What determines the size of a hammer?

The size of a hammer is primarily determined by the weight of the head. The weight influences the tool's effectiveness in driving nails and performing tasks such as demolition or framing. A heavier hammer head typically allows for greater force to be applied with less effort, making it easier to drive nails into tougher materials.

While the handle length can affect the handling and control of the hammer, it is the head weight that fundamentally defines the hammer's class and suitability for different tasks. A hammer with a lighter head may be better for delicate work, while one with a heavier head is often suitable for heavy-duty applications. The material of the handle and the brand may influence the overall quality or feel, but they do not define the size or the category of the hammer's effectiveness in the same way that the head weight does.