MightyMow
MightyMow 40V 21-Inch Self-Propelled Lawn Mower: Brushless Power
The MightyMow 40V 21-inch is a brushless cordless mower that punches above its weight class , a 21-inch cutting deck and rear-wheel variable speed drive on a 23.8-lb frame is genuinely rare. It ships with two 8.0Ah batteries and a dual charger, making it a ready-to-run package suited for small-to-medium yards where convenience and low maintenance matter most.
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Last updated: . Based on our analysis of 364 lawn mowers.
What Sets It Apart
Key specification highlights based on our analysis.
21.0-Inch Cutting Deck
Wide cutting path reduces passes (walk-behind avg: 18.0 in)
Rear-Wheel Drive
Better traction on hills and slopes vs front-wheel drive
Variable Speed Control
Adjustable pace to match your walking speed
23.8 lbs
Lightweight for easier maneuverability (walk-behind avg: 53.1 lbs)
Considerations
Polymer Cutting Deck
Lightweight but less durable than steel; won't rust
Why We Recommend It
- 01.
Dual 40V 8.0Ah battery setup extends total runtime and lets one charge while the other runs
- 02.
21-inch polymer cutting deck cuts a wider path than most competitors in this class (avg 18 inches), reducing lapping passes
- 03.
Rear-wheel drive with variable speed control lets you dial in your walking pace , useful on uneven or gently sloped lawns
- 04.
Push-button start eliminates the pull-cord frustration common to gas mowers
- 05.
23.8-lb weight makes it easy to lift over obstacles, load into a car, or store on a shelf
Considerations
- 01.
Battery life draws mixed reviews , some users report the charge depletes faster than expected on dense or wet grass, limiting effective range per battery
- 02.
Polymer cutting deck is lighter and rust-proof but less impact-resistant than steel decks if you hit rocks or roots frequently
- 03.
No mention of a grass bag capacity spec, which makes it harder to gauge bagging efficiency before buying
Technical Specifications
| Feature | Specification |
|---|---|
| Mower Type | Self propelled |
| Power Source | Battery |
| Cutting Width | 21" |
| Deck Material | Polymer |
| Height Positions | 6 |
| Battery | 40V 8Ah |
| Drive | Rear wheel, Variable Speed |
| Weight | 23.8 lbs |
| Start Type | Push button |
Power & Performance
The 40V brushless motor delivers consistent torque without the carbon brush wear that degrades performance in brushed motors over time. Customers confirm it handles grass up to 6 inches tall, which suggests adequate power headroom for occasional missed mowing cycles.
In normal conditions , maintained lawns with standard turf height , the brushless motor should sustain cutting efficiency without bogging down.
Cutting System
The 21-inch polymer cutting deck is 3 inches wider than the walk-behind category average, meaning fewer overlapping passes on a given lawn area. Six cutting height positions give you meaningful flexibility from a close trim to a taller cut that protects grass roots in dry seasons.
The 3-in-1 discharge system covers mulching, bagging, and side discharge, so you're not locked into a single grass disposal method.
Drive & Handling
Rear-wheel drive self-propulsion is a meaningful upgrade over front-wheel drive on any lawn that isn't perfectly flat , rear wheels push from behind the operator's feet rather than pulling from the front, which keeps traction even when the front deck tips slightly on a grade. Variable speed control means you're not locked to a fixed pace; match it to your stride and the terrain.
At 23.8 lbs , roughly half the weight of an average walk-behind , fatigue stays low even on longer sessions.
Battery / Fuel
Two 40V 8.0Ah batteries are included, each representing 320Wh of capacity, which is a solid per-battery rating for this voltage class. In practice, runtime per battery will vary with grass density and drive motor load, and customer feedback suggests heavier conditions can drain a battery faster than expected.
The included dual charger lets you top up one battery while running on the other, which partially offsets the range concern on medium-sized yards.
Who Is This Mower For?
Ideal For
- ✓ Homeowners with up to 1/2-acre flat-to-gently-sloped yards who want the wider 21-inch deck to cut mowing time without a heavy machine
- ✓ Eco-conscious users who want zero direct emissions and quieter operation compared to gas , the brushless motor and 40V platform deliver both
- ✓ People tired of gas maintenance: no oil changes, spark plug replacements, or carburetor headaches , push-button start and done
- ✓ Anyone who wants a complete out-of-box setup , both batteries and the dual charger are included so there's nothing extra to buy on day one
Not Ideal For
- ✕ Large property owners (over 3/4 acre) who may burn through both batteries before finishing , single-pass coverage is better with a higher-voltage or zero-turn platform
- ✕ Owners with steep, hilly terrain where rear-wheel drive helps but may still not provide the traction of a more powerful AWD or high-torque gas mower
- ✕ Users who frequently mow heavily overgrown or very thick grass , battery drain accelerates under load, reducing effective runtime per charge
Customers consistently report the mower arrives essentially ready to use with minimal setup , the product listing notes no assembly required, and buyer feedback aligns with a straightforward unboxing-to-mowing experience.
Charge both batteries fully before the first use to calibrate capacity and get a realistic sense of runtime on your specific lawn
Attach the battery that feels firmest in the slot first , polymer housings can have slight manufacturing variation and one port may seat more snugly than the other
Warranty details for the MightyMow 40V are not published in the available product specifications , verify current coverage terms directly with MightyMow or on the Amazon product listing before purchasing, as battery-included bundles sometimes carry split coverage between the mower body and batteries.
FAQ
How long does each 8.0Ah battery last on a single charge?
MightyMow does not publish a specific runtime figure in the product specifications. Based on the 40V 8.0Ah rating (320Wh per battery), expect roughly 30-45 minutes of combined drive and cutting on a maintained lawn , less on thick or wet grass.
The included dual charger and second battery help bridge any gap on larger yards.
Is the 21-inch cutting deck self-propelled on all terrain types?
The rear-wheel drive variable speed system engages on most residential terrain including gentle slopes. Rear-wheel drive specifications give it better hill traction than front-wheel alternatives because the drive wheels sit under the operator's center of gravity.
Steep or uneven terrain may still require manual assist on sharp inclines.
Does the MightyMow 40V work for tall or overgrown grass?
Customer feedback confirms it can cut grass around 6 inches tall, so it handles moderate overgrowth. For very thick or heavily overgrown lawns, expect faster battery drain as the brushless motor draws more current under load , consider doing a first pass on the highest of the 6 cutting height positions before dropping to your target height.
Is the polymer cutting deck durable enough for normal yard use?
Polymer decks are standard on many modern cordless mowers because they are lightweight, completely rust-proof, and handle typical residential turf without issue. The trade-off is impact resistance , a polymer deck can crack if it takes a hard strike from a rock or root edge, whereas a steel deck would dent but generally stay intact.
For lawns with debris or hidden obstacles, clearing the area before mowing is good practice regardless of deck material.
Can I use the 40V batteries in other MightyMow tools?
Battery cross-compatibility depends on whether MightyMow uses a shared 40V platform across their tool lineup. The product listing does not specify platform compatibility with other tools , check MightyMow's product ecosystem directly to confirm whether these 8.0Ah batteries are interchangeable with other 40V MightyMow equipment.
How does the variable speed drive work and how fast does it go?
The variable speed drive is controlled via the handle , typically a bail or thumb lever that you squeeze or slide to engage the rear-wheel drive and increase or decrease pace. No maximum speed figure is published in the specifications, but variable speed on self-propelled mowers typically ranges from about 0.5 to 3.5 mph.
The ability to match drive speed to your natural walking pace is the main benefit, reducing effort on larger passes.
Bottom Line
The MightyMow 40V 21-inch is a well-rounded cordless self-propelled mower for homeowners who want a wider-than-average deck, genuine rear-wheel drive traction, and a zero-maintenance power source , all under 24 lbs. The dual-battery bundle removes the biggest barrier to electric adoption: range anxiety. Battery runtime on thick grass is the one real caveat to weigh before buying.
Best for small-to-medium flat or gently sloped yards where zero-emissions, push-button convenience, and a wide 21-inch cut are the priorities.
Consider alternatives if you have steep hills requiring more torque, a large property where even two batteries may fall short, or a preference for a steel deck in debris-heavy yards.
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