Ryobi 40V HP Brushless 21-inch Review

Introduction: Why I Finally Cut the Cord

For years, I was a gas mower loyalist. I loved the roar, the smell of fuel, and the feeling of raw power. But after my third carburetor rebuild in two seasons, I started eyeing the battery-powered world. The Ryobi 40V HP Brushless 21-inch mower kept popping up in my searches, mostly because of its price point. I’d seen the EGO and Toro models, but they were significantly more expensive. I needed a mower for my quarter-acre lot, and I wanted something that wouldn’t break the bank or require a chemistry degree to maintain. So, I bought the Ryobi, charged the batteries, and prepared to be either pleasantly surprised or bitterly disappointed.

This review is the result of three months of real-world testing on St. Augustine grass, Bermuda, and the occasional weed patch. I mowed wet grass, dry grass, tall grass, and short grass. I ran the battery down to zero more times than I care to admit. I’m not a lab technician, and I didn’t measure decibels with scientific equipment. I’m a YardToolLab editor who mows his own lawn and expects a tool to do its job without fuss. Here is the honest, unvarnished truth about the Ryobi 40V HP Brushless 21-inch mower.

How I Tested It: Real Lawns, Real Conditions

To get a fair assessment, I set up a structured testing regimen across three different properties. My primary test site is my own home, which has about 8,000 square feet of mixed turf. The front yard is mostly level with fine Bermuda, while the back is a bumpy mix of St. Augustine and clover. I also tested on a friend’s slightly larger lot (around 10,000 square feet) with thick, damp St. Augustine, and on a smaller, 4,000-square-foot rental property with neglected, overgrown grass.

I used the mower exclusively in its highest power mode (the “HP” setting) for all tests. I charged the included 6.0 Ah battery fully before each session and used a stopwatch to log runtime. I measured cut quality by visual inspection and by collecting clippings in a bag to check for uneven cutting or missed strips. I also ran the mower over a known hidden rock (a small landscaping stone) to test the blade impact system. Finally, I purposely let the grass grow to 6 inches in one section to see how the brushless motor handled thick, wet conditions.

Performance: The Good, the Bad, and the Battery

Cut Quality and Power

Let’s start with the most important part: how does it cut? In dry, normal-height grass (3 to 4 inches), the Ryobi 40V HP is excellent. The 21-inch steel blade (yes, it’s steel under the plastic deck) spins fast enough to slice through Bermuda like a hot knife through butter. The cut is clean, and the mulching capability is surprisingly good. I used the included mulching plug, and it left a fine, almost invisible layer of clippings that broke down within a day. No clumping, no windrows.

Where it struggles is with thick, wet, or tall grass. When I hit that 6-inch patch of St. Augustine after a rain, the mower bogged down noticeably. The brushless motor didn’t stall, but it slowed, and the cut quality suffered. I had to lift the front wheels slightly and take a second pass. This is not a mower for jungle-like conditions. If you let your lawn get out of control, you will be frustrated. For weekly or bi-weekly mowing, though, it’s completely adequate.

The self-propelled system is a rear-wheel drive design with a variable speed trigger. I found it responsive and easy to control. The top speed is brisk enough for a quick walk, and the slow speed is great for maneuvering around flower beds. The drive engages smoothly, and it does not jerk forward like some budget models. However, on steep slopes, the rear wheels can lose traction if the grass is wet. For flat or gently sloping lawns, it’s fine.

Battery Runtime: The Real Story

This is the area where the Ryobi both shines and disappoints. With the included 6.0 Ah battery, I consistently got between 45 and 50 minutes of runtime on my 8,000-square-foot lawn. That was enough to finish the entire property with about 10 percent battery remaining. On the larger, 10,000-square-foot lot with thick St. Augustine, I got exactly 38 minutes before the battery died, leaving about 20 percent of the lawn unfinished. That was frustrating.

Here’s the honest truth: the battery runtime is good for the price, but it is not as long-lasting as the EGO 56V system. I have tested EGO mowers with a 7.5 Ah battery, and they routinely run 60 to 70 minutes under similar loads. The Ryobi battery also seems to degrade faster under heavy load. When I pushed it through that tall, wet grass, the battery indicator dropped from three bars to one in just 10 minutes. In normal conditions, the battery drains more linearly.

If you have a lawn under 6,000 square feet, the included battery is likely perfect. For larger lawns, you will almost certainly need a second battery. Ryobi sells these separately, and they are not cheap. This is a major consideration.

Noise and Vibration

This is where the Ryobi absolutely crushes gas mowers. It is quiet. I measured the noise level with a phone app (not scientific, but indicative) at around 72 decibels at ear level. That is about the same as a vacuum cleaner. I could mow at 7 AM on a Saturday without waking my neighbors. The vibration is minimal, thanks to the brushless motor. After 45 minutes, my hands were not numb, and my arms were not tired. This is a huge quality-of-life improvement over any gas mower I’ve ever used.

Build and Value: Plastic Deck, Real Tradeoffs

The Deck: Plastic vs. Steel

The most common criticism of the Ryobi 40V HP is the plastic deck. Let me address this head-on. Yes, the deck is made of a high-impact composite plastic. It feels lighter and less rigid than the stamped steel decks on most gas mowers or the aluminum decks on premium battery models like the EGO. I have not had any cracking or warping issues, but I also don’t abuse my tools. I do worry about long-term durability. If you regularly hit rocks, tree roots, or concrete curbs, the plastic deck could crack. I have seen this happen on older Ryobi models in online forums.

However, the plastic deck has a major advantage: it does not rust. I live in a humid area, and my old gas mower’s steel deck eventually rusted through. The plastic deck on the Ryobi will never rust. It is also lighter, which makes the mower easier to push (even without self-propulsion) and easier to lift for storage. The tradeoff is a slightly “cheaper” feel when you tap it with your foot. It doesn’t have the solid thud of a steel deck. But for the price, I accept this compromise.

Assembly and Storage

Assembly took about 15 minutes. The handle folds down with a single lever, which is fantastic for storage. It stands upright on its rear bumper, taking up minimal garage space. The grass bag is a soft fabric bag with a rigid plastic top. It holds a decent amount of clippings, but it is not as large as the bags on some 21-inch gas mowers. I had to empty it about every 200 square feet when mulching thick grass. The bag is easy to remove and empty, though the fabric can get smelly if you leave clippings in it for a few days.

Value for Money

I cannot give you an exact price because prices fluctuate, but I can say that the Ryobi 40V HP is consistently one of the most affordable 21-inch battery mowers on the market. It is significantly cheaper than the EGO, Toro, and Greenworks Pro models. For the price, you get a brushless motor, a 6.0 Ah battery, a charger, and a self-propelled system. That is a lot of value. The build quality is not premium, but it is functional. If you are price-sensitive and do not need the absolute best battery runtime, this is a strong contender.

Who Should Buy It (And Who Should Skip It)

Buy it if:

• You have a lawn under 8,000 square feet and want to go cordless without spending a fortune.
• You value quiet operation and want to mow early or late without disturbing neighbors.
• You are already invested in the Ryobi 40V platform (trimmers, blowers, etc.) and want a mower that uses the same batteries.
• You prioritize ease of maintenance (no oil, no gas, no spark plugs) over rugged build quality.
• You mow weekly or bi-weekly and keep your grass at a moderate height.

Skip it if:

• You have a lawn larger than 10,000 square feet and cannot afford a second battery.
• You regularly mow thick, wet, or overgrown grass that requires heavy-duty power.
• You are tough on equipment and need a steel or aluminum deck that can withstand impacts.
• You demand the absolute best battery runtime, even if it costs significantly more (look at EGO).
• You want a premium feel with soft-grip handles and a heavy-duty bagging system.

My Verdict: The Best Budget Battery Mower, With Caveats

After three months of testing, I can say that the Ryobi 40V HP Brushless 21-inch mower is a very good tool for the right person. It is not a perfect mower. The plastic deck feels less sturdy than I would like, and the battery runtime, while good, is not class-leading. But the cut quality is excellent for normal conditions, the self-propelled system works well, and the quiet operation is a game-changer. I have not missed my gas mower once.

For the price, this mower delivers outstanding value. It is not built to survive a decade of abuse, but if you treat it reasonably, it will serve you well for several seasons. If you have a small to medium lawn and want to cut the cord without cutting your budget, this is the mower I recommend. If you need more power or longer runtime, you will need to spend more money on a premium model. But for most homeowners, the Ryobi 40V HP is more than enough.

Pros:

• Affordable price for a brushless, self-propelled system.
• Good battery runtime for lawns under 8,000 square feet.
• Quiet operation that allows early or late mowing.
• Easy to assemble and store.
• No maintenance beyond blade sharpening.

Cons:

• Battery not as long-lasting as EGO under heavy loads.
• Plastic deck feels less sturdy and may crack under abuse.
• Struggles with thick, wet, or tall grass.
• Grass bag is smaller than average.

Would I buy it again? Yes. For my lawn, it works. If my lawn were larger or more demanding, I would have saved up for an EGO. But for the price, the Ryobi 40V HP is the best value in battery mowers I have tested. It is a solid, honest tool that gets the job done without breaking the bank or your back.