How we test lawn mowers
Our recommended Best Buy lawn mowers take the hard work out of mowing the grass. They blitz through long grass 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?
Watch the video above to find out what we look for in a lawn mower, and what makes the best lawn mowers 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.
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 and 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 easily 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 each of our lawn mower reviews to see how different models stack up.
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 each grass box for each collecting lawn mower we've tested.
Is the lawn mower easy to use?
A great lawn mower should take the hard work out of cutting your grass. But some are much easier to use than others so we carry out tests and checks to find out which will help you 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 dissemble each lawn mower, including removing, replacing and emptying the grass box, and how easy the mower is to store.
- The convenience of using the controls and manoeuvring the mower around obstacles are also tested, as well as the amount of cleaning the mower needs.
- Finally, we note other essentials such as how the how long the cable is, the battery lasts if there is one, and how easily the cutting height can be changed.
Our overall ease-of-use star rating takes into account these factors so you can see at a glance how easy a lawn mower is to use. The rating also takes into account 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 may 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 that 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 15m of each type of edging and rate the finish. We’ve found some lawn mowers that leave you with up to five centimetres 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 may 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 it has a mulching option so you won't have to make lots of trips to the compost heap. We assess how easy to start each petrol mower is, from cold and after it's been run for a while. We also check it's got enough power to cut through long grass and tough, clumpy meadow grass.
Can I replace the battery?
Lithium-ion batteries always deplete and eventually die over time, and at Which?, we believe that cordless products should last longer than the batteries they come with. That's why we no longer give cordless lawn mowers Best Buys if spare batteries cannot be bought 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 achieve 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.