How much tonnage or splitting force your log splitter has will determine how much and what kind of wood you can split. To achieve that, you’ll first have to measure the piston’s diameter, then square it, and then multiply it by 3.14. For instance, say that the diameter is 5 inches, you will have to multiply 25 by 3.14, which gives you 78.4. After that, divide it by 4. This will give you 19.625. To obtain the splitting force, you must take this result and then multiply it with the log splitter’s pressure rating. This would give you a total splitting force of 58,875 pounds if the pressure rating is 3000 PSI. To obtain tonnage, you must divide the result by 2000, which will give you a tonnage of 29.437 tons.