The Panzerkampfwagen IV (PzKpfw IV), commonly known as the Panzer IV, was a German medium tank developed in the late 1930s and used extensively during the Second World War. Its ordnance inventory designation was Sd.Kfz. 161.
The Panzer IV was the most widely manufactured German tank and the second-most widely manufactured German armored fighting vehicle of the Second World War, with some 8,500 built. The Panzer IV chassis was used as the base for many other fighting vehicles, including the Sturmgeschütz IV assault gun, Jagdpanzer IV tank destroyer, the Wirbelwind self-propelled anti-aircraft gun, and the Brummbär self-propelled gun.
The Panzer IV saw service in all combat theaters involving Germany and was the only German tank to remain in continuous production throughout the war. It received various upgrades and design modifications, intended to counter new threats, extending its service life. Generally, these involved increasing the Panzer IV's armor protection or upgrading its weapons, although during the last months of the war, with Germany's pressing need for rapid replacement of losses, design changes also included simplifications to speed up the manufacturing process.
The Panzer IV was partially succeeded by the Panther medium tank, which was introduced to counter the Soviet T-34, although the Panzer IV continued as a significant component of German armoured formations to the end of the war. The Panzer IV was the most widely exported tank in German service, with around 300 sold to Finland, Romania, Spain and Bulgaria.