Ryobi 40V HP Brushless 21 inch Review

Why I Picked This Mower for My Own Yard

I have been cutting grass for a living and for fun for over a decade. When I stepped away from the landscape crew to run my own tests at YardToolLab, I knew exactly what I wanted in a cordless mower for my half acre and the neighbors’ patches I still help with. I needed something that would not break the bank, that would let me use the same batteries as my Ryobi trimmer and blower, and that would not wake up my kid’s afternoon nap. That is why I landed on the Ryobi 40V HP Brushless 21 inch self propelled mower. It is our “Best Value” pick for a reason. I have put it through three full mowing seasons now, on wet grass, dry grass, thick Bermuda, and even some rogue crabgrass patches that would choke a lesser machine. Here is the honest truth from my own lawn.

How I Tested It

I do not test mowers on a perfect golf course. I test them on my own bumpy half acre that slopes toward the street, has a few oak roots I have not ground down yet, and gets a mix of sun and shade. I also mow for two neighbors: one with a flat, manicured fescue lawn and another who lets his St. Augustine get shaggy between cuts. Over the last year, I have used this Ryobi for at least forty mows, sometimes back to back on the same day. I always start with a full charge on the included 6Ah battery, and I keep a stopwatch on my phone to track runtime. I check how clean the cut is by looking at the clippings on the driveway after a pass. I also pay attention to how the self propel feels on an incline, because my yard has a decent grade near the back fence.

I want to be clear: I am not a lab coat guy. I am a guy who has loaded mowers onto a trailer at 6 AM and who knows the difference between a mower that works and one that fights you. This Ryobi has been a solid worker, but it has its limits. I will tell you about both.

Cutting Power

The 40V HP brushless motor is the star here. It spins the blade fast enough to slice through my thick Bermuda without bogging down, even when I let the grass get a little tall. I had a stretch last June where rain kept me off the lawn for ten days. When I finally got out there, the grass was pushing six inches in spots. I put the Ryobi on the highest cutting height, took a conservative first pass, and it chewed through without stalling. The motor did not whine or struggle. It just kept a steady hum. That impressed me because I have used cheaper cordless mowers that would quit on that kind of growth.

One thing I noticed right away is the 21 inch deck does a good job of keeping the clippings spread evenly. I do not get those clumps of wet grass that plug up the chute on other mowers I have tested. The blade is sharp out of the box, and after a season of use, I still get a clean slice on the grass blades. If you look at the lawn after a cut, you see clean tips, not ragged tears. That matters for lawn health and for looks. The only time I saw the motor struggle was when I hit a thick patch of wet leaves in the fall. The leaves matted together and the mower slowed down, but it did not stall. I just lifted the front wheels a little and it cleared out.

I also like that this mower has a brushless motor that runs cool. After a full 45 minute mow on a hot July afternoon, the motor housing was warm but not hot. That tells me the efficiency is real. It is not wasting energy as heat, which means more power goes to the blade and less to cooking the electronics.

Battery and Runtime

Let me be straight with you: the battery runtime is the biggest trade off on this mower. With the included 40V 6Ah battery, I get about 35 to 45 minutes of real world mowing. That is with the self propel engaged most of the time and the blade running at full speed. On my half acre, that is usually enough to finish the whole yard if I am efficient. But if the grass is thick and wet, or if I have to go over some spots twice, I run out of juice with about twenty feet of lawn left. That happened twice last summer. I had to wait for the battery to charge, which takes about an hour and a half, to finish that last strip. It is frustrating.

Compared to premium models that run 60 to 70 minutes on a single charge, this is a clear step down. But here is the thing: those premium mowers cost a lot more. And because this mower is compatible with the Ryobi 40V battery range, I already had two other 4Ah batteries from my trimmer and blower. So I just swap in a fresh battery when the 6Ah dies. That solves the runtime issue for me. If you are buying this as your first Ryobi tool, I recommend picking up at least one extra 4Ah or 6Ah battery. It makes the mower much more practical for a half acre or larger.

I also tested the battery life on my neighbor’s flat fescue lawn. That grass is thinner and shorter, and I got a full 45 minutes of mowing with battery to spare. So your mileage really depends on grass density and how much you use the self propel. On light duty, you might get closer to 50 minutes. On heavy duty, expect 35.

Handling and Build

The self propelled drive is a variable speed system. You squeeze a bar on the handle to engage it, and you can adjust the speed with a dial. I found the slowest speed perfect for thick grass where I need to take my time, and the fastest speed works well on flat, thin lawns. On my sloped yard, the drive does a decent job pulling the mower uphill. It is not as strong as a premium Toro or Honda self propel, but it gets the job done. I never felt like I was fighting the mower on the incline. The front wheels are 7 inches and the rear are 10 inches, which helps with rolling over bumps and roots. I did have to lift the front wheels over a thick oak root once or twice, but that is normal for any mower on my yard.

Now, the plastic deck. I have to be honest here: the deck feels less durable than a steel or aluminum deck. It is a thick, reinforced plastic, and it has not cracked or warped on me yet. But I can feel the flex if I push down on the deck while changing the cutting height. The cutting height adjustment is a single lever that moves all four wheels at once, which is convenient. But the lever itself is plastic and I worry about it breaking if I am rough with it. For a homeowner who takes care of their mower, it is fine. For a commercial crew using it every day, I would not trust it.

The handle folds down for storage, which is nice for my small shed. The handle itself is padded and feels comfortable. The controls are simple: a safety key, a start button, and a bail bar. No confusing touch screens or apps. That is how I like it. The mulching plug works well, and the side discharge chute is easy to install. I mostly mulch, but I use the side discharge when the grass is really tall to avoid clogging.

One small annoyance: the grass catcher bag is a little small. It fills up fast on thick grass, and you have to empty it often. That is common with cordless mowers because the bag is designed to be lightweight. But it is something to know if you hate stopping to empty the bag.

Who Should Buy It

This mower is for the homeowner who wants a quiet, affordable, battery powered mower that works with their existing Ryobi tools. If you already have a Ryobi 40V trimmer, blower, or chainsaw, this is a no brainer. You can share batteries and save money. It is also great for people with small to medium lawns, up to about a third of an acre on a single charge, or up to half an acre if you have a spare battery. The quiet motor means you can mow early on a Saturday without waking the neighbors. I have mowed at 7 AM and nobody complained.

It is not for someone with a large lawn over half an acre, unless you are willing to buy multiple batteries and swap them. It is also not for someone who needs a rugged, commercial grade deck that can take abuse. If you plan to mow for a living or you have a yard full of rocks and stumps, get a steel deck mower. But for the average homeowner who wants a good value, this is the mower I recommend most often.

My Verdict

After a full season of real world testing on my own lawn and my neighbors’ lawns, I can say the Ryobi 40V HP Brushless 21 inch self propelled mower earns its spot as our Best Value pick. It cuts well, it is quiet, and it uses the same batteries as the rest of my Ryobi tools. The brushless motor gives it plenty of power for most grass types, and the self propel makes mowing my sloped yard much easier than pushing a heavy gas mower.

Yes, the battery runtime is shorter than premium models, and the plastic deck does not feel as tough as metal. But for the price, which is very affordable compared to the high end competition, you get a reliable mower that does the job. I have not had a single mechanical issue. No belt snapped, no blade seized, no battery failed. It just works. If you are looking for a cordless mower that balances cost, performance, and convenience, this is the one I would buy again for my own yard.