How we test lawn mowers

Our recommended Best Buy lawn mowers take the hard work out of mowing the grass. They blitz through long and damp grass to leave your lawn looking smart, and they're easy to use.

Our field tests and reviews of corded electric, cordless battery, petrol, hand-push and cylinder mowers are designed to sort the outstanding models from the poor mowers that require too much effort and leave your lawn looking messy.

Read on to find out the lengths we go to in the Which? field tests to find the best lawn mowers. Our reviews answer all the most crucial questions about lawn mowers, including:

• How well will it mow my grass?
• Will it leave grass clippings everywhere?
• Is the lawn mower easy to use?
• How close to the lawn edges will it mow?
• Can it tackle long grass?
• Should I buy it?

Go straight to our lawn mower reviews to discover the best and worst models. To find out more about our testing, read on.

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Video: how we test lawn mowers

Watch the video to find out what we look for in a lawn mower, and what makes the best models the quickest and easiest to use.  

We carry out independent, scientific tests designed to find out how well lawn mowers cope with challenging situations and how easy they are to use. 

Best lawn mowers 2023: We've tested and rounded up the best lawn mowers, from lower-priced options to high-end brands

How well will it mow my lawn?

We test each different type of lawn mower on a range of grass, from a short, ornamental lawn to rough meadow grass.

When testing lawn mowers, we measure how much time and effort it takes to mow a lawn, as well as how well the mower collects the grass clippings and fills up the grass box.

We rate how closely it cuts up to the edges of the lawn to reach the tricky bits of longer grass. 

We have a range of testers who rate the mower on how manoeuvrable it is and how easy it is to use.

Our ease-of-use tests cover how easy the lawn mowers are to set up ready for use (eg setting the cutting height and handle height), how comfortable the operating position and controls are, how easy it is to push the lawn mower around the lawn and manoeuvre around obstacles, how easy the grass collector is to use, and how easy the mower is to clean and store after use.

Will the lawn mower collect all my grass clippings?

There are big differences in how neat lawn mowers leave the lawn after mowing. Some models collect all the clippings, but others leave clumps of grass on your lawn or scatter the clippings far and wide.

Check the star ratings in the test results section of our lawn mower reviews to see how different models compare.

It’s also helpful to know how well collecting mowers fill their grass boxes. We’ve come across lawn mowers that only fill the grass box half full before they need emptying, which is why each of our reviews shows you the true capacity of the grass box for each collecting lawn mower we've tested. 

Discover the best lawn mower brands according to our field tests and surveys of owners.

Is the lawn mower easy to use?

A great lawn mower should take the hard work out of cutting your grass. Some are much easier to use than others, so we carry out tests and checks to find out which will help you to mow your lawn without any hassle, and which will give you a hard time.

• We weigh the lawn mowers so we can tell you the weight you’ll have to lug around.
• We check how easy (or not) it is to assemble and disassemble each lawn mower, including removing, replacing and emptying the grass box, and how easy the mower is to store.
• We test the convenience of using the controls and manoeuvring the mower around obstacles, as well as how much cleaning the mower needs.
• Finally, we note other essentials such as how the how long the cable is, how long the battery lasts (if there is one), and how easy it is to change the cutting height.

Our overall ease-of-use star rating takes these factors into account so you can see at a glance how easy a lawn mower is to use.

The rating also takes account of feedback from our gardening experts about how easy the models were to use. Check the test results page of each lawn mower review to see star ratings for overall ease of use.

How well will the lawn mower deal with edges?

Depending on where the wheels are and how manoeuvrable a lawn mower is, it might be able to cut grass lying flat over lawn edges or growing up again a wall or fence - or it might leave you reaching for your strimmer.

Our tests assess how closely the mowers cut grass that's been left to grow along paths and borders, and around trees and walls.  

We use each lawn mower on 15 metres of each type of edging and rate the finish. We’ve found some lawn mowers that leave you with up to 5cm of uncut grass.

Will the lawn mower be able to cope with tough mowing jobs?

If you've got a lot of long grass to cut, in a meadow or orchard, or just a very large lawn, you might be thinking of buying a petrol mower. 

But being powerful and cable-free doesn't mean a petrol mower will be able to tackle all the jobs you might throw at it. If you've got a really large area to mow, look for a self-propelled machine so that pushing it through the grass won't be a chore. 

Make sure it has a large grass box that fills well, or a mulching option, so you won't have to make lots of trips to the compost heap. We assess how easy each petrol mower is to start, both from cold and after it's been running for a while. We also check it's got enough power to cut through long grass and tough, clumpy meadow grass.

Pick the right lawn mower for your needs using our lawn mower reviews. 

Can I replace the battery?

Lithium-ion batteries always deplete and eventually die over time. At Which?, we believe that cordless products should last longer than the batteries they come with. That's why we no longer make cordless lawn mowers Best Buys if spare batteries aren't available from the manufacturer – no matter how good the lawn mower might be.

Should I buy it?

Each of the assessments described above goes part way to making up a total test score, which is the percentage figure we award each lawn mower. But certain assessments are more important than others, and so carry different weights:

Cordless lawn mowers:

• 50% Grass cutting ability
• 30% Ease of use
• 5% Quality of features
• 5% Battery life
• 5% Noise
• 5% Energy consumption

All other lawn mower types:

• 51% Grass cutting ability
• 31% Ease of use
• 6% Quality of features
• 6% Noise
• 6% Energy consumption

The percentage scores each type of lawn mower needs to get to be a Best Buy are:

• Cordless lawn mowers - 73%
• Electric lawn mowers - 70%
• Petrol lawn mowers - 75% 

Don't Buy lawn mowers score under 45% in our tests.

What is a Which? Eco Buy lawn mower?

If you want to make the most sustainable choice when next buying a lawn mower, an Eco Buy is for you.

Eco Buy lawn mowers will have a lower impact on the environment over their lifetimes than other lawn mowers. 

We calculate this by looking at how reliable the lawn mower’s manufacturer is and how easy it is to maintain the mower, to get an idea of how long-lasting it’s likely to be. We also look at how energy efficient it is, as well as its battery life. 

To become an Eco Buy, a lawn mower must have:

• A total test score of at least 65%
• Be an electric model - either corded or cordless, but not powered by petrol. 
• Four stars and above for grass-cutting ability
• Four stars and above for energy efficiency
• Four stars and above for battery life (cordless models only)
• Three stars and above for noise ratings - to minimise noise pollution and the disruption of local ecosystems
• Its brand must get a good reliability rating in our annual lawn mower owners survey 
• We must be satisfied with its build quality and ease of maintenance in our expert assessments.

Only between 5-10% of lawnmowers are sustainable and effective enough to be Eco Buys. To find out which qualify, head to our lawn mower reviews and use the Eco Buy filter.

What is the future for petrol-powered lawn mowers? 

With sales of new petrol and diesel cars set to be banned by 2030, could petrol gardening tools be next?

By improving the appearance of outside spaces, we may be inadvertently contributing to environmental damage.

Unlike cars, petrol garden machinery doesn’t have catalytic converters to reduce the amount of pollutants that enter the atmosphere - likely due to the cost of materials bumping up the retail cost, and because UK regulations are not as strict for garden tools.

Over in California, Governor Gavin Newsome has signed legislation banning the sale of petrol gardening equipment by 2024.

We're already seeing less petrol launches from manufacturers, who appear to be focussing their attention on cordless tools. Cordless tools produce zero emissions and are quieter, offering a better option for the environment and our health.

We’re finding that cordless tools are now rivalling petrol in their power and, in some cases, out-performing, so many consumers have already made the switch.