Petrol vs Electric Lawn Mower: Which Should You Choose?

Key takeaway: For most Australian suburban lawns under about 600 m², a battery mower is the better choice: it’s quieter, starts instantly and needs almost no upkeep. Petrol still wins on big blocks, thick kikuyu and grass that’s regularly left long, but rotary petrol mowers run at 84 to 94 dB(A), loud enough that hearing protection is normally recommended.

The petrol vs electric lawn mower question used to have an easy answer: petrol for anything serious, electric for a postage-stamp lawn. That’s no longer true. Battery mowers now handle most suburban backyards without fuss, and the real question is whether your lawn is one of the exceptions.

One note on words before we start. In Australia, “electric” covers two quite different machines: battery (cordless) mowers and corded mowers that plug into a power point. Most of this comparison is petrol versus battery, since that’s the choice most people are actually making. Corded mowers get their own section further down.

Petrol vs Electric Lawn Mower at a Glance

Factor	Petrol	Battery electric
Best lawn size	Large blocks, roughly 600 m² and up	Small to medium, up to roughly 600 m²
Long or thick grass	Strong; copes with kikuyu left for weeks	Fine if mown often; labours in long, wet growth
Noise	Rotary mowers measured at 84 to 94 dB(A)	Noticeably quieter; check the model’s rated noise
Starting	Pull cord, choke, sometimes several tries	Button or lever
Runtime	As long as the tank lasts, then a quick refill	Limited by battery; check the quoted area per charge
Upkeep	Oil, spark plug, air filter, fuel, carburettor	Blade, deck cleaning, battery care
Exhaust emissions while mowing	Yes	None at the mower
Weight	Heavier	Usually lighter

The rest of this post explains each row, with the sources behind the numbers. If you’re still deciding between rotary and cylinder blades as well, start with the guide to the types of lawn mowers.

1. Power: Where Petrol Still Earns Its Keep

Power matters most when the grass fights back. Kikuyu in a Brisbane or Sydney summer can put on serious growth in a week, and buffalo left for a fortnight gets dense and wet underneath. A petrol engine keeps the blade speed up through that load. A battery mower slows down, draws harder on the battery and often leaves a ragged cut.

So the honest answer to “are battery lawn mowers any good?” is yes, if you mow often. Weekly mowing in the growing season keeps each cut light, which is exactly the job a battery mower does well. Let it go three weeks and you’ll want petrol, or you’ll be mowing twice at different heights.

Lawn size is the other half of it. As a working guide rather than a rule, battery mowers suit lawns up to roughly 600 m² on one or two batteries. Beyond that, you’re either buying spare batteries or stopping mid-mow to recharge. Petrol just refuels in a couple of minutes and keeps going.

2. Noise: The Difference You Notice First

WorkSafe WA measured rotary mowers at 84 to 94 dB(A), depending on whether the engine is two-stroke or four-stroke, its condition and its speed. Because that can top 85 dB(A), the level at which workplace hearing protection kicks in, it notes that hearing protection is normally used. The same guidance says four-stroke mowers tend to be quieter than two-strokes.

Battery mowers are quieter because there’s no engine, only a motor and a spinning blade. The difference is obvious from the first pass. It also matters to your neighbours, though it doesn’t change the rules: mowing hours apply to power garden tools generally, and they’re set by your state and council. NSW EPA points residents to time restrictions for domestic equipment, and our state-by-state guide to mowing hours covers the rest.

3. Emissions: More Than Most People Realise

Small petrol engines are dirtier than their size suggests. The California Air Resources Board found that running a commercial lawn mower for one hour emits as much smog-forming pollution as driving a new car about 300 miles, which is roughly 480km. That’s a commercial machine, so a home mower will differ, but the gap is the point: small engines lack the emission controls a car has.

Australia has tightened this too. Since 2020, new petrol mowers supplied here must meet the federal Product Emissions Standards for spark-ignition engines of 19 kilowatts or less. A battery mower produces no exhaust at the mower, although the electricity used to charge it still comes from somewhere.

4. Maintenance and Running Costs

A petrol mower needs an oil change, a spark plug, an air filter and fresh fuel, and two-strokes need the right petrol and oil mix. WorkSafe WA’s guidance points out that a poorly maintained mower runs at higher revs and makes more noise. Old fuel left in the tank over winter is the classic reason a petrol mower won’t start in September.

A battery mower’s upkeep is mostly the blade and keeping the underside of the deck clean. Both types need a sharp, balanced blade, and both cut badly without one.

Worked example: how much energy does a charge use?

Battery energy is easy to work out from the label. The formula is: voltage × amp-hours = watt-hours. A 36V, 5Ah battery holds 36 × 5 = 180Wh, or 0.18 kWh. Find the cost per kWh on your electricity bill, multiply by 0.18, and that’s the cost of a full charge. It’s a small fraction of a single tank of petrol for most households.

That calculation also shows why voltage alone tells you little. A 36V, 2Ah battery holds only 72Wh, well under half the energy of the 5Ah pack, so it mows far less lawn per charge.

5. Battery Safety and Lifespan

Lithium-ion batteries are safe when you treat them properly, and a fire risk when you don’t. SafeWork NSW advises using the charger designed for that battery and voltage, not leaving batteries charging unattended or for long periods, and checking for swelling or damage. Store them cool and dry, which rules out a hot tin shed in January.

At the end of its life, a lithium-ion battery can’t go in the household rubbish or recycling bin. Tape the terminals and take it to a battery recycling drop-off.

Batteries also wear out. Every charge cycle reduces capacity a little, so a five-year-old battery mows less lawn than it did new. Check the battery warranty separately from the mower warranty before you buy, because they’re often different lengths.

6. Corded Electric Mowers: Cheap, Light and Limited

Corded mowers are the lightest and simplest of the lot, with no fuel and no battery to wear out. The catch is the lead. Energy Safe Victoria advises keeping the cord of an electric lawn mower away from the blade, switching off at the plug immediately if it’s damaged, and not repairing it yourself. It also warns against using extension leads in wet areas unless they’re designed for it.

In practice that makes corded mowers a small-lawn tool, best near a power point and never on wet grass.

Petrol vs Electric Lawn Mower: The Verdict

Small lawn near a power point, under about 150 m²: corded or a small battery mower.
Typical suburban lawn of 150 to 600 m², mown weekly: battery. This is most Australian backyards.
Same size, but mown fortnightly or less: petrol, or a high-capacity battery system.
Over 600 m², or thick kikuyu that often gets away: petrol, or a battery mower with a spare pack.
Steep or rough ground: petrol self-propelled, since battery self-propelled models drain faster on hills.

If none of those fit cleanly, mowing frequency is the tiebreaker. People who mow often are happiest with battery. People who mow when they get around to it are happiest with petrol.

Common Mistakes When Choosing

Comparing voltage alone. Watt-hours (volts × amp-hours) tell you how much lawn a charge covers.
Buying petrol for a small lawn out of habit. You pay in noise, fuel and maintenance for power you’ll never use.
Buying battery for a lawn you’ll let go. Long, wet kikuyu will drain it fast and leave a poor cut.
Forgetting the second tool. If you already own a battery whipper snipper, a mower on the same battery platform saves buying extra packs.

Is a petrol or electric lawn mower better?

Neither is better everywhere. Battery electric suits most suburban lawns up to roughly 600 m² that are mown regularly, while petrol is better for large blocks and grass that’s often left long.

Are battery lawn mowers any good?

Yes, for regularly mown small to medium lawns. They’re quiet, easy to start and low maintenance. They struggle mainly with long, thick or wet grass and with very large areas on a single battery.

Is it okay to cut wet grass with an electric lawn mower?

Avoid it with a corded mower. Energy Safe Victoria warns against using extension leads in wet areas unless they’re designed for it. Wet grass also clogs any mower and gives a poor cut, so wait for it to dry where you can.

Are petrol mowers louder than electric?

Yes. WorkSafe WA measured rotary mowers at 84 to 94 dB(A), above the 85 dB(A) level where hearing protection is normally used. Battery mowers are noticeably quieter, though you should still check the model’s rated noise.

How long do lawn mower batteries last?

They gradually lose capacity with every charge cycle, so runtime drops over the years. Check the battery warranty, which is often different from the mower’s, and store batteries cool and dry to slow the decline.

For the wider picture on mower types, blades and clippings, see the types of lawn mowers guide. Once you’ve picked one, how to mow your lawn properly covers heights for buffalo, kikuyu and couch. For specific models, the best lawn mowers guide narrows the field, and everything else is in the mowers hub.

Sources