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According to our latest survey results, the most common faults of grass trimmers vary from one model to the next – whether you own a corded electric, cordless or petrol one.

If your corded grass trimmer develops a fault, it's most likely to be the line feed malfunctioning, with 34% of people saying they had experienced this. For cordless models, 17% also said the line feed malfunctioned, but this was joint with the battery not holding its charge. For petrol trimmers, the most common fault was the engine failing to turn over.

Knowing which brands develop the most faults, and how quickly, is vital when buying a new grass trimmer. Our data is based on a survey conducted in January 2022. We gathered feedback from 3,227 Which? members and the general public to find out how many models remained fault-free in the first seven years of ownership. Brands with insufficient sample sizes were not included (a minimum of 30 respondents is required).

Our survey data takes into account the reported fault rates, the severity of these faults and the speed with which they occurred. In our latest analysis, we've looked at the performance of the biggest grass trimmer manufacturers – including Bosch, Black & Decker, Flymo and Stihl – and have calculated a customer score for each, so you know which brands to choose and which to avoid.

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Table notes: Test scores correct as of July 2022. The customer score is based on a survey of grass-trimmer owners combining how satisfied they are with a brand and whether they'd recommend it to a friend. Results from corded electric, cordless and petrol grass trimmers combined.

As the table shows, there's a big difference in both our best and worst Which? test scores and the customer scores from our latest survey.

By consulting our expert reviews before you buy, you can be sure that you're investing in a grass trimmer that's easy to use and effective at trimming all manner of grass and weeds quickly and efficiently.

The table below summarises our latest results. Brands are ranked by their customer score, which relates to whether their customers would recommend that brand. 

In the table below, only logged-in  members can view which brands developed the least faults, and which ones members are most satisfied with. If you're not yet a member, join Which?  to get instant access.

Table notes:  The data is based on a survey of 3,227 Which? members and the general public in January 2022 who bought their grass trimmer between 2015 and 2021. Fault-free percentage based on respondents not having experienced a fault in the first seven years of ownership.

Corded, cordless and petrol grass trimmers all operate quite differently, so it's not surprising they encounter different problems.

The line feed breaking is a common problem. This is an annoying rather than a devastating issue and can be fixed on the spot. Read our expert guide on how to avoid line-feed problems for more details.

Luckily, most of the top faults are also fixable, or at least won't result in the total breakdown of your trimmer.

Log in or join Which? to get instant access to our grass-trimmer brand verdicts.

Know which grass-trimmer brand you want? Use the links to go straight to our reviews and find your ideal model:

Which? has a wealth of information on the UK’s favourite garden-tool brands. Every two years, we ask Which? members and the general public to tell us about the garden products they own - from how likely they'd be to recommend a brand, to whether they experienced any faults with it. This year, 8,881 people told us about their products. We calculate a brand's customer score based on the results of our biennial survey.

Our product experience surveys, combined with our extensive lab tests, mean we can recommend the best grass trimmer you should buy.