Roborock RockMow X120H

The largest lawn the manufacturer rates the mower for, in square feet. As a reference, a quarter acre is about 10,900 sq ft and a full acre is about 43,560 sq ft.

The figure assumes the mower can run several sessions per week. Buying a model rated close to your actual lawn size leaves no margin for a rainy week, so it is common to pick one size class above your lawn.

Manufacturers measure only mowable grass, not the total plot: driveways, beds, pools and the house itself do not count.

The steepest gradient the mower can climb, expressed as a percentage. A 45% slope rises 45 cm over 1 metre of travel, which is roughly 24 degrees.

Entry-level models stop around 30%, mid-range two-wheel-drive units reach 45% to 50%, and all-wheel-drive models go up to 80% or more.

Slope ratings assume dry grass. Wet or thatchy lawns cut the usable figure, so leave some headroom over the steepest part of your garden.

How many wheels the mower drives: front-wheel drive (FWD), rear-wheel drive (RWD, also sold as 2WD) or all-wheel drive (AWD, also sold as 4WD).

Two-wheel-drive mowers are lighter, cheaper and fine on flat and gently rolling lawns. All-wheel drive adds traction for steep banks, wet grass, ruts and thick thatch, at a clear price premium.

The tallest step, root or paving edge the mower can drive over without getting stuck.

Gardens split into zones by a path or a low kerb need a mower that can cross it on its own, otherwise you have to carry the mower between zones or set up a separate map for each one.

The positioning technology the mower uses to know where it is and where the lawn ends.

- Perimeter wire: a cable pegged around the lawn defines the boundary. Cheap and reliable, but installation takes a day and changes to the garden mean re-laying cable.

- RTK: a satellite antenna, usually on a separate mast, corrects GPS down to a couple of centimetres. Needs a clear view of the sky and struggles under dense trees.

- Vision: cameras read the grass and the surroundings, so no antenna is needed, but heavy shade, glare and dusk can confuse it.

- LiDAR: a spinning laser maps the garden in 3D and works in shade and at night. It is the most expensive option and the one most models launched in 2025 and 2026 use.

Most current mowers combine two or three of these, using one as a fallback for the other.

Whether the mower works without a buried or pegged boundary cable around the lawn.

Wire-free mowers are set up by walking the mower around the garden once, or by letting it map on its own, and the boundary can be redrawn in the app whenever the garden changes. Wired models need the cable installed once and repaired whenever it is cut by an aerator or a spade.

RTK (Real-Time Kinematic) corrects satellite positioning with a fixed reference station, bringing accuracy from several metres down to about 2 cm.

It gives the straight, overlapping mowing lines these mowers are known for, but the reference antenna needs an open view of the sky and a power supply, and signal drops under trees or next to tall buildings. Some models replace the local antenna with a network RTK service delivered over 4G.

A laser scanner that measures distances around the mower and builds a 3D map of the garden.

LiDAR does not depend on satellites or daylight, so it keeps working under trees, along fences and after dark, which is exactly where RTK and camera-only mowers lose position. It is the main reason premium models cost what they do.

A camera plus object recognition that identifies what is in front of the mower, instead of only bumping into it and turning away.

This is what keeps the mower from running over hoses, toys, fallen fruit, pet waste and sleeping hedgehogs. Models without it rely on a bumper and will push small objects around the lawn.

Support for splitting the garden into separate zones that can be mowed on their own schedule, height or order.

Useful when the front and back lawn grow at different rates, or when one area is used for play at the weekend and should be cut on weekdays only.

Virtual areas drawn in the app that the mower will not enter, such as flower beds, a pond, a vegetable patch or a trampoline.

On wire-free mowers this replaces the second loop of boundary cable that wired models need around every obstacle.

The width of grass the mower cuts in a single pass, in inches.

A wider deck covers the lawn in fewer passes, so the mower finishes sooner and runs fewer sessions per week. Narrow decks, around 8 to 9 inches, are easier to steer through tight gardens; large models reach 17 inches.

The range of grass heights the mower can be set to, from the lowest to the highest setting.

Fine ornamental lawns are cut around 1 to 1.5 inches, while shaded lawns, drought-prone lawns and most warm-season grasses are healthier at 3 inches or more. Check that the range your lawn needs is actually inside the mower's range.

How the cutting height is changed: by hand with a dial on the mower, or electronically from the app.

App-controlled height lets you drop the cut for a garden party and raise it for a dry spell without walking to the mower, and it allows a different height per zone.

The ability to cut right up to a wall, fence or bed, either with a blade disc that reaches past the wheels or with a dedicated side trimmer arm.

Without it, a strip of a few centimetres is left standing along every border and you finish the job by hand with a string trimmer, which is the most common complaint about robot mowers.

The cutting hardware itself: small pivoting razor blades on a spinning disc, a single rotary blade like a traditional mower, or two blade discs side by side.

Pivoting blades are cheap to replace and fold away on impact, which is safer, but they need frequent changes and cope badly with tall or wet grass. Rotary and dual-disc systems cut heavier growth and leave a cleaner finish.

How much lawn the mower covers per hour, in square metres, as rated by the manufacturer.

It combines cutting width, driving speed and how systematic the mowing pattern is, so it is the best single number for how long a session takes. Figures range from about 120 m²/h on small vision models to 500 m²/h and more on large systematic ones.

The size of the mower's battery pack, usually given in amp-hours (Ah) or milliamp-hours (mAh).

Capacity alone does not decide runtime, because motors and voltage differ between models, but within a brand a larger pack means longer sessions and fewer charging breaks on a big lawn.

How long the mower cuts on a single charge before returning to the station.

Runtimes between 60 and 220 minutes are typical. A short runtime is not a problem in itself, because the mower recharges and resumes on its own, but it stretches a large lawn over more hours and more of the day.

Time required to fully recharge the battery at the station.

Together with battery life it sets how much lawn the mower gets through in a day: a model that cuts for 90 minutes and charges in 50 works far more than one that cuts for 90 and charges for 180.

Whether the battery pack can be removed and replaced by the owner without opening the mower.

A swappable pack lets you keep a charged spare for large lawns and, more importantly, means a worn battery after a few seasons is a cheap part rather than the end of the mower.

Range: The 2.4 GHz band offers a longer range, meaning it can cover larger areas and penetrate solid objects like walls more effectively than 5 GHz.

Speed: Generally, 2.4 GHz provides slower speeds compared to 5 GHz due to a lower maximum data rate.

Interference: More prone to interference since many other devices (like cordless phones, microwaves, and Bluetooth devices) operate on the 2.4 GHz frequency, leading to potential congestion and slower network performance.

For a robot mower, the relevant question is whether your home WiFi actually reaches the far end of the garden, which is where the mower and its station sit.

Range: Offers a shorter range compared to 2.4 GHz and may have difficulty penetrating walls and other obstacles.

Speed: Typically provides faster speeds and higher data rates due to more available bandwidth.

Interference: Less prone to interference as fewer devices operate on this frequency, leading to a more stable connection.

Bluetooth is a wireless communication technology used for exchanging data over short distances.

On a robot mower, Bluetooth is mainly used for the initial setup and as a local fallback: when the garden is out of WiFi range, you can still start, stop and steer the mower while standing next to it.

A built-in mobile data module, sometimes with a bundled data plan for the first years.

Cellular connectivity keeps the mower reachable in gardens where WiFi does not reach, delivers network RTK corrections without a local antenna, and is what makes GPS theft tracking work once the mower leaves your property.

Additional connectivity options not covered by the standard protocols.

This may include proprietary radio links between the mower and its RTK antenna, LoRa-style long-range links, or other specialized communication methods.

Google Home serves as a central hub for a variety of smart devices, including lights, thermostats, cameras, and speakers. It leverages Google Assistant for voice control, enabling users to manage their smart home with simple commands.

Amazon Alexa is one of the most widely used smart home systems, known for its compatibility with a vast array of devices. Users can control everything from smart lights to appliances using voice commands through Echo devices.

Apple HomeKit is designed for users in the Apple ecosystem, providing a seamless way to control compatible smart devices through iOS devices using the Home app or Siri. It emphasizes security and user privacy.

SmartThings is a flexible platform that connects a wide range of devices from different brands, offering a unified interface for control. It supports various communication protocols, allowing for extensive device compatibility.

Home Assistant is an open-source platform that allows for extensive customization and integration of a wide variety of smart devices. It supports a multitude of protocols and brands, making it ideal for tech-savvy users.

Robot mower support in Home Assistant ranges from an official integration to community add-ons that talk to the manufacturer's cloud, so it is worth checking which of the two a brand offers.

Matter is a unified, open-source connectivity protocol designed to standardize and simplify communication between smart home devices from different manufacturers. Developed by the Connectivity Standards Alliance (formerly the Zigbee Alliance), Matter aims to improve interoperability, security, and reliability across various smart home ecosystems.

Matter operates over existing networking technologies, including Ethernet, Wi-Fi, and Thread, providing flexibility in device connectivity. Its IP-based nature allows seamless integration with existing internet infrastructure and cloud services.

Robot mowers are a late arrival to Matter: the specification only added an appliance-style device type for them recently, so most models on sale still integrate through their own cloud instead.

A sensor that detects rain and sends the mower back to its station, resuming when the lawn is dry.

Cutting wet grass tears the blades, clogs the deck and leaves ruts on soft ground, so this protects the lawn as much as the mower. Some models replace the physical sensor with an online weather forecast.

Sensors that stop the blades within a fraction of a second when the mower is lifted off the ground or tipped over.

This is the core safety mechanism of any robot mower and the reason it can run around children and pets. It is close to universal, but the reaction time and whether the mower also stops on a steep tilt differ between models.

Recognition of people and animals as a distinct category of obstacle, so the mower slows down, stops or drives around them instead of nudging them.

Only mowers with a camera or LiDAR can do this. Bumper-only models detect a child or a pet the same way they detect a fence post: by touching it first.

A physical stop button on the mower that immediately halts the blades and the drive motors.

Regulations in several markets require one, and it is the fastest way to stop the machine when something goes wrong within arm's reach.

The mower reports its own position, so you can locate it on a map if it is taken from the garden.

A robot mower is a four-figure machine that sits unattended in an open garden, which makes it a target. Tracking is most useful when the mower also has its own cellular connection, because a stolen mower is quickly out of WiFi range.

A numeric code required on the mower's keypad or in the app before it will operate.

It makes a stolen mower useless to the thief and stops unauthorized starts, for example by a curious child.

An audible alarm that sounds when the mower is lifted or moved outside its mapped garden.

It is a deterrent rather than a lock, but it works even when the mower has no data connection, and it is usually paired with a push notification to your phone.

Setting the days and hours the mower is allowed to work, so it stays in its station while the garden is in use or during quiet hours.

Every mower schedules by day and time slot; what differs is whether each zone can carry its own schedule.

The mower adjusts how often it cuts based on grass growth, the local forecast or the season, instead of following a fixed calendar.

In practice this means fewer sessions during a dry August and more during a wet spring, which saves battery cycles and keeps the mower off the lawn when the grass is soaked.

A live view of the mower's position on the garden map while it works.

It is the quickest way to find the mower when it stops with an error somewhere behind the hedge, and it shows which parts of the lawn have already been cut.

Driving the mower from the phone app like a remote-controlled vehicle.

Used for spot mowing a patch that grew too tall, for recovering the mower from a corner it got stuck in, and for walking the boundary during setup.

LED lights on the front of the mower.

They let camera-based models keep recognizing obstacles after dark, which matters because night mowing is the main way to keep the machine out of the way, and they make the mower easier to spot in the garden.

The ability to trigger the mower from other events in the smart home, or to have the mower trigger other devices.

Typical examples are pausing the mow when the irrigation system starts, or having outdoor lights turn on when a night session begins.

It keeps working, and can be controlled from inside your own network, when the internet is down: over Zigbee, Z-Wave or Thread through a local hub, a native Matter or HomeKit connection, a documented local API or an official local integration.

A product without local control stops answering during an internet outage and depends on the maker's servers staying online.

Every advertised feature works without a paid plan: app control, alerts, history and the smart home integrations.

Some products put video history, monitoring or their integrations behind a monthly plan that can cost more per year than the hardware did.