If you are going to split some woods and logs manually, you are most probably looking for a splitting tool right now. Chainsaws are out of the question because they require fuel and have chains that love to break. For manual splitting, a splitting axe or a maul is usually considered. Some people tend to consider the two as the same things, and sometimes the two terms are used interchangeably. However, there actually some differences that set a splitting axe and a maul apart. Sure, both are used for splitting woods and logs, but the different characteristics may affect your preference.
The most distinctive feature of a maul is the typical shape of the head. A maul has a V-shaped head. When if you see it from above, the head appears like a slice of pie. It is blunt and fat and heavy. The heavy mass creates more impact force for taking down monster jobs. The wedge head ends in a flat butt. The butt is wide, providing a lot of surface area for a sledgehammer. Sometimes, when splitting a particularly hard log, the maul gets stuck in the middle of the log. You can drive it down using a sledgehammer to assist. Another special distinction of a maul is that it always comes with a long handle. A maul is always a two-handed tool, and the entire swing should occur in the center plane of the swinger. The long handle also helps in leveraging the swing for maximum impact.
A splitting axe also has a wedge-shaped head, but it is relatively slimmer than the one of a maul. You can say that it is the less extreme version of a maul. It is also lighter. It can come with a long handle for two-handed use or a short handle for one-handed use. Due to being smaller and lighter, a splitting axe is somewhat easier to handle. It works quickly for the smaller wood pieces, and is excellent for turning small logs into kindling. However, you should not use it for monster jobs and particularly hard logs.
So, a maul should be your choice for splitting large and hard logs. It delivers much more impact force, and is typically a two-handed tool. On the other hand, a splitting axe is smaller and lighter, useful and practical for working on smaller logs and pieces.