Greenworks 40V 21" Review

Brushless Cordless Self-Propelled Lawn Mower with 5.0Ah Battery and Charger


Final Score

4.3 / 5 from 937 users

Greenworks 40V 21" | Tools Official
Greenworks 40V 21" | Tools Official
Greenworks 40V 21" | Tools Official


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We spent 9.4 hours reading reviews from customers and experts. In summary, here's what users think:

12 reasons to buy

  • The Greenworks 40V 21" lawn mower has received notable reviews for its self-propelled feature, which includes a throttle lever that allows users to adjust the speed from slow to fast, greatly simplifying the mowing process, particularly on hilly terrain. (33 reviews)

    • “This self propelled mower solves both those problems it is a dream to mow with.”

    • “With the self propelled function, yes it goes thru the battery faster, but heres the key: IT MOWES FASTER THAN A GAS POWERED MOWER twice its size.”

    • “It has a variable speed self propel feature.”

    • “The self-propelled function is very powerful”

    • “The self propelling drive, with a large rear wheel, actually propelled this mower up the hill will 10% the effort.”

    • “Plenty of power, and the self-propelled feature really lightens the workload.”

    • “The mowers drive system is strong and easily adjustable right on the handle.”

    • “The self-propelled feature has an adjustable speed, something that is great for this elderly man with bad knees.”

    • “Cut my 1/2 acre yard today on one battery charge using the self propelled feature.”

    • “Self propelled so easy to maneuver.”

  • The mower is described as easy to assemble, often requiring no tools and just attaching the handle before it's ready to use. (20 reviews)

    • “It's also a snap to assemble, no tools needed, just attach the handle and charge the battery and you're ready to go.”

    • “It was easy to assemble and well packed.”

    • “Assembly was easy.”

    • “I think it took me all of maybe ten minutes to unbox and assemble.”

    • “Very easy to assemble.”

    • “I was able to put the mower together by myself without any issues in less than 30 mins.”

    • “The mower arrived and took me a few minutes to assemble.”

    • “It was easy to put together”

    • “That said the assembly only took a few minutes.”

    • “Set up was super easy.”

  • The power of the mower is adequate for ordinary mowing tasks and is compared favorably to gas mowers in terms of efficiency and the ability to mow faster in some cases. (19 reviews)

    • “I would not call the mower under powered.”

    • “Lots of power”

    • “it has worked better than I would have imagined”

    • “This mower is better than most of the gas-powered mowers I've had in the past. Plenty of power,”

    • “the mower cuts as well as my gas mower”

    • “Power is great.”

    • “It’s no gas mower but it has gotten the job done!”

    • “Pretty powerful for an electric motor”

    • “So much power and works really well.”

  • Being battery-powered, the mower doesn't require gas and doesn't emit exhaust, which is appreciated by users. (10 reviews)

    • “Whisper quiet, no gas, no exhaust, I absolutely love it and highly recommend to anyone.”

    • “I had been using a name brand self-propelled, mulching gas mower and was getting sick of dealing with gas, oil, air filters, expensive tuneups, noise, and vibrations. This battery powered mower has relieved all of that”

    • “Not having to fill with gas each use and then pull a cord 20 times to get it to start is the best about this electric lawnmower.”

    • “No gas. Charge the battery and go!”

    • “The mower is extremely easy to start and doesn't use gas, two positive features.”

    • “it's safer to operate compared to a gas propelled lawn mower.”

    • “I never have to buy gas and I won’t have to winterize it in the fall”

    • “It was so nice not to have to worry about gasoline and whether the gas mower would even start after sitting for several months.”

    • “Battery operated take away all the clean up of gas powered mowers.”

    • “saves on gas and oil”

  • The Greenworks 40V 21" lawn mower starts easily, offering a significant convenience over the traditional pull-start mechanisms found in many gas mowers. (9 reviews)

    • “just attach the handle and charge the battery and you're ready to go.”

    • “like the ease of starting”

    • “So, I bought this mower simply for the push button start.”

    • “Once you have inserted the battery and plugged in the key it's as easy as pushing a button and pulling the rotor bar back.”

    • “The mower is extremely easy to start”

    • “Easy to start and operate!!”

    • “Starting the mower even easier. Just a push button.”

    • “love pushbutton start”

    • “Super easy to start and use.”

  • The mower is noted for being whisper-quiet compared to gas mowers, making for a more pleasant mowing experience. (8 reviews)

  • The mower is described as being easier to clean compared to gas mowers, likely due to the lack of oil and gas spill concerns. (5 reviews)

    • “It is also far easier to clean the underside since you do not have to worry about gas and oil leaking out”

    • “Deck and blades are perfectly clean.”

    • “Underneath easy to clean.”

    • “easy to clean”

    • “allows for easy under deck cleaning since tipping doesn't spill any fluids”

  • The mower is capable of folding up for vertical storage, making it a space-saving solution in storage areas like garages or sheds. (5 reviews)

    • “and the fact that it folds up and stores vertically is a huge help in our cramped garage”

    • “The standing storage feature is a blessing, takes very little room to store”

    • “I love that it can be folded for storage. It really opened up my storage shed.”

    • “Easy fold ip makes for ideal storage.”

    • “Can be stored upright”

  • The Greenworks 40V 21" mower features a rear-wheel-drive power assist mode, which aids in propelling the mower forward and can be particularly beneficial for users who prefer not to rely solely on physical force to push the mower. (4 reviews)

    • “It can barrel up a hill in a way larger gas power mowers, even with an SP function, could not.”

    • “The self propelling drive, with a large rear wheel, actually propelled this mower up the hill will 10% the effort.”

    • “In this rear wheel drive power assist mode, at the slowest speed I thought it went too fast. It takes too much time to dis-engage and re-engage the power assist mode. Since the rear wheels are the drive wheels, it's difficult to lift them off of the ground to make sharp turns, or back up briefly to reposition.”

    • “powered drive for hills”

  • The mower offers an easy way to adjust the blade height, which is an improvement over some gas-powered mowers. (4 reviews)

    • “it is far easier to adjust the blade height”

    • “Height adjustment”

    • “Adjustability is good”

    • “I did have to raise the height to cut the grass without stalling and then cut it again to the proper height a few days later.”

  • The mower has a mulching feature, which is helpful for users who prefer to mulch their grass clippings as opposed to collecting them. (4 reviews)

    • “Now that I am back to mulching and cutting every three days, two batteries are enough.”

    • “Battery life has been great on the mulch setting- have about 5000 sqft of grass area”

    • “I really love the bagged mulching the mower does.”

    • “Very even and mulches well.”

  • The handle height is adjustable, providing comfort for users of different heights and preferences. (1 review)

    • “Also like that the handle can be lowered from the max length, while still allowing the mower to start.”

4 reasons not to buy

  • Multiple reviews mention concerns about the battery life of the Greenworks 40V 21" lawn mower. Users report that the mower struggles to maintain charge, particularly when utilizing the self-propelled feature, leading to a maximum usage time of around 30 minutes before a recharge is necessary. (38 reviews)

    • “Don't expect 40 minutes on a battery, especially if you are using the self-propelled feature. Even being judicious in using it, I found that 30 minutes was about the limit.”

    • “the battery only lasted 30 minutes while mulching”

    • “Don't like the smaller 40v battery. EGO uses a 56v battery and will mow for an hour. This one gets you a little more than halfway there!”

    • “Battery just finished front lawn before dying. Second battery cut almost 3/4 of backyard before dying and had to finish with gas mower. Guess I have to buy it least two more batteries to be able to use self propelled.”

    • “It can go about 35 minutes before the battery runs flat.”

    • “the fact that it only runs for just over 20 minutes before needing a recharge”

    • “Now it starts fine and runs for about 30-45 seconds before it dies. The power drive dies at the same time. Battery is fully charged.”

    • “Worth buying a second battery so you can finish a medium sized yard in one go, mine is nearly dead after mowing our .13 acre lot.”

    • “The battery life is awful even though I don’t use the power propulsion (I push it). It barely does half of my small yard on a full charge.”

  • Though the mower is generally praised for its cutting power, it may not be sufficient for very tall or wet grass, as it can bog down under challenging conditions. (16 reviews)

    • “Probably not enough for foot long wet grass but plenty for normal mowing.”

    • “Second, the mower absolutely does not have the power of a gas mower (cutting). It will bog down, when you reach the top of the hill.”

    • “It did tend to stall a few times. It can use a little more power.”

    • “It makes for a super frustrating mowing experience, especially when you just want to knock down the higher grass after a rain.”

    • “This mower doesn't seem to have enough power to handle even slightly thicker grass. It did fine for a few minutes in thin grass, but grass covered by trees was too much for it and it struggled before sputtering out and killing the battery.”

    • “if the grass got too high the battery ran out faster”

    • “it bogs down so bad I keep having to restart it.”

  • The cost of extra batteries is pretty steep, so it's a big extra expense if you need to mow for longer periods without stopping. (14 reviews)

    • “I'm not sure why, but the cost of a second (spare) battery is astronomical -- beyond $175 on Amazon. And, there's no special bundle deal when you buy the mower.”

    • “Guess I have to buy at least two more batteries to be able to use self propelled.”

    • “I do recommend that you purchase a second battery so you will not run out of battery especially mowing large lawns.”

    • “Also I was smart enough to buy 1 extra battery -I should have bought 3 extra batteries”

    • “I would advise to have at least 2-3 batteries to do a complete lawn.”

    • “I’m considering buying a second battery, although they seem fairly expensive.”

    • “plan to buy MANY more batteries to be able to mow your yard.”

    • “Don’t buy without a backup battery.”

    • “It’s either buy an extra as back up, or cut the front lawn and 1/3 if the back.”

    • “To make this mower work on our flat property, we need a total of six batteries all fully charged. Which turns this expense into an outrageous expense.”

  • Despite being lighter than some gas mowers, the electric mower is still quite heavy, which can be a downside for some, especially when the battery dies and manual pushing is required. (12 reviews)

    • “First, the weight. It is not 21lbs. as stated in the description, it is more like 70lbs.”

    • “I have to pack up the whole thing and pack this heavy box around”

    • “the mower is not light”

    • “Its mows nicely but its a bit heavy for manual use like around shrubs and trees.”

    • “I had difficulty lifting it out of the box.”

    • “The mower is also not "21.65 Pounds" but closer to 68 Pounds (box shows 68.6 LB and Greenworks site shows Weight (without battery pack) 29 kg (64 lbs.))”

    • “you are using up the battery life, and your strength to push it as you are literally forcing the grass to lye down”

    • “Trust me, it weighs MUCH more than the stated 21.65 pounds. Like 60 lbs more.”

    • “The weight of it is grossly understated at 21.6 pounds. Shipping weight on mine was 83 pounds and the assembled weight of the mower is around 70 pounds.”

    • “The unit is fairly havvy at 66 pounds but that really has not been much of an issue.”

    • “Specs said it was 21lbs. Sold! Except when it arrived, it was actually 71lbs!”

Bottom Line

The Greenworks 40V 21" lawn mower is a solid choice for easy mowing. It's self-propelled, helping you tackle hills with ease, and starts up without a fuss. No need for gas or pull-strings, it's battery-powered, quiet, and simple to clean. Adjusts to your height and stores upright to save space. However, the battery might tap out after 30 minutes, especially on tough grass, and extra batteries cost a fair bit. It's a bit heavy, but overall, it's user-friendly and efficient.


Cutting Width (in)21 inch
FeaturesElectric Start, Rear Discharge, Mulching, Bagging, Side Discharge
Max Cutting Height3-3/4"
Min Cutting Height1-3/8"
Power SourceBattery
CategorySelf Propelled Mowers
Warranty2 Years
Weight46 lbs.

Video Reviews

Special Features

  • 40V Lithium-Ion Technology: This mower uses a powerful battery that lets you cut the grass for up to 45 minutes on a single charge. It's like having the muscle of a gas mower without needing to fill up on fuel.
  • Brushless Motor: The motor inside this mower is built to last longer, work quieter, and give you more cutting power, which means it can handle tough grass with less fuss.
  • 21-Inch Durable Steel Deck: The part that houses the blades is made of strong metal so it can take a beating and keep on mowing for years.
  • Single Lever Height Adjustment: You can easily change how high or low you cut the grass by moving just one handle, with seven settings to choose from.
  • 3-in-1 Design: This mower is pretty handy. You can choose to collect the grass clippings in a bag, spit them out the side, or chop them up to feed your lawn.
  • Self-Propelled Rear Wheel Drive: The mower helps push itself along, especially up hills or through tough spots, which means less work for you.
  • Vertical Storage: When you're done mowing, you can stand this mower up on its end, so it takes up less space in your shed or garage.
  • Low Maintenance: No need for gas, oil changes, or tune-ups. Just press a button to start it, and enjoy a quieter mowing experience without any smelly fumes.
  • Compatible Tool Ecosystem: The battery that comes with this mower isn't a one-hit-wonder. You can use it with over 75 other tools from the same brand, saving you money and garage space.


  • Q:

    Does the device operate with both batteries simultaneously, or does one serve as a backup?

  • A:

    The device is engineered with a primary battery slot for operation and a secondary slot designated for battery storage.

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