The most important thing to consider when buying a hammer is what job the tool will be used for. There are several types of hammers and each is suited to a particular use. Choosing the wrong hammer could damage both a project and the tool.

The hammer that most people recognize is called a claw hammer. It is the most common household hammer, and arguably the most common household tool in general. The head is a flat surface on one end to strike objects with and the opposite end is a curved claw. The claw is used for prying different materials or for pulling nails. They come in various weights, but the average home owner will most likely get the most use out of a 16 oz (.45 kg) hammer.

A rip claw hammer, also called a straight hammer, is very similar to the claw hammer. Instead of the curve, the claw on a rip claw hammer is straight to make it better suited to demolition work. They are also a heavier hammer ranging from 20-32 oz (.57-.91 kg).

Ball-peen hammers are used most often in engineering to shape metal and close rivets. The term "peen" refers to the process of shaping metal by hammering. The ball-peen hammer has a distinctive shape, with a round ball-shaped end and a flat head end. Other ball-peen hammers include the cross peen hammer which is useful for starting panel pins and setting tacks, and the chisel peen hammer which can be used for punching, riveting, and chiseling.

A tack hammer is sometimes also called a mounting hammer. These tools have magnetic heads that conveniently hold small nail or tacks. These are most often used in crafting, hanging pictures, and upholstery.

Sledge hammers are true heavyweights. They are very large and weighty with a double striking surface and are usually swung like an axe. They are intended for breaking concrete, driving stakes, and major demolition projects.

Some confuse mallets with hammers because of their similar shape. Mallets have heads that are softer than the metals usually used in hammers. Three common mallets are lump, carpenter, and jewelry. A lump mallet, which is faced on both ends like a small sledgehammer, is good for light demolition and driving heavy objects like masonry nails and chisels. A carpenter's mallet is used to drive chisels and tap joints while preventing damage to delicate wooden projects. Jewelry mallets are used for small and delicate metalworking.

When choosing a hammer, as with most tools, you get what you pay for. The cheapest hammers may not hold up to large amounts of work. Before purchasing, a consumer should pick up the hammer and make sure it is comfortable, fits in their hand, and is well balanced. If the hammer feels uncomfortable to hold and work with, it will only complicate any project that it is used for.