A sledgehammer is a hand tool categorized as a hammer, but is considerably larger than a standard claw hammer or mallet. Due to the size of a sledgehammer, it is typically used for tasks that require more force than can be applied with a standard hammer. The handle of a sledgehammer is longer than a standard hammer and is typically made of wood. The head of a sledgehammer is usually metal and a sledgehammer may weigh as much as 20 pounds.

In contrast to a claw hammer or even a rubber mallet, a sledgehammer is not used for light duty tasks. Rather, the sledgehammer is designed for displacing a large amount of force over a small area. This is possible because of the larger head and longer handle. Though it takes a person of some strength to wield a sledgehammer with full force, the long swinging range and weight of the head allows for a larger impact.

Sledgehammers have been used in the construction industry for many years. When railroads were being built, the sledgehammer was a useful tool for driving railroad spikes. The sledgehammer is also deployed for driving rebar, the steel reinforcement often used in commercial concrete and masonry, as well as for busting up concrete and other demolition work. Sledgehammers are also useful for splitting large logs and pieces of wood when used in combination with a small handled axe.

The weight and handle length of a sledgehammer varies. Though mostly, a sledgehammer is a heavy weight hammer with a long handle, smaller sledgehammers weighing far less than 20 pounds are also available. Smaller sledgehammers are useful for medium duty tasks where a claw hammer is inadequate but a full size sledgehammer is too big, such as demolition in tight areas. Certain safety precautions should be employed when using a sledgehammer, including the use of safety goggles, a clear work area free of obstruction while swinging, and the stability of the handle and head should be checked before each use.