Five years ago, this was a straightforward conversation. Petrol mowers were more powerful, ran longer, and handled tough grass better. Battery mowers were convenient but underpowered — fine for a small, tidy lawn and not much else.

In 2026, that gap has narrowed dramatically. Battery technology has improved to the point where a good cordless mower will handle 90% of UK gardens without breaking a sweat. But petrol still has its place, and buying the wrong type for your situation is an expensive mistake.

Here's an honest comparison based on real-world use, not spec sheets.

Battery Mowers in 2026 — Where They've Caught Up

Modern brushless motors and high-capacity lithium-ion batteries have transformed cordless mowers. The current generation from brands like EGO, Greenworks, and Milwaukee offers:

• Genuine power — brushless motors deliver torque comparable to mid-range petrol engines. They handle thick, damp grass without bogging down
• 40–60+ minute runtimes — a 5.0Ah 56V battery typically gives 40–50 minutes, which is enough for most gardens up to around 400m²
• Near-silent operation — a massive quality-of-life improvement, especially in built-up areas or if you mow early mornings
• Zero ongoing fuel costs — just plug in and charge
• Virtually no maintenance — no oil changes, no spark plugs, no air filters, no carburettor cleaning

Where Petrol Still Wins

Petrol isn't dead. For certain situations, it remains the better tool:

• Large gardens (500m²+) — runtime isn't a concern. Fill the tank and keep going. A petrol mower for large gardens will run for hours on a single tank
• Thick, overgrown grass — petrol engines sustain power through heavy loads better than batteries under maximum draw
• No recharge downtime — refuel in seconds vs 30–60 minutes to recharge a battery
• Wider cutting widths — many petrol mowers offer 46–53cm decks, whereas most cordless models top out at 46cm
• Lower upfront cost (sometimes) — a capable petrol mower starts around £200, while an equivalent cordless setup with battery and charger often starts at £300+

Runtime Comparison

Runtimes are approximate and depend on grass condition, cutting height, and mowing speed. Wet or thick grass reduces battery runtime by 15–20%.

Cost Comparison Over 5 Years

The upfront price difference isn't the whole story. Here's a realistic cost breakdown over five years for a mid-range model in each category:

Over five years, the total cost of ownership is remarkably similar. The battery mower costs more upfront but saves on fuel and servicing. The big variable is the replacement battery — if your battery lasts the full five years (some do), the cordless option works out cheaper overall.

Maintenance Comparison

This is where cordless really pulls ahead for people who don't enjoy maintenance.

A petrol mower needs a proper annual service — oil, plug, filter, fuel system check. A cordless mower just needs the blade done and the deck cleaned. For people who want to mow the lawn and not think about it the rest of the time, that difference matters.

Noise Levels

This often gets overlooked, but it's a genuine quality-of-life factor.

• Petrol mower: 85–95 dB — you need hearing protection, and your neighbours will know you're mowing
• Battery mower: 60–75 dB — conversational volume. You can mow early on a Sunday without anyone caring

If you live in a terraced or semi-detached house with close neighbours, the noise difference alone might swing your decision.

Which Should You Buy?

Buy a battery mower if:

• Your garden is under 400–500m²
• You want minimal maintenance
• Noise is a concern (neighbours, early mowing, etc.)
• You already own batteries in the same platform (EGO, Makita, etc.) — sharing batteries across tools saves significant money
• You want a mower that starts every single time, first press

Buy a petrol mower if:

• Your garden is over 500m² or has slopes and thick grass
• You need extended runtime without recharging
• You don't mind annual servicing
• You want the widest cutting width options
• Budget is tight — decent petrol mowers start cheaper than equivalent cordless setups

The Bottom Line

For the average UK garden — say 100–400m² of relatively flat lawn — a cordless mower is now the smarter buy in 2026. The technology has caught up, the running costs are lower, and the convenience of press-button starting with zero maintenance is hard to argue against.

But if you've got a big garden, or you mow professionally, or you just prefer the feel and sound of a petrol engine — it's still a perfectly valid choice. The best mower is the one that fits your garden and your patience for maintenance. Don't let anyone tell you otherwise.