support dismounted infantry actions . Light tanks performed the traditional cavalry role of scouting and screening . Cavalry or " cruiser " tank units were meant to exploit breakthroughs and fight other armoured formations . Well into the 1930s , some soldiers saw tanks as merely serving in support roles for large conscript armies of foot soldiers and horse cavalry . But even before the end of the First World War , some military theorists such as J . F . C . Fuller , and later Basil Liddell Hart , formulated a different image of combined - arms armoured warfare , featuring independent , professionally manned tank units . The conditions of the Treaty of Versailles forced Germany to build an armed forces essentially from scratch , allowing it to more easily abandon conservative theories and develop Blitzkrieg tactics . The infantry and cavalry tank roles were abandoned by the end of the Second World War . World War II tanks were generally classified by weight and role : fast , relatively inexpensive " light tanks " for reconnaissance , general - purpose " medium tanks " , and slow " heavy tanks " for breakthroughs and long - range fire . Combat experience helped weed out unsuccessful designs . After World War II , less expensive armoured car s and more specialised tracked vehicles gradually took over the reconnaissance role . Heavy tanks were shown to be incapable of keeping up with mobile warfare , but advances in engine , weapon , and armour technology allowed medium tanks to acquire the best characteristics of heavy tanks — the ultimate in mobility , firepower , and protection were rolled into the main battle tank ( MBT ) . Tank generations . Tanks are sometimes classified as belonging to a particular generation , although the actual definition and membership in these generations is not clearly defined . Soviet and Russian military planners organise tanks into a generation of tanks up to 1945 , and four generations of main battle tanks , while Canadian strategists organise main battle tanks into three generations . The military of the People ' s Republic of China also recognises three generations of its own tanks . Size . There were many names given to different tank types , and similar names did not assure similar design goals . Some light tanks were relatively slow , and some were fast . Some heavy tanks had large - calibre , low - velocity , anti - infantry bunker - busters , and some had high - velocity anti - tank guns . WWI . In World War I , the first tank , the Mark I , was designed for supporting infantry by crossing trenches and attacking machine - gun posts . Initially , there were two types with two roles : the ' males ' , armed with artillery guns , and the supporting ' females ' , armed with anti - infantry machine guns to protect the ' males ' . The tanks that followed were described relative to it , including light , medium , and super - heavy tanks — for example , the light tank FT - 17 ( approximately 7 t / 15 , 000 lb . ) and the medium Medium Mark A ' Whippet ' ( 14 t / 31 , 360 lb . ) . By the end of the war , the Mark I ( ~ 30 t / 56 - 60 , 000 lb . ) could be classified as a medium tank , and the Whippet as a light tank . Super - heavy breakthrough tanks such as the Char 2C ( 69 t / 158 , 000 lb . ) or the K - Wagen ( 120 t / 275 , 000 lb . ) were nearly completed before the war ended . In comparison , the current British MBT , the Challenger 2 , weighs some 60 t ( 137 , 500 lb ) . WWII . Tank models were developed before and during World War II according to different philosophies , with different combinations of armour , mobility , and armament . Each major nation developed its own doctrine of tank use , and therefore different tank models to suit . New doctrines explored the role of the tank as a fast - striking unit , while technological improvements led to the invention of engines , tracks , transmission , and suspension , which made tanks more reliable over a long distance . The ideas of the American inventor Walter Christie were important in establishing the fast tank concept . Tank doctrine in the UK declared that one group of tanks would accompany infantry in a similar role to World War I , while another group of ' cruiser ' tanks would then exploit a breakthrough , in a role similar to cavalry . In the USSR , 1930s ' tank doctrine specified three groups of tanks : one ' breakthrough ' tank in the infantry support role , one tactical breakthrough tank to clear the combat area , and a ' fast tank ' for operational maneuver . In Germany , the ideas of Guderian established the need for unified tank formations , but with a mixture of armaments for differing roles . In the USA , doctrine evolved so that the main purpose of the tank was to provide infantry support and exploitation of breakthroughs . The antitank role was given to tank destroyers . There was no analog to the cruiser tank in pre - war US doctrine . There were those within the US Army which advocated a more modern force with tanks in the cavalry role , but their suggestions were not put into place by the time of the US ' s entry into World War II . These doctrinal differences are important when considering World War II tank classifications . Light tank . Light tanks tend to be smaller , faster , and lighter vehicles , and cheaper to produce . The weight of a ' light ' tank increased markedly during World War II . For example , the M24 Chaffee was a purpose - built light tank of late World War II , but weighed more than the Panzer III , a mainstay medium tank from 1939 - 43 but obsolete at the time the Chaffee was introduced . Some light tanks are able to move over land rapidly compared to heavier tanks and are maneuverable through obstacles such as jungle thickets , while maintaining lethality against enemy infantry . The Imperial Japanese Army exploited this ability of their light tanks during the Battle of Malaya . However , many other light tanks are no more mobile than their heavier cousins , in part because the emphasis on economy meant they often were powered by standard light truck engines rather than the larger , heavier , but much more powerful medium tank engines . Light tanks were quite common at the start of World War II , being the main element of German , Polish and French formations in the Polish and French campaigns , but during the war were relegated to reconnaissance roles because of the increasing firepower of tanks and anti - tank weapons . Some were amphibious , and some , like the Tetrarch , were small enough to be airlifted to battle . They were often preferred over armoured cars for scouting . The Soviet Union even built an experimental winged tank which ultimately was never put to practical use . The USSR experimented with giving infantry units detachments of light tanks ( e . g . , the T - 70 ) to provide armoured support . The idea was a failure because the tanks ' armour was readily penetrated by German anti - tank weapons , and their firepower was inadequate for fighting other tanks or destroying field fortifications . They were replaced in this role by the SU - 76 self - propelled gun . The French World War II - era light tank ( " Char Léger " ) types differed from other nations ' light tanks of the period . Since they were intended to be used for infantry support rather than scouting , they were slower than most light tanks , giving it the weaknesses of the type , but with heavier armour . The French intended the AMR scout tanks ( " Automitrailleuses de Reconnaissance " ) and armoured cars ( " Automitrailleuses de Combat " ) for scouting and light combat roles . Since World War II , light tanks have continued in the reconnaissance role , thanks to their modest cost and potential for amphibious capabilities , but have been supplemented by infantry carriers and armoured cars in many roles . Medium tank . Medium tanks are simply neither the heaviest nor lightest in weight , and many of the designs had successful balance of firepower , mobility , protection , and endurance , and could often be adapted to a variety of roles . Medium tanks of the intra - war period included the British Vickers Medium Mark II and the Soviet multi - turreted T - 28 . There were medium tanks that focused on anti - infantry capabilities ( such as in World War II : the Panzer IV short - barrel , and the M4 Sherman ) , and medium tanks which were more focused on the anti - tank role , mounting high - velocity tank gun s . The French cavalry tanks ( " Chars de Cavalerie " ) focused on speed in addition to power and protection of the other designs . They were similar to what other countries called medium tanks . When Soviet tank designers were preparing a successor to the BT Fast Tank series , they combined its excellent mobility with thick , sloped armour and the unprecedented firepower of a 76 - mm high - velocity gun . The result was the T - 34 medium tank , whose superbly balanced capabilities shocked the German Wehrmacht when it invaded the Soviet Union . The lessons of Blitzkrieg , first employed by the Germans and eventually adopted by other nations , found their best expression in formations of mutually - supporting medium tanks and motorised infantry . The traditional view of infantry and cavalry tank roles was rendered obsolete . As well , the Soviet Union and the United States both benefited from their ability to manufacture a well - balanced medium tank in incredible numbers — about 57 , 000 T - 34s and 49 , 000 Sherman tanks were built during the war . During and after the war , the roles of light tanks were gradually taken over by less - expensive armoured cars and specialised reconnaissance vehicles . Heavy tanks , having shown their limitations in World War II , experienced a limited arms race of progressively more heavily - armed and armoured designs , but these too were eventually phased out in favour of increasingly capable and flexible medium tanks . Simpler and more economical self - propelled gun s , and later anti - tank guided missile s , came to fulfill fire - support and anti - tank roles , allowing tanks to become more specialised for mobile warfare . Heavy tank . Heavy tanks have usually been deployed to fulfill the need for a breakthrough tank , though in practice have been more useful in the defensive role than in the attack . Design goals have included attacking obstacles , creating breakthroughs , and engaging enemy armoured formations . They feature very heavy armour and weapons relative to lighter tanks , though they tend to push power plants to the limits . As a result they tend to be either underpowered and comparatively slow , or have engine and drive train problems from overworking their engines . The first tank , the Mark I of World War I , was designed around this philosophy . So was the Char 2C , one of the largest tanks ever produced . At the start of World War II , the French and the Soviets were the only countries to have inventories of heavy tanks , such as the Char B1 , T - 35 , and KV - 1 . The Matilda II infantry tank , though not as heavy as the others , had thicker armour than most tanks in service at the time . Later war examples were the German Tiger I and II , as well as the Soviet IS series . Note that " heavy " versus " medium " is more a question of tactical roles than weight ; the Pz . Kpfw . V Panther , for example , was a " medium " tank that outweighed most Allied " heavy " tanks . Heavy tanks achieved their greatest successes both fighting other , lighter tanks , and destroying fortifications with their very large guns . Although it is often assumed that heavy tanks suffered inferior mobility to mediums , this was not always the case , as many of the more sophisticated heavy tank designs featured advanced suspension and transmission precisely to counteract this drawback . But the greatest drawback is cost which translates into production , resulting in short supplies . The German Tiger , for example , had similar speed and better terrain - handling characteristics when compared to the significantly lighter Pz IV medium tank , albeit at the cost of low reliability and only 1 , 355 were produced compared to 58 , 000 Soviet T - 34 and 40 , 000 American M4 Sherman medium tanks . The immediate post - war period saw the final fielding of heavy tanks , including the US M103 heavy tank , the British FV214 Conqueror , and the French ARL 44 , all in response to the Soviet heavy tanks of the period . The largest tank guns were approaching maximum calibre whose shell could still be handled by the crew , even using awkward two - part shells and propellants , which greatly slowed their rate of fire . Thanks to improved gun designs and fire control technology , postwar medium tanks were catching up to heavy tanks in firepower . The tactical value of heavy tanks thus declined to the point that no new designs were fielded ; the heavily - armed mediums came to be known as the Main Battle Tank ( MBTs ) . Less expensive self - propelled artillery pieces could fulfill the heavies ' infantry support role . Heavy tanks were finally rendered obsolete by anti - tank guided missile s and high explosive anti - tank ( HEAT ) ammunition . The much more flexible missiles are effective at ranges beyond a tank gun ' s range , and sheer armour mass was no longer a guarantee of survivability against the largest HEAT warheads of tank guns or missiles . Super - heavy tank . There were a few rare tanks informally called " super - heavy tanks " . As their name implies , most of these tanks were extremely heavy such as the impractical , Porsche - designed German Panzer VIII Maus . Super - heavy tanks featured very thick armour and more powerful weapons than could be mounted on other vehicles . Most of these super - heavy tanks only reached pre - prototype stage , while some never even left the drawing board , such as the Landkreuzer P . 1000 Ratte , Landkreuzer P . 1500 Monster and TG - 5 tank designed by Edward Grote . World War II and the following post - war period saw the quick zenith of super - heavy tanks with the conception of the German P - series tanks , British experimental Tortoise tank and US T - 28 Super Heavy Tank . The super - heavy tank concept was short - lived since these designs were simply too heavy to be of practical military value . Modern . Light tank . Light tanks , such as the PT - 76 , continue to play an important role in tank warfare , although many are losing favor to cheaper , faster , lighter armoured cars . The light tank still fills an important niche in many armies , especially nations with airborne divisions , or those which do not have the resources and funding to maintain a large number of main battle tanks . Additionally , they have important advantages over heavier tanks in Southeast Asia and other nations in the Equatorial region . Their size allows them to maneuver through thick rainforests and their weight reduces the risk of getting stuck in muddy terrain . This makes the light tank the preferred choice for infantry support in Equatorial nations . Main battle tank . Advances in tank design , armour , and engine technology allowed tank designers to increase the capabilities of tanks significantly without always resorting to heavier designs , although weights did gradually increase . High explosive anti - tank ( HEAT ) ammunition was a threat to tanks and could penetrate steel armour thicker than was practical to put on a tank . Advances such as the British - designed Chobham armour limit the effectiveness of weaker HEAT rounds , but the vulnerability still remained . On 7 November 1950 , the US Ordnance Committee Minutes ( OCM ) , order # 33476 , ceased utilizing the terms heavy , medium , and light tanks and redesignated tanks by the gun system , e . g . " 90mm Gun Tank M48 Patton " , etc . with heavy gun tanks ( 120mm ) , medium gun tanks ( 90mm ) , and light gun tanks ( 76mm ) , although these gun terms were often still shortened to simply heavy , medium , and light tanks . The term " main battle tank " , in the US , was first generally applied to the US M60 main battle tank in 1960 , coinciding with the deactivation of the US Army ' s last M103 heavy tank battalion , the 2nd Battalion , 33rd Armor Regiment , and the delivery of the M60 to US units in Europe . The M60 , armed with a 105mm main gun , was to be an all purpose tank , armed and protected as a heavy tank , but with the mobility of the medium tank . The MBT would form the backbone of modern ground forces . It is armed and armoured to face as many kinds of threats as possible , but especially direct hits from other tanks and lighter infantry anti - tank weapons . However , the threats to MBTs on a modern battlefield are numerous . Many Cold War MBTs evolved more or less directly from late World War II medium tank designs . The US Patton series of tanks was a series of successive evolutions of the M26 Pershing , for example , and the Soviet T54 / 55 was a direct descendant of the T - 44 , itself an evolution of the T - 34 . This meant that many MBTs retained something of their " medium tank " origins in terms of their balance of size , weight , mobility , and protection . However , in the 1960s and 1970s , a generation of purpose - designed main battle tanks appeared , starting with the British Chieftain tank . These vehicles are less obviously influenced by wartime templates ( the Chieftain , for example ) , weighing as much as a World War II Tiger tank and possessing far greater firepower and armour , while retaining the mobility of the previous Centurion design . Similarly , the US M1 Abrams series , the German Leopard 2 , the British Challenger and French Leclerc tanks are all main battle tanks . The defining feature of the main battle tank type is neither its weight , mobility , nor firepower , but instead the idea that only one type of heavily armoured vehicle is required to carry out the roles of breakthrough , exploitation and infantry support . Even heavily armoured MBTs are vulnerable to anti - tank weapons , which are often designed to attack their most vulnerable locations : the top , the bottom , and the tracks . Tanks also retain much of their vulnerability to artillery fire and mines . A tank ' s heaviest armour is concentrated on its front , leaving its sides and rear less well protected . The response was to focus on the traits that allowed the tank to survive ; protection , mobility and firepower . The amount of armour added was usually sufficient to stop at least previous - generation projectiles from penetrating . Armour on more advanced Western MBTs has been shown to deflect current generation projectiles at at least their frontal armour , but there is little public information on the armour levels of the latest MBTs , as such information is generally kept secret . Role . WWII . Infantry tank . The idea for this tank was developed during World War I by the British and French . The infantry tank was designed to work in concert with infantry in the assault , moving mostly at a walking pace , which required it to carry heavy armour to survive defensive fire . Its main purpose would have been to clear the battlefield of obstacles , suppress or destroy defenders , and protect the infantry on their advance into and through enemy lines by giving mobile overwatch and cover . One of the best - known infantry tanks was the Matilda II of World War II . Its armour was thick enough to stop all but the most powerful anti - tank rounds of the period . Its QF 2 - pounder gun was sufficient to take on most light and medium tanks of the early war , but could not fire high - explosive ammunition . It should not be confused with the Matilda Mk I , also an infantry tank , which however was armed with only a machine gun . The Churchill and Valentine infantry tanks were also successful models , some of which mounted heavier guns like the QF 6 - pounder . Cruiser tank . A cruiser tank , or cavalry tank , is designed to move fast and exploit penetrations of the enemy front . The idea originated in " Plan 1919 " , a British plan to break the trench deadlock of World War I in part via the use of high - speed tanks . This concept was later implemented in the " fast tanks " pioneered by Walter Christie . They were used by the United Kingdom during World War II . Cruiser tanks were designed to complement infantry tank s , exploiting gains made by the latter to attack and disrupt the enemy rear areas . Early models were thinly armoured because they were not expected to face deliberate defenses . They were armed with QF 2 - pounder anti - tank gun s that could not effectively combat infantry or towed anti - tank weaponry . Early cruiser tank designs , such as the A9 and A10 , were largely replaced by heavier cruiser designs such as the Crusader series , though in some cases by more modern light scouting tanks , such as the US M3 Stuart . In 1942 – 1943 , British cruiser tank units were reequipped with American M4 Sherman tanks . In 1944 , in replacing their tanks , a few units were partially converted back to British equipment : the Cromwell cruiser tank , which had the same gun as the Sherman , similar armour , but significantly more speed . The final development of the British cruiser tank line was the Comet , introduced in late 1944 , which was an effective medium tank on a par with the German Panther . Leading on from the Comet , the Centurion , would be one of the first MBTs . The Soviet fast tank ( " bistrokhodniy tank " , or BT tank ) classification also came out of the infantry / cavalry concept of armoured warfare and formed the basis for the British cruisers after 1936 . The T - 34 was a development of this line of tanks as well , though their armament , armour , and all - round capability places them firmly in the medium tank category . Modern . Specialist tank . Tanks have often been modified for special purposes . The most common is to provide armoured capability for combat engineer s . These include tanks carrying large - calibre demolition guns , with flail s or plough s for mine - clearing , or flame tank s armed with flamethrower s . The tank occasionally may lose its weapons and the chassis alone may be used , as in bridge - laying tanks . Notable among wartime examples which formed Hobart ' s Funnies was the Churchill AVRE , which was equipped with a weapon for destroying bunkers and other fortifications but also able to mount other equipment . Another important modification was the amphibious tank , such as the Sherman Duplex Drive ( DD ) . These designs were modified with waterproofing and propulsion systems , to be able to traverse open water . Their most notable usage was on D - Day . Many specialist tank roles have been assigned to other vehicle types , though many tank chassis are still used for a wide variety of vehicles , ranging from anti - aircraft roles to bridge layers . Unmodified tanks can be fitted with equipment , such as mine - clearing ploughs , to give them ancillary roles