Log Splitter Tonnage Calculator: 4, 7 or 10 Tonne?

Tell the calculator about the hardest log you split, not the average one, and it will suggest the log splitter tonnage to look for, the type of machine, and whether your logs will fit the bed. The point most buyers miss: diameter and knots decide the force you need far more than whether the wood is green, and firewood generally splits more easily green than the same species fully seasoned.

How it works: the calculator places your log in a diameter band, picks the column that matches the wood (clean softwood and cooperative hardwood at one end, knotty or dense seasoned hardwood at the other), then applies two adjustments. Green oak, beech or hornbeam is treated as one step easier than seasoned, because the fibres have not hardened yet. Elm and fruit wood are bumped up a band, because their interlocked, stringy grain stalls machines that cope with everything else. The bands follow our log splitter tonnage guide.

Why the tonnage on the box is optimistic

There is no standard, regulated test for a log splitter's tonne rating. Makers usually work it out from the ram's bore area multiplied by the maximum hydraulic pressure, which is a theoretical peak the machine rarely reaches under load. That is why the calculator rounds up and why it is worth leaving some headroom above the figure it gives you.

Bed length and weight matter as much as force

A 4 tonne electric typically takes logs around 37cm long, and a good 7 tonne machine stretches to roughly 43 to 52cm depending on the model. If your logs are longer than the bed, no amount of force will split them. And once a round is too heavy to lift safely onto a waist-high bed, the answer is a vertical or petrol machine, not a bigger number on a horizontal one. Before you buy, compare the maximum log length and diameter in our log splitter buying guide, and read how to use an electric log splitter safely.

When a stalled splitter is not a tonnage problem

A single knot through the middle of a round can stop a 7 tonne machine that sails through a clean log twice the size. Before you blame the machine, turn the log so the wedge meets it away from the knot, split in from the edge rather than the dead centre, or cut the round shorter. For the odd piece of elm, a maul and a wedge will finish what the machine started: see how to split logs by hand.