Log size and splitter tonnage rating are closely related. The more pressure applied, the thicker (or wider) the log it can split. A few commonly used benchmarks are as follows: 4 tons will split a 6-inch log, 16 tons will split a 12-inch log, 30 tons will split a 24-inch log. This is just a general guide. Different species of wood split more or less easily, and seasoned wood often splits more easily than green wood.