A powerful lawn mower for medium-sized gardens.
A solidly built and hugely reliable mower for medium size gardens, the Ryobi RY18LMX40B has everything you’d expect from this brand and at this price. With space for two batteries on board, three cutting speeds, and seven cutting heights, it’s ideal for regularly shaped gardens. The only drawbacks are that it’s not quite so easy to get in and out of awkward corners, and you’re parting with lots of cash if you need batteries to go with the machine.
-
Robust and comfortable to use -
Three selectable cutting speeds -
Capacious 50 litre grass collection bag
-
Expensive once you add batteries and a charger -
A bit cumbersome when turning around -
Poor run time on a single battery
Key Features
-
Battery power
Runs on Ryobi’s 18V batteries, with space for two for extra power and cutting time. -
Cutting height
Adjustable between 25mm and 75mm.
Introduction
Running on Ryobi’s tried and true 18 Volt battery system, the Ryobi 18V ONE+ HP Cordless Brushless 40cm Lawnmower RY18LMX40B is a mower designed for medium to large-sized gardens. Cutting a 40 cm swathe, it can cover a large area in no time.
If you’ve got Ryobi batteries already, this is a good add-on; if you don’t, it’s expensive to buy with batteries and chargers and battery life from one battery isn’t very good.
Design and Features
- Selectable mowing speeds
- Battery charge indicator on the handle
- Folds down small for storage
The large, chunky components on this mower feel robust and ready for work. Unfolding the handle and selecting the two different handle lengths is easy, with large green catches that show up well on the mower’s grey body. There are two handle heights as well, and even a way to slightly adjust the angle of the handle to accommodate different height users.
Priced at £388.99 without batteries, this is by no means a cheap lawnmower. If you already have decent capacity Ryobi batteries from 4.0Ah upwards, it’s not too bad, but if you factor in buying new ones, it gets expensive.
As well as folding down, the lawn mower can also be stood upright for storage, so it doesn’t take up much space in a shed.
Weighing just over 18 kg, this is a lighter mower than the Stihl RMA 248.3 by a long way. This is probably due to the use of plastics over steel for the cutting deck. It doesn’t feel like a flimsy piece of kit though. The tough polymer plastic is a great way to reduce weight while still offering plenty of protection.
There are seven cutting heights to choose from, selected with a big chunky handle, from 25 – 75 mm. To tackle tough terrain, there are big plastic wheels on each corner. Measuring 20 cm on the back and 15 cm on the front, it’s easy to push over small bumps and kerbs.
Featuring a 50-litre metal framed fabric grass collection bag, it has a handy indicator that tells you when to empty the clippings. If you don’t feel like dealing with cuttings, the mower comes with a mulching plug installed. There’s no side discharge mode though.
This feels like a modern and intelligent mower. The handle features a small LED control panel that lets you choose mowing speeds and shows the battery charge level, a bit like the DeWalt DCMWP134. The three modes are “eco”, a slower speed to conserve battery life, “power” mode to slash through thick grass at maximum revolutions, and “intelligent” mode that chooses a blade speed depending on the resistance that the blade is under. It works.
The small readout also lets you know if there are any errors with the motor or if the blades are becoming dull and need to be resharpened.
Making everything work is a brushless motor, and the power comes from Ryobi’s excellent ONE+ battery system. Compatible with hundreds of tools, they’re a good investment if you haven’t already bought into a battery ecosystem. Running at around 96dB, it’s not a quiet mower, but certainly makes less noise compared with a petrol version.
The mower will run on a single battery, but to increase the runtime, there’s space for two 18 Volt batteries side by side. They sit in a clear plastic housing containing a very handy safety key. Once the key is removed, curious children or other undesirables cannot start the mower.
Performance
- Plenty of power for long grass
- Decent battery life
- Enough grass collection capacity
To thoroughly test out this mower, I tackled a 250m² lawn that featured odd corners, some steep sections and plenty of undulations. There was no assembly required other than taking it out of the box and plugging in the batteries.
After cutting the lawn the first time, the pair of 4.0Ah batteries were left with about 25% battery power each. That’s not bad for around 30 minutes of mowing, especially as the grass was quite long in places. Subsequent lawn mowing sessions used a similar amount of battery life.
It wouldn’t have lasted with a single battery on board though. Although you could run the mower with just one, it would probably give you less than 20 minutes of run time, especially on high power mode.
Even though the weight of this mower was kept down by the judicious use of tough plastics, it still didn’t feel quite as well balanced as the Stihl RMA 248.3. The long overall length of the mower makes it harder to turn around at the end of the lawn in comparison.
The bright LED readout makes it easy to check the battery life as you get on with the mowing, a quick press of the button and it lights up bright green, which is easy to see even in direct sunlight. It works a little better than the white lights on the DeWalt DCMWP134
Ryobi has had plenty of experience making lawn care products, so it was no surprise to me that the RY18LMX40B left a great quality cut.
Should you buy it?
You should buy this mower if you already have Ryobi batterie
It’s a capable mower that has a comfortable handle and useful battery level indicator readout.
You should not buy this mower if you need to buy a whole set of new batteries
It’s expensive once you factor in buying new batteries.
Final Thoughts
The Ryobi 18V ONE+ HP Cordless Brushless 40cm Lawnmower RY18LMX40B is great for anyone who already has Ryobi batteries in their arsenal. A big and chunky mower, it’s well built and quite comfortable to use over long mowing sessions. It is expensive if you don’t have Ryobi batteries already, so you may prefer a different model from our list of the best lawn mowers.
How we test
We test every lawn mower we review thoroughly over an extended period of time. We use standard tests to compare features properly. We’ll always tell you what we find. We never, ever, accept money to review a product. Find out more about how we test in our ethics policy.
- Used as our main lawn mower for the review period
- Used on a variety of grass lengths to see how well the mower cuts
- Tested to see how easy the mower is to push, turn and store
FAQs
With two batteries you get more run time and a power boost.
Yes, the handle folds down and you can stand the lawn mower up.
Test Data
| Ryobi 18V ONE+ HP Cordless Brushless 40cm Lawnmower RY18LMX40B |
|---|
Full Specs
| Ryobi 18V ONE+ HP Cordless Brushless 40cm Lawnmower RY18LMX40B Review | |
|---|---|
| Manufacturer | – |
| Weight | 18.62 KG |
| Release Date | 2025 |
| First Reviewed Date | 19/05/2025 |
| Model Number | RY18LMX40B |
| Lawn Mower Type | Cordless |
| Adjustable height | No |
| Blade Type | Steel blade |
| Cutting width | 40 cm |
| Grass catcher box size | 50 litres |
A powerful lawn mower for medium-sized gardens.
A solidly built and hugely reliable mower for medium size gardens, the Ryobi RY18LMX40B has everything you’d expect from this brand and at this price. With space for two batteries on board, three cutting speeds, and seven cutting heights, it’s ideal for regularly shaped gardens. The only drawbacks are that it’s not quite so easy to get in and out of awkward corners, and you’re parting with lots of cash if you need batteries to go with the machine.
-
Robust and comfortable to use -
Three selectable cutting speeds -
Capacious 50 litre grass collection bag
-
Expensive once you add batteries and a charger -
A bit cumbersome when turning around -
Poor run time on a single battery
Key Features
-
Battery power
Runs on Ryobi’s 18V batteries, with space for two for extra power and cutting time. -
Cutting height
Adjustable between 25mm and 75mm.
Introduction
Running on Ryobi’s tried and true 18 Volt battery system, the Ryobi 18V ONE+ HP Cordless Brushless 40cm Lawnmower RY18LMX40B is a mower designed for medium to large-sized gardens. Cutting a 40 cm swathe, it can cover a large area in no time.
If you’ve got Ryobi batteries already, this is a good add-on; if you don’t, it’s expensive to buy with batteries and chargers and battery life from one battery isn’t very good.
Design and Features
- Selectable mowing speeds
- Battery charge indicator on the handle
- Folds down small for storage
The large, chunky components on this mower feel robust and ready for work. Unfolding the handle and selecting the two different handle lengths is easy, with large green catches that show up well on the mower’s grey body. There are two handle heights as well, and even a way to slightly adjust the angle of the handle to accommodate different height users.
Priced at £388.99 without batteries, this is by no means a cheap lawnmower. If you already have decent capacity Ryobi batteries from 4.0Ah upwards, it’s not too bad, but if you factor in buying new ones, it gets expensive.
As well as folding down, the lawn mower can also be stood upright for storage, so it doesn’t take up much space in a shed.
Weighing just over 18 kg, this is a lighter mower than the Stihl RMA 248.3 by a long way. This is probably due to the use of plastics over steel for the cutting deck. It doesn’t feel like a flimsy piece of kit though. The tough polymer plastic is a great way to reduce weight while still offering plenty of protection.
There are seven cutting heights to choose from, selected with a big chunky handle, from 25 – 75 mm. To tackle tough terrain, there are big plastic wheels on each corner. Measuring 20 cm on the back and 15 cm on the front, it’s easy to push over small bumps and kerbs.
Featuring a 50-litre metal framed fabric grass collection bag, it has a handy indicator that tells you when to empty the clippings. If you don’t feel like dealing with cuttings, the mower comes with a mulching plug installed. There’s no side discharge mode though.
This feels like a modern and intelligent mower. The handle features a small LED control panel that lets you choose mowing speeds and shows the battery charge level, a bit like the DeWalt DCMWP134. The three modes are “eco”, a slower speed to conserve battery life, “power” mode to slash through thick grass at maximum revolutions, and “intelligent” mode that chooses a blade speed depending on the resistance that the blade is under. It works.
The small readout also lets you know if there are any errors with the motor or if the blades are becoming dull and need to be resharpened.
Making everything work is a brushless motor, and the power comes from Ryobi’s excellent ONE+ battery system. Compatible with hundreds of tools, they’re a good investment if you haven’t already bought into a battery ecosystem. Running at around 96dB, it’s not a quiet mower, but certainly makes less noise compared with a petrol version.
The mower will run on a single battery, but to increase the runtime, there’s space for two 18 Volt batteries side by side. They sit in a clear plastic housing containing a very handy safety key. Once the key is removed, curious children or other undesirables cannot start the mower.
Performance
- Plenty of power for long grass
- Decent battery life
- Enough grass collection capacity
To thoroughly test out this mower, I tackled a 250m² lawn that featured odd corners, some steep sections and plenty of undulations. There was no assembly required other than taking it out of the box and plugging in the batteries.
After cutting the lawn the first time, the pair of 4.0Ah batteries were left with about 25% battery power each. That’s not bad for around 30 minutes of mowing, especially as the grass was quite long in places. Subsequent lawn mowing sessions used a similar amount of battery life.
It wouldn’t have lasted with a single battery on board though. Although you could run the mower with just one, it would probably give you less than 20 minutes of run time, especially on high power mode.
Even though the weight of this mower was kept down by the judicious use of tough plastics, it still didn’t feel quite as well balanced as the Stihl RMA 248.3. The long overall length of the mower makes it harder to turn around at the end of the lawn in comparison.
The bright LED readout makes it easy to check the battery life as you get on with the mowing, a quick press of the button and it lights up bright green, which is easy to see even in direct sunlight. It works a little better than the white lights on the DeWalt DCMWP134
Ryobi has had plenty of experience making lawn care products, so it was no surprise to me that the RY18LMX40B left a great quality cut.
Should you buy it?
You should buy this mower if you already have Ryobi batterie
It’s a capable mower that has a comfortable handle and useful battery level indicator readout.
You should not buy this mower if you need to buy a whole set of new batteries
It’s expensive once you factor in buying new batteries.
Final Thoughts
The Ryobi 18V ONE+ HP Cordless Brushless 40cm Lawnmower RY18LMX40B is great for anyone who already has Ryobi batteries in their arsenal. A big and chunky mower, it’s well built and quite comfortable to use over long mowing sessions. It is expensive if you don’t have Ryobi batteries already, so you may prefer a different model from our list of the best lawn mowers.
How we test
We test every lawn mower we review thoroughly over an extended period of time. We use standard tests to compare features properly. We’ll always tell you what we find. We never, ever, accept money to review a product. Find out more about how we test in our ethics policy.
- Used as our main lawn mower for the review period
- Used on a variety of grass lengths to see how well the mower cuts
- Tested to see how easy the mower is to push, turn and store
FAQs
With two batteries you get more run time and a power boost.
Yes, the handle folds down and you can stand the lawn mower up.
Test Data
| Ryobi 18V ONE+ HP Cordless Brushless 40cm Lawnmower RY18LMX40B |
|---|
Full Specs
| Ryobi 18V ONE+ HP Cordless Brushless 40cm Lawnmower RY18LMX40B Review | |
|---|---|
| Manufacturer | – |
| Weight | 18.62 KG |
| Release Date | 2025 |
| First Reviewed Date | 19/05/2025 |
| Model Number | RY18LMX40B |
| Lawn Mower Type | Cordless |
| Adjustable height | No |
| Blade Type | Steel blade |
| Cutting width | 40 cm |
| Grass catcher box size | 50 litres |
