They are not alternatives: a deck needs the power to drive it, and the mismatch is the fault to look for. A wide deck on a weak motor is the commonest bad buy on this shelf.
Why they have to be read together
A mower blade does two jobs. It cuts, which takes relatively little, and it moves air, which takes a great deal — the lift that stands the grass up before the edge reaches it, and the flow that carries clippings into the catcher. Both scale with blade length and with the square of tip speed.
A longer blade therefore asks for more torque simply to hold its speed, before any grass is involved. When the motor cannot, the blade slows, the lift collapses, the grass lies down instead of standing up, and the cut becomes a tear. That is what a bogging mower is doing.
Why the power figure does not settle it
On a mains machine the number in the listing is the rated input — the electricity the machine draws from the socket. It is not the work delivered at the blade, and the losses between the two differ between machines. This site prints it and calls it an input.
On a petrol machine you get a displacement and often a horsepower figure, and neither is obtained the way an electric rating is. Comparing 1800 W against 4 PS is not a comparison.
On a cordless machine there is frequently no power figure at all — just a platform voltage and a pack capacity, neither of which is power.
What is worth reading instead
Deck width against machine mass, which is the closest thing to an honest proxy on this shelf: a maker that has put a wide deck on a serious machine has also put weight under it.
And what the listing says about the conditions. A machine described for short, maintained grass and a machine described for rough ground are two different products even at the same width, and the description is sometimes the only place the difference appears.
How this site handles it
Mower pages print deck width, mass, and whatever power figure the maker publishes, each labelled with what it is — an input, a displacement, a claimed output. None of them is combined into a score, because the arithmetic that would justify combining them is not published by anyone.
Wherever this page and the maker’s own documentation disagree, the documentation wins. Every cutting width, cutting height, stated area, pack capacity, flow rate, head, sound level and application rate on this page comes from the maker’s own published figures, with the unit as printed and the source named. None of it is measured here, and no figure is converted into another convention, because a converted number is a different number. And the distinction this page keeps: a stated area is a supposition about your lawn, not a property of the machine. No standards body defines it, no test produces it, and each maker derives it from an assumption it does not publish — a battery calculation on one shelf, a duty cycle on another. This page reports the figure, names the derivation its machine type usually uses, and never ranks two machines on it.
The questions that keep coming in
Is a 1800 W mower better than a 1400 W one?
It draws more electricity. What reaches the blade depends on the motor and the transmission, and two machines of identical input can differ in what they deliver. The figure is an input and this site labels it as one.
How do I compare a petrol engine with an electric motor?
You largely cannot. A displacement in cubic centimetres, a horsepower figure and a watt rating are three different quantities measured three different ways. What is comparable across the shelf is deck width, mass and what the machine is observed to do.
Last reviewed 26 September 2026