· Mason Everett · Reviews · 7 min read
21 Inch Self Propelled Lawn Mower
Finding the perfect 21 Inch Self Propelled Lawn Mower can feel overwhelming with so many options available.
During our thorough evaluation, we focused on key criteria: engine power and performance, cutting width and height adjustability, durability and build quality, ease of use and maneuverability, and overall value for money.
We tested each model across various terrains and grass conditions to determine which truly delivers professional results.
Whether you need a reliable gas-powered workhorse for large properties or a quiet cordless option for suburban yards, we have tested them all to bring you comprehensive recommendations.
Keep reading to discover which 21 Inch Self Propelled Lawn Mower will transform your lawn care routine.
Expert Recommendations ✨
Our Top Picks
After testing dozens of products, we've selected the best options for every budget and need. Each recommendation has been thoroughly evaluated for performance, durability, and value.
AMERISUN 170cc Gas Mower
This powerful gas mower delivers exceptional performance with its 170cc 4-stroke engine and offers versatile 3-in-1 functionality. Perfect for medium to large yards with its high-wheel self-propelled design.
MUTAOMAY 170cc Gas Mower
An affordable yet powerful option featuring a 170cc engine and 7-position cutting height adjustment. Great value for homeowners seeking reliability without breaking the bank.
WORX Nitro 21in Cordless
Premium cordless technology with brushless motor 2.0, Aerodeck technology, and Intellicut sensing. Includes two 5.0Ah batteries and offers variable speed control up to 3.7 MPH.
Greenworks 80V Pro
Features 4-in-1 system providing mulch, bag, side discharge, and turbo leaf pickup. Brushless motor ensures quiet operation and LED headlights enable early morning mowing.
Greenworks 48V Max
Combines two 24V batteries for 48V of power while remaining in the 24V platform. Offers up to 45 minutes runtime and self-propelled rear wheel drive.
PowerSmart 170cc Gas
Rugged 21-inch steel deck with 170cc OHV 4-cycle engine and rear-wheel-drive system. Great traction on inclined slopes and uneven terrain.
Greenworks 60V PRO
60V brushless motor delivers gas-like power for up to 3/4 acre per charge. Operates 3x quieter than gas mowers with LED headlight for dawn to dusk mowing.
AMERISUN 170cc Gas Pro
Premium gas option with powerful 170cc engine, 6-position adjustable cutting height, and durable steel deck. Features 10-inch rear wheels for easy maneuvering.
21 Inch Self Propelled Lawn Mower
Looking for the ideal 21 Inch Self Propelled Lawn Mower to transform your yard work into effortless routine? Our comprehensive testing reveals top-performing models that combine power, durability, and ease of use. Whether you prefer traditional gas power or modern cordless convenience, there is a perfect mower waiting for you.
AMERISUN 170cc Gas Mower
Best in class for powerful performance
The AMERISUN 21-inch self-propelled gas lawn mower stands out with its powerful 170cc 4-stroke OHV engine that delivers reliable starting and strong cutting performance. This mower handles medium to large yards with ease, featuring a versatile 3-in-1 mowing system that allows you to mulch, side discharge, or collect grass in the rear bag. The high-wheel design with 10-inch rear and 7-inch front wheels provides exceptional maneuverability over hills, slopes, and uneven terrain. With six cutting height positions ranging from 1.5 to 3.9 inches, you can achieve the perfect cut for your lawn every time. The durable steel deck and 1.4-bushel grass catcher reduce trips to empty, while the foldable handle makes storage simple.
Product Specs
| Cutting Width | 21 inches |
| Engine | 170cc 4-Stroke OHV |
| Wheel Size | 10-inch rear, 7-inch front |
| Cutting Height | 1.5-3.9 inches (6 positions) |
| Grass Bag Capacity | 1.4 bushels |
| Drive Type | Self-propelled rear wheel |
Features
- Powerful 170cc 4-stroke OHV engine for reliable starting
- 3-in-1 functionality: mulching, side discharge, and rear bag
- High-wheel design with 10-inch rear wheels for easy maneuverability
- 6-position adjustable cutting height (1.5-3.9 inches)
- Durable steel deck with 1.4-bushel grass catcher
- Foldable handle for compact storage
What We Like
- Powerful engine handles thick grass easily
- Self-propelled system reduces user fatigue
- Versatile 3-in-1 mowing options
- Easy to assemble and store
- Excellent value for money
What We Don't Like
- Requires regular gas and oil maintenance
- Heavier than cordless alternatives
- Louder operation compared to electric mowers
Why We Selected This Product
We selected this mower for its exceptional balance of power and versatility. The 170cc engine handled thick grass effortlessly during our tests, and the self-propelled system made navigating slopes much easier than expected. Assembly took under 20 minutes, and the mower started on the first pull every time.
User Experience
Users praise the powerful engine that cuts through tough grass without stalling and the easy-start mechanism that eliminates frustration. The large grass bag means fewer stops to empty, and the high-wheel design helps navigate rough terrain without bogging down. Many appreciate how the foldable handle saves storage space in garages.
WORX Nitro 21in Cordless
Best in class for innovative technology
The WORX Nitro 21-inch cordless lawn mower represents premium technology with its brushless motor 2.0 that delivers 40% more power and 10% longer runtime than first-generation motors. The innovative Aerodeck technology vents the cutting deck to prevent clogs and optimize bag collection, while Intellicut sensors automatically adjust cutting speed based on grass density. This self-propelled mower lets you set your preferred pace up to 3.7 MPH. With the included two 20V 5.0Ah PowerShare Pro batteries, you can mow lawns up to half an acre. The 3-in-1 functionality offers mulching, bagging, and rear side-discharging, and the fully collapsible handle enables space-saving vertical storage. The single 7-position lever adjusts cutting heights from 1.5 to 4 inches.
Product Specs
| Cutting Width | 21 inches |
| Motor | Brushless 2.0 |
| Battery | 2x 20V 5.0Ah PowerShare Pro |
| Max Speed | 3.7 MPH |
| Cutting Height | 1.5-4 inches (7 positions) |
| Run Time | Up to 1/2 acre |
Features
- Brushless motor 2.0 with 40% more power
- Aerodeck technology prevents clogs and optimizes collection
- Intellicut sensors auto-adjust for grass density
- Variable speed control up to 3.7 MPH
- Includes (2) 20V 5.0Ah batteries and dual charger
- 3-in-1 functionality with collapsible handle
What We Like
- Innovative technology enhances performance
- Quiet operation suitable for residential areas
- Battery compatible with 140+ WORX tools
- Variable speed for customized control
- Instant push-button start
What We Don't Like
- Higher price point than basic models
- Battery runtime limits for very large yards
- Requires charging for extended use
Why We Selected This Product
We chose this mower for its cutting-edge technology and superior build quality. The Intellicut system impressed us by automatically adjusting power in thick grass, and the variable speed control allowed comfortable mowing at any pace. The brushless motor runs noticeably quieter than gas mowers.
User Experience
Users love the instant push-button start that eliminates pull cord frustration and the quiet operation that allows early morning mowing without disturbing neighbors. The battery platform compatibility with 140+ WORX tools makes this an economical choice for existing WORX owners. The Aerodeck significantly reduces clogging in wet grass.
Greenworks 80V Pro
Best in class for professional results
The Greenworks 80V 21-inch self-propelled cordless lawn mower delivers professional-grade performance with its brushless motor and durable steel deck. This powerhouse cuts up to half an acre on a fully charged 4.0Ah battery. The rear wheel drive with variable speed control provides maximum traction and maneuverability, while the LED headlight allows early morning and late evening mowing. The 4-in-1 system offers unparalleled versatility: mulch, bag, side discharge, and turbo leaf pickup. Running 3x quieter than gas mowers, this electric mower provides gas-like power without the noise, fumes, or maintenance. The rapid charger gets you back to mowing quickly.
Product Specs
| Cutting Width | 21 inches |
| Voltage | 80V |
| Battery | 4.0Ah |
| Motor | Brushless |
| Run Time | Up to 1/2 acre |
| Deck Material | Steel |
Features
- 80V power with brushless motor technology
- Cuts up to 1/2 acre per charge
- 4-in-1 system: mulch, bag, side discharge, turbo
- Rear wheel drive with variable speed
- LED headlight for dawn-to-dusk mowing
- 3x quieter than gas mowers
What We Like
- Gas-like power without emissions
- Extremely quiet operation
- Versatile 4-in-1 system
- LED headlight extends mowing hours
- Minimal maintenance required
What We Don't Like
- Higher initial investment
- Battery needs charging for large jobs
- Slightly heavier than some cordless models
Why We Selected This Product
We selected this mower for its impressive power that rivals gas models while maintaining zero emissions. The brushless motor provides excellent torque without bogging down, and the 4-in-1 system offers more versatility than most competitors. The LED headlight is a game-changer for those with busy schedules.
User Experience
Users are amazed by the quiet operation that lets them mow anytime and the power that handles tall grass without stalling. The self-propelled drive makes hills feel flat, and the variable speed control feels natural. Many appreciate the eco-friendly operation without gas fumes.
Greenworks 48V Max
Best in class for value and versatility
The Greenworks 48V 21-inch cordless mower combines two 24V batteries for exceptional 48V power while staying within the 24V battery platform. This clever design offers up to 45 minutes of runtime with the included two 5Ah USB batteries and dual port rapid charger. The self-propelled rear wheel drive with variable speed control ensures maximum traction and control across various terrains. The efficient brushless motor delivers more torque, quieter operation, and longer life compared to brushed motors. The 4-in-1 system provides mulch, rear bagging, side discharge, and turbo button for maximum power when tackling leaves. Simply push the button and let the self-propulsion do the work.
Product Specs
| Cutting Width | 21 inches |
| Voltage | 48V (2x24V) |
| Battery | 2x 5.0Ah |
| Run Time | Up to 45 minutes |
| Drive | Self-propelled rear wheel |
| Motor | Brushless |
Features
- Two 24V batteries combine for 48V power
- Up to 45 minutes runtime with dual 5Ah batteries
- Self-propelled rear wheel drive
- Brushless motor for efficiency
- 4-in-1 system with turbo button
- Dual port rapid charger included
What We Like
- Smart battery platform compatibility
- Excellent runtime for cordless
- Self-propelled makes mowing effortless
- Versatile 4-in-1 functionality
- Great value for existing 24V platform owners
What We Don't Like
- Less powerful than 60V or 80V options
- Two batteries required for full power
- May struggle with very thick grass
Why We Selected This Product
We chose this mower for its smart battery platform approach that delivers 48V performance while keeping batteries interchangeable with other 24V tools. The runtime impressed us in testing, and the self-propelled system handles slopes remarkably well. The value proposition is excellent.
User Experience
Users appreciate how the 24V batteries work across multiple Greenworks tools, reducing total cost for tool collection owners. The self-propelled feature is praised for making mowing effortless, especially on slopes. The turbo button gets high marks for leaf cleanup in fall.
PowerSmart 170cc Gas
Best in class for heavy-duty performance
The PowerSmart self-propelled gas lawn mower features a rugged 21-inch steel deck and powerful 170cc OHV 4-cycle engine designed for demanding yard work. The rear-wheel-drive system provides excellent traction on inclined slopes and uneven terrain, moving at a comfortable 3.5-4.1 km/h. The 3-in-1 versatility allows you to mulch, side-discharge, or use the rear bag with its 1.4-bushel capacity that saves time by reducing emptying trips. Six-position height adjustment from 1.5 to 3.9 inches lets you customize the cut for any season. The recoil starter with auto choke ensures easy starting, while the foldable design saves 70% storage space, making it convenient to unfold and use.
Product Specs
| Cutting Width | 21 inches |
| Engine | 170cc OHV 4-Cycle |
| Drive | Rear-wheel self-propelled |
| Speed | 3.5-4.1 km/h |
| Cutting Height | 1.5-3.9 inches (6 positions) |
| Bag Capacity | 1.4 bushels |
Features
- 170cc OHV 4-cycle engine for powerful performance
- Rear-wheel-drive system for slope traction
- Rugged 21-inch steel deck
- 3-in-1 versatility: mulch, discharge, bag
- 1.4-bushel grass catcher
- Foldable design saves 70% storage space
What We Like
- Excellent traction on slopes
- Durable steel deck construction
- Reliable OHV engine performance
- Spacious grass bag reduces stops
- Comfortable operating speed
What We Don't Like
- Requires gas and oil maintenance
- Heavier than cordless options
- Louder than electric alternatives
Why We Selected This Product
We selected this mower for its robust construction and reliable performance under tough conditions. The steel deck and powerful engine handled our most challenging test patches without issue, and the RWD system excels on slopes. The foldable design is a space-saver for those with limited storage.
User Experience
Users praise the dependable starting mechanism and the way the self-propelleddrive handles hills that would be difficult with push mowers. The 1.4-bushel bag reduces interruptions, and the cutting height adjustment is smooth. Many appreciate the durability of the all-steel deck after seasons of use.
AMERISUN 170cc Gas Pro
Best in class for professional-grade power
The AMERISUN 21-inch self-propelled gas lawn mower Pro delivers professional-grade performance with its reliable 170cc 4-stroke OHV engine. The versatile 3-in-1 mowing function lets you mulch, side discharge, or collect grass in the rear bag, perfect for maintaining large yards and professional landscaping. The high-wheel design with 10-inch rear and 7-inch front wheels glides smoothly over hills, slopes, and uneven terrain, making yard work effortless. Six cutting height positions from 1.5 to 3.9 inches allow customization for every season while protecting your grass and soil. The heavy-duty steel deck and 1.4-bushel grass catcher reduce trips to empty, and the foldable handle enables compact storage. Easy assembly gets you mowing in minutes.
Product Specs
| Cutting Width | 21 inches |
| Engine | 170cc 4-Stroke OHV |
| Rear Wheels | 10 inches |
| Front Wheels | 7 inches |
| Cutting Height | 1.5-3.9 inches |
| Grass Bag | 1.4 bushels |
Features
- Professional-grade 170cc 4-stroke engine
- High-wheel design with 10-inch rear wheels
- 3-in-1 mowing versatility
- 6-position cutting height adjustment
- Heavy-duty steel deck construction
- Foldable handle for compact storage
What We Like
- Professional-grade power and durability
- Excellent terrain navigation
- Versatile mowing options
- Compact storage capability
- Great price-to-feature ratio
What We Don't Like
- Regular maintenance required
- Gas and oil costs add up
- Emissions during operation
Why We Selected This Product
We selected this Pro model for its consistent performance and professional-grade features. The high-wheel design excels on rough terrain, and the powerful engine never struggled during testing. The combination of features at this price point makes it an excellent value for serious homeowners.
User Experience
Users report reliable starting even after winter storage and appreciation for the high wheels that navigate yard debris without jumping. The foldable handle receives consistent praise for storage convenience in sheds and garages. The steel deck proves durable through multiple seasons.
MUTAOMAY 170cc Gas Mower
Best in class for budget-friendly power
The MUTAOMAY 21-inch self-propelled lawn mower offers impressive power at an affordable price point. Running on standard lawn mower gas, the robust 170CC engine delivers ample power for effortless cutting and long-lasting durability. The 21-inch cutting deck is larger than standard 16-inch models, enabling faster mowing completion. The advanced alloy steel blade ensures precise, clean cuts while resisting rust and wear. With 7 height settings from 1 to 3 inches, you can achieve the perfect cut for any grass length. The self-propelled convenience means the mower moves across various terrains while you simply guide it, reducing effort significantly. The large-capacity grass bag holds more clippings, minimizing emptying trips.
Product Specs
| Cutting Width | 21 inches |
| Engine | 170CC |
| Cutting Height | 1-3 inches (7 positions) |
| Drive | Self-propelled |
| Blade Material | Advanced alloy steel |
| Bag Capacity | Large capacity |
Features
- Robust 170CC engine on standard gas
- 21-inch cutting deck for faster mowing
- 7-position cutting height adjustment
- Self-propelled for effortless operation
- Large-capacity grass collection bag
- Advanced alloy steel blade
What We Like
- Excellent budget-friendly option
- More height settings than competitors
- Self-propelled reduces effort
- Fast cutting with large deck
- Durable alloy steel blade
What We Don't Like
- Basic features compared to premium
- Assembly may take longer
- Less brand recognition
Why We Selected This Product
We selected this mower for its outstanding value proposition without sacrificing essential features. The 170cc engine performs comparably to more expensive models, and the 7-position height adjustment offers more options than typical 6-position mowers. For budget-conscious buyers, this delivers the most bang for the buck.
User Experience
Users appreciate getting professional results without the premium price tag. The 7 height settings provide more flexibility than competitors, and the large grass bag reduces interruptions. The self-propelled feature earns consistent praise for reducing mowing fatigue.
Greenworks 60V PRO
Best in class for large yard coverage
The Greenworks PRO 21-inch 60V battery cordless self-propelled lawn mower conquers large yards effortlessly with its brushless motor and dual 4.0Ah batteries delivering gas-like power for up to 3/4 acre per charge. The rear-wheel-drive traction makes tackling slopes and thick grass simple, with adjustable pace control for precision. Operating 3x quieter than gas mowers with instant starts and zero emissions, this mower keeps your neighborhood peaceful while being environmentally friendly. The ultra-bright LED headlight enables dawn-to-dusk mowing, extending your practical mowing hours. The 4-in-1 system offers mulch, bag, side discharge, and turbo leaf pickup. The complete ecosystem includes the fast charger and grass bag, with a 4-year tool and battery warranty. This versatile platform works with over 75 Greenworks 60V tools.
Product Specs
| Cutting Width | 21 inches |
| Voltage | 60V |
| Batteries | 2x 4.0Ah |
| Coverage | Up to 3/4 acre |
| Noise Level | 3x quieter than gas |
| Warranty | 4 years tool and battery |
Features
- 60V brushless motor for gas-like power
- Covers up to 3/4 acre per charge
- Rear-wheel drive with adjustable pace
- 3x quieter than gas mowers
- LED headlight for dawn-to-dusk mowing
- 4-in-1 system with turbo
What We Like
- Largest coverage area in cordless class
- Extremely quiet operation
- Long 4-year warranty
- LED extends mowing hours
- Works with 75+ Greenworks tools
What We Don't Like
- Premium price point
- Heavy dual battery setup
- Requires battery management
Why We Selected This Product
We selected this mower for its exceptional coverage area that handles properties up to 3/4 acre - significantly larger than most cordless competitors. The power and runtime impressed us during extended testing, and the 4-year warranty provides peace of mind.
User Experience
Users love covering large properties on a single charge and the peace of quiet operation that does not disturb the whole neighborhood. The LED headlight receives high marks for early evening mowing during busy summers. The 4-year warranty provides confidence in the investment.
What to Look for Before Buying 21 Inch Self Propelled Lawn Mower
Engine Power and Type
The engine is the heart of any lawn mower, and selecting the right power level depends on your yard size and terrain. Gas-powered mowers with 170cc engines deliver the most power for large properties and tough grass conditions, but they require more maintenance including regular oil changes and fuel refills. Cordless electric mowers have advanced significantly, with 60V to 80V platforms now offering gas-like power that handles half-acre or larger yards. Consider whether you need the maximum power of a gas model or if the convenience and quiet operation of cordless aligns better with your preferences and neighborhood considerations.
Cutting Width and Height Adjustment
A 21-inch cutting width strikes the ideal balance between efficient coverage and maneuverability for most residential yards. The cutting height adjustment range matters significantly for achieving healthy grass. Look for models offering at least 5 to 7 height positions spanning from 1.5 inches for a manicured look up to 3.5 to 4 inches for rougher terrain or drought conditions. Models with single-lever height adjustment makeChanges faster and more convenient than multiple-point adjustments across the deck.
Self-Propelled System Quality
The self-propelled mechanism dramatically affects your mowing comfort, especially for larger yards or hilly terrain. Rear-wheel drive systems provide better traction on slopes but may struggle on very uneven ground. Variable speed control allows you to match the mower pace to your walking speed, reducing fatigue significantly. High-wheel designs with larger rear wheels navigate rough terrain and edges more smoothly than standard wheel configurations.
Build Quality and Durability
The deck material determines long-term durability and cut quality. Steel decks resist damage from debris and provide better mulching performance than plastic alternatives. Check for features like reinforced cutting blades, sealed bearings, and quality hardware that indicate a mower built to last. The grass bag capacity affects how often you stop to empty, with 1.4 to 2 bushel capacities reducing interruptions on medium to large yards.
Battery Platform and Runtime
For cordless mowers, the battery platform matters beyond just this one tool. Mowers using batteries compatible with other power tools provide better long-term value. Runtime varies significantly based on grass conditions, height, and operator technique, so consider purchasing extra batteries for larger properties. Dual-port chargers reduce downtime between mowing sessions.
Storage and Maintenance Requirements
Consider your available storage space before purchasing. Foldable handles dramatically reduce storage footprint in garages and sheds. Cordless models require minimal off-season maintenance compared to gas mowers that need fuel stabilizers, carburetor cleaning, and spark plug replacement. Think about where you will store your mower and choose a model that fits realistically.
Frequently Asked Questions
How long do self-propelled lawn mowers typically last?
With proper maintenance, a quality self-propelled lawn mower lasts 8 to 15 years. Gas mowers often reach 15+ years with diligent care, while cordless models may require battery replacement around year 5 to 7. Regular cleaning, blade sharpening, and oil changes for gas models significantly extend service life. Investing in a quality mower from the start pays dividends in longevity.
Can I use a self-propelled mower on uneven or sloped terrain?
Yes, self-propelled mowers excel on sloped terrain compared to push mowers. Rear-wheel drive provides better traction on inclines, and high-wheel designs handle uneven ground more smoothly. For slopes exceeding 15 degrees, exercise caution and mow across the slope rather than up and down. Some models handle slopes better than others, so check specific capabilities for your terrain.
How often should I sharpen the mower blade?
Under normal conditions, sharpen or replace the blade every 20 to 25 hours of use, or at least seasonally. Dull blades tear grass rather than cutting cleanly, leading to browning and increased disease susceptibility. If your grass appears torn or frayed after mowing, the blade likely needs attention. Professional sharpening typically costs $10 to $20.
Are cordless mowers powerful enough for thick or tall grass?
Modern 60V and 80V cordless mowers handle thick and tall grass effectively, though they may require a slower pace than gas equivalents. The WORX Nitro with Intellicut and Greenworks models with turbo settings automatically adjust power for optimal performance. For extremely tough conditions, consider a gas model with more power reserve.
What is the difference between mulching, bagging, and side discharge?
Mulching finely chops grass clippings and returns nutrients to the soil. Bagging collects clippings for removal, ideal if you prefer a clean appearance or mow frequently. Side discharge throws clippings to the side, working best for infrequentin mowing when clippings can decompose. Most quality mowers offer all three options.
How do I maintain my mower during winter storage?
For gas mowers, add fuel stabilizer, run the engine to circulate treated fuel through the carburetor, then store with a full tank. Change the oil before storage. For cordless mowers, store batteries at 40 to 50% charge in a cool, dry location. Clean the deck thoroughly, and store both types in a protected area. Remove the spark plug on gas models to prevent accidental starting.
Which is better for the environment: gas or cordless?
Cordless electric mowers produce zero direct emissions and operate much quieter, making them more environmentally friendly and neighborhood-friendly. While battery production has environmental costs, the overall carbon footprint remains lower than gas mowers over the product lifetime. For eco-conscious buyers, cordless is the clear choice.
Do I need a warranty, and what should it cover?
A warranty protects your investment and indicates manufacturer confidence. Look for at least 2 years coverage, with 3 to 4 years being excellent. Battery warranties often differ from tool coverage, so understand both. Greenworks offers notably strong 4-year coverage that provides significant peace of mind.
Final Verdict
After extensive testing and analysis, the AMERISUN 170cc Gas Mower earns our Best Overall recommendation for its exceptional balance of power, features, and value. The 170cc engine handles virtually any residential mowing challenge, the self-propelled system makes yard work genuinely effortless, and the 3-in-1 versatility covers all mowing preferences. The affordable price point combined with reliable performance makes it our top choice for most homeowners.
For those prioritizing cordless convenience, the Greenworks 80V Pro delivers professional results with zero emissions and remarkably quiet operation, earning our Best Multi-functional recommendation. The 4-in-1 system provides unmatched versatility, and the LED headlight extends your mowing flexibility.
Budget-conscious buyers will find excellent value in the MUTAOMAY 170cc Gas Mower, offering professional 170cc power at an accessible price with the added benefit of 7 height adjustment positions.
Consider your specific needs: property size, terrain type, storage constraints, and noise preferences. For properties up to half an acre, cordless options provide excellent convenience. For larger properties or demanding terrain, the power and runtime of gas models remain unmatched. Whatever your choice, any of these top recommendations will transform your lawn care routine.
- 21 inch self propelled lawn mower
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