The U.S. Army designed the M4 as a replacement for the M3 Medium.
The designated goals were to produce a fast, dependable medium tank able to support infantry, provide breakthrough striking capacity, and defeat any tank currently in use by the Axis nations.
In April 1941 the U.S. Armored Force Board chose the simplest of five designs.
Known as the T6, the design was a modified M3 hull and chassis, carrying a newly designed turret mounting the Lee's main gun.
This became the Sherman.

The prototype M4 was completed in September 1941.
The T6 became standardized as the M4, and production after modifications began in October 1941.

The U.S. Army had seven main sub-designations for M4 variants during the production period: M4, M4A1, M4A2, M4A3, M4A4, M4A5, and M4A6.
These designations were manufactured concurrently at different locations.

While most Shermans ran on gasoline, the M4A2 and M4A6 had diesel engines: the M4A2 with a pair of GMC 6-71 straight six engines, the M4A6 a Caterpillar RD1820 radial.
These, plus the M4A4 which used the Chrysler A57 multibank engine, were mostly supplied to Allied countries under Lend-Lease. "
M4" can refer specifically to the initial sub-type with its Continental radial engine, or generically, to the entire family of seven Sherman sub-types, depending on context.
Many details of production, shape, strength, and performance improved throughout production without a change to the tank's basic model number; more durable suspension units, safer "wet" (W) ammunition stowage, and stronger armor arrangements, such as the M4 Composite, which had a cast front hull section mated to a welded rear hull.
British nomenclature differed from that employed by the U.S.
Early Shermans mounted a 75 mm medium-velocity general-purpose gun.
Although Ordnance began work on the Medium Tank T20 as a Sherman replacement, ultimately the Army decided to minimize production disruption by incorporating elements of other tank designs into Sherman production.
Later M4A1, M4A2, and M4A3 models received the larger T23 turret, with a high-velocity 76 mm gun M1, which reduced the number of HE and smoke rounds carried and increased the number of anti-tank rounds.
Later, the M4 and M4A3 were factory-produced with a 105 mm howitzer and a new distinctive mantlet in the original turret.
The first standard-production 76 mm gun Sherman was an M4A1, accepted in January 1944, and the first standard-production 105 mm howitzer Sherman was an M4 accepted in February 1944.


In June–July 1944, the Army accepted a limited run of 254 M4A3E2 Jumbo Shermans, which had very thick armor, and the 75 mm gun in a new, heavier T23-style turret, in order to assault fortifications.
The M4A3 was the first to be factory-produced with the HVSS (horizontal volute spring suspension) suspension with wider tracks to distribute weight, and the smooth ride of the HVSS with its experimental E8 designation led to the nickname Easy Eight for Shermans so equipped.
Both the Americans and the British developed a wide array of special attachments for the Sherman; few saw combat, and most remained experimental.
Those which saw action included the bulldozer blade for Sherman dozer tanks, Duplex Drive for "swimming" Sherman tanks, R3 flame thrower for Zippo flame tanks, and the T34 60-tube Calliope 4.5" rocket launcher for the Sherman turret.
The British variants (DD's and mine flails) were among "Hobart's Funnies," named after their commander, Percy Hobart of the 79th Armoured Division.

The M4 Sherman's basic chassis was used for all the sundry roles of a modern mechanized force: roughly 50,000 Sherman tanks, plus thousands more derivative vehicles under different model numbers.
These included M32 and M74 "tow truck"-style recovery tanks with winches, booms, and an 81 mm mortar for smoke screens; M34 (from M32B1) and M35 (from M10A1) artillery prime movers; M7B1, M12, M40, and M43 self-propelled artillery; and the M10 and M36 tank destroyers.

The M4 Sherman served with the U.S. Army and Marine Corps during World War II.
The U.S. also supplied large numbers to the various
The U.S. Army designed the M4 as a replacement for the M3 Medium. The designated goals were to produce a fast, dependable medium tank able to support infantry, provide breakthrough striking capacity, and defeat any tank currently in use by the Axis nations. In April 1941 the U.S. Armored Force Board chose the simplest of five designs. Known as the T6, the design was a modified M3 hull and chassis, carrying a newly designed turret mounting the Lee's main gun. This became the Sherman.
The prototype M4 was completed in September 1941. The T6 became standardized as the M4, and production after modifications began in October 1941.
The U.S. Army had seven main sub-designations for M4 variants during the production period: M4, M4A1, M4A2, M4A3, M4A4, M4A5, and M4A6. These designations were manufactured concurrently at different locations.
While most Shermans ran on gasoline, the M4A2 and M4A6 had diesel engines: the M4A2 with a pair of GMC 6-71 straight six engines, the M4A6 a Caterpillar RD1820 radial. These, plus the M4A4 which used the Chrysler A57 multibank engine, were mostly supplied to Allied countries under Lend-Lease. "M4" can refer specifically to the initial sub-type with its Continental radial engine, or generically, to the entire family of seven Sherman sub-types, depending on context. Many details of production, shape, strength, and performance improved throughout production without a change to the tank's basic model number; more durable suspension units, safer "wet" (W) ammunition stowage, and stronger armor arrangements, such as the M4 Composite, which had a cast front hull section mated to a welded rear hull. British nomenclature differed from that employed by the U.S.
Early Shermans mounted a 75 mm medium-velocity general-purpose gun. Although Ordnance began work on the Medium Tank T20 as a Sherman replacement, ultimately the Army decided to minimize production disruption by incorporating elements of other tank designs into Sherman production. Later M4A1, M4A2, and M4A3 models received the larger T23 turret, with a high-velocity 76 mm gun M1, which reduced the number of HE and smoke rounds carried and increased the number of anti-tank rounds. Later, the M4 and M4A3 were factory-produced with a 105 mm howitzer and a new distinctive mantlet in the original turret. The first standard-production 76 mm gun Sherman was an M4A1, accepted in January 1944, and the first standard-production 105 mm howitzer Sherman was an M4 accepted in February 1944.

In June–July 1944, the Army accepted a limited run of 254 M4A3E2 Jumbo Shermans, which had very thick armor, and the 75 mm gun in a new, heavier T23-style turret, in order to assault fortifications. The M4A3 was the first to be factory-produced with the HVSS (horizontal volute spring suspension) suspension with wider tracks to distribute weight, and the smooth ride of the HVSS with its experimental E8 designation led to the nickname Easy Eight for Shermans so equipped. Both the Americans and the British developed a wide array of special attachments for the Sherman; few saw combat, and most remained experimental. Those which saw action included the bulldozer blade for Sherman dozer tanks, Duplex Drive for "swimming" Sherman tanks, R3 flame thrower for Zippo flame tanks, and the T34 60-tube Calliope 4.5" rocket launcher for the Sherman turret. The British variants (DD's and mine flails) were among "Hobart's Funnies," named after their commander, Percy Hobart of the 79th Armoured Division. 
The M4 Sherman's basic chassis was used for all the sundry roles of a modern mechanized force: roughly 50,000 Sherman tanks, plus thousands more derivative vehicles under different model numbers. These included M32 and M74 "tow truck"-style recovery tanks with winches, booms, and an 81 mm mortar for smoke screens; M34 (from M32B1) and M35 (from M10A1) artillery prime movers; M7B1, M12, M40, and M43 self-propelled artillery; and the M10 and M36 tank destroyers.
The M4 Sherman served with the U.S. Army and Marine Corps during World War II. The U.S. also supplied large numbers to the various 
Tanks of the U.S. in the World Wars