The three differ mainly in where the constraint sits, and none of them is a general winner. A mains mower is limited by a cable you must walk around. A cordless mower is limited by the energy in the pack. A petrol mower is limited by what you are willing to maintain and hear.
What each constraint actually costs
A mains machine has the simplest ownership of the three — nothing to charge, nothing to drain, nothing to service beyond the blade. The cost is entirely in use: the cable has to be kept out from under the deck, and it decides the mowing pattern rather than the lawn doing so. In a garden that is one open rectangle this is a minor irritation. In a garden divided by beds, paths and a corner behind a shed, it is the reason the machine stays in the shed.
A cordless machine removes that and replaces it with an energy budget. Whether the budget is adequate is not a question about the mower; it is a question about the pack, and the two are frequently sold apart. A machine advertised at a low price on this shelf is very often supplied without a battery at all, and that convention has its own page here.
A petrol machine has no budget and no cable. It has an engine: fuel that goes stale over a winter, an air filter, oil, a pull cord, and a guaranteed sound power level that is the highest of the three by a clear margin. It is also the only one of the three that will cut a genuinely overgrown lawn without stopping.
What does not decide it
Lawn area decides less than the listings imply. The square-metre figure printed on every machine is an assumption with no publisher, and its derivation differs between the three types — on a cordless machine it is a battery calculation, on a petrol machine it is a positioning statement.
Cut quality does not separate them either. All three are built against the same pedestrian mower safety standard, none of which measures cutting, and the deck shape and blade matter far more than what turns them.
How this site handles it
Each of the four mower families here is compared within itself, on deck width, on mass, on what the listing states about the pack, and on the figures the maker actually publishes. A cross-family recommendation is a recommendation about your garden, and the pages say what they are assuming when they make one.
The questions that keep coming in
Is battery now as good as petrol?
On a domestic lawn the question is usually settled by the pack rather than by the motor. A cordless machine with a single small pack runs out before a large lawn is finished, and one with enough energy on board costs what a petrol machine costs. What has genuinely closed is the gap in cutting.
Does a longer cable solve a mains mower’s problem?
It moves the problem rather than solving it: a longer run means a larger voltage drop and a cable that has to be managed on every pass. The constraint on a mains mower is not reach, it is the person walking around the flex.
Last reviewed 26 September 2026