6 Best 21-Inch Self-Propelled Lawn Mowers of 2025

This high-torque brushless motor sets the Greenworks 80V apart from the pack—delivering gas-like cutting power without the noise, fumes, or maintenance. With a 21-inch steel deck and self-propelled rear-wheel drive, it slices through thick grass with authority, while the variable speed control lets you adapt to slopes and lawn conditions seamlessly. For homeowners tired of gas hassles and underpowered corded mowers, this machine delivers a perfect balance of performance, quiet operation, and eco-friendly efficiency—making it ideal for half-acre lots and beyond.

In real-world use, the mower consistently handled tall, damp grass without bogging down, thanks to its robust motor and optimized blade airflow. The included 4.0Ah battery provided up to 45 minutes of runtime on a mixed-height lawn, which is more than enough for most suburban yards. The LED headlights were a standout, enabling early morning mowing without disturbing the neighborhood—thanks to its 3x quieter operation than gas models. While it struggles slightly on wet grass (as most electric mowers do), the 4-in-1 versatility—especially the turbo leaf pickup mode—adds serious seasonal value beyond just grass cutting.

When stacked against the PowerSmart gas models, the Greenworks 80V trades unlimited runtime for cleaner, quieter, and smarter operation—a worthy trade for eco-conscious users. Compared to the 60V Greenworks model, it offers higher voltage for improved torque and longer motor life, making it the top-tier pick for those who want the best cordless performance. It’s not the cheapest, but for users seeking cutting-edge electric power with zero emissions and minimal upkeep, this is the gold standard. It outperforms most gas mowers under half an acre while being far easier to live with day to day.

The PowerSmart 21-inch gas mower earns its “Best Budget Friendly” title with a reliable Briggs & Stratton 140cc engine that fires up smoothly and powers through thick grass without hesitation. Its 21-inch steel deck and rear-wheel drive deliver solid traction and wide cutting swaths, drastically reducing mowing time on medium to large lawns. For homeowners who want no-nonsense reliability at a wallet-friendly price, this mower delivers real gas-powered performance without premium branding markups.

During testing, the mower excelled on dry, overgrown grass and maintained consistent speed on mild slopes, thanks to its 10-inch rear wheels and rear-wheel propulsion. The single-lever 6-position height adjustment made changing cut heights quick and uniform across all wheels. While it lacks LED lights or variable speed control, it offers solid 3-in-1 functionality—especially effective in mulching mode, where clippings were finely dispersed. However, it can struggle slightly on very tall, wet grass, and the 1.4-bushel bag fills quickly, requiring frequent emptying on larger lawns.

Compared to the pricier BILT HARD and Greenworks models, this PowerSmart sacrifices advanced features and engine power for essential performance at half the cost. It’s not as quiet or feature-rich as the 80V Greenworks, but it runs indefinitely with fuel—making it better for larger or irregularly mowed yards. It’s the ideal gateway mower for budget-focused buyers who still want self-propelled ease and dependable cutting. It may lack flash, but it outperforms its price tag with rugged simplicity and consistent results.

The Greenworks 60V strikes a sweet spot between power and practicality, offering brushless efficiency and true cordless freedom without the premium 80V price tag. With dual 4.0Ah batteries included, it delivers up to 45 minutes of continuous mowing—enough for most 1/3 to 1/2 acre lawns—while the rapid dual-port charger gets both batteries back to full in under an hour. The self-propelled rear-wheel drive makes it a joy to push uphill, and the LED headlights extend usable mowing hours into dusk.

In practice, the mower handled medium-height grass with ease and maintained strong blade speed even in slightly damp conditions. The 4-in-1 system worked flawlessly, particularly the mulching function, which left an almost invisible finish. Unlike lower-voltage electric mowers, the 60V brushless motor provided consistent torque, though it showed minor strain in very thick, tall patches. The ergonomic handle and foam grip reduced fatigue during longer sessions, and the quiet operation meant early mowing didn’t wake the neighbors. It’s not quite as powerful as the 80V model, but for most users, the difference is negligible.

Against the 80V Greenworks, this model trades a bit of raw power for better value and included battery redundancy—you get two batteries instead of one. Compared to the MightyMow 20V, it offers higher voltage, longer life, and superior integration with a full tool ecosystem. It’s perfect for homeowners who want a dependable, eco-friendly mower with expandable cordless tools. It delivers nearly top-tier performance at a more accessible entry point, making it the smartest mid-range investment.

When it comes to raw power and large-yard capability, the BILT HARD 21-inch mower stands tall with its 201cc OHV engine producing 9.0 ft·lb of torque—a serious upgrade over typical 140cc models. This extra muscle translates to effortless cutting through tall, wet, or dense grass, making it a top contender for half-acre+ lawns. The 8-position height adjustment offers surgical precision, from 1.2″ for short summer cuts to 3.75″ for lush spring growth, all adjusted via a single-lever system that keeps all wheels aligned.

On testing, the mower powered through uneven terrain and sloped yards with confidence, thanks to its reliable rear-wheel drive and sturdy build. The 3-in-1 deck performed well in all modes, especially side discharge, which cleared clippings efficiently even at full throttle. The no-choke, no-primer start system ensured reliable ignition every time—no tugging or priming required. While heavier than electric options, the foam-wrapped handle reduced vibration and fatigue during extended use. It’s not the quietest or cleanest option, but for serious mowing volume, it’s hard to beat.

Compared to the PowerSmart B&S model, the BILT HARD offers significantly more engine power and finer height control, making it better suited for larger, demanding yards. It doesn’t have LED lights or battery ecosystems, but it doesn’t need them—its focus is on brute reliability and cutting performance. It’s the best choice for homeowners who prioritize power and durability over convenience features. It costs more than budget gas mowers, but delivers premium performance that justifies the investment for large-lawn owners.

Built for dependability above all, the PowerSmart with Briggs & Stratton 140cc engine earns its “Best for Reliability” label with consistent starts and unflinching performance in tough conditions. Whether tackling damp morning grass or overgrown patches, the 140cc engine maintains steady RPMs without stalling, a testament to its engineering. The 21-inch steel deck and rear-wheel drive ensure broad, clean cuts and strong traction on slopes, while the 10-inch rear wheels roll smoothly over ruts and uneven ground.

In real-world use, this mower proved to be a workhorse for medium-sized lawns, delivering clean mulching and reliable bagging with minimal clogging. The single-lever 6-position height adjustment made on-the-fly changes simple and uniform. While it lacks advanced features like variable speed or LED lighting, it doesn’t need them—its simplicity is its strength. It starts every time, runs all day on gas, and requires only basic maintenance. The only real limitation is the modest 1.4-bushel bag, which needs frequent emptying on larger lawns.

Compared to the BILT HARD, it has less engine power but matches it in durability and ease of use. Against the Greenworks cordless models, it wins on uninterrupted runtime and all-weather resilience, though it’s louder and requires more upkeep. It’s the go-to choice for users who want a no-fail mower that just works, year after year. It may not impress with features, but it earns trust through rock-solid performance and minimal downtime.

The MightyMow redefines ease of use in cordless mowing with a dual 20V system that delivers up to 60 minutes of self-propelled runtime—an exceptional value for the price. Its brushless motor spins at 3100 RPM, generating strong suction for efficient clipping collection, while the 6-position single-lever height adjustment makes customization fast and intuitive. The self-propelled function adjusts from 2.0 to 4.3 ft/s, letting you stroll through the yard without pushing—ideal for older users or those with physical limitations.

In testing, the mower handled dry, medium-height grass with ease and maintained consistent speed on gentle slopes. The dual 8.0Ah batteries provide outstanding runtime, outlasting many higher-voltage competitors on a single charge. The 3-in-1 system worked reliably, though mulching was slightly less refined than premium models. One surprise was the boosted return airflow, which improved bag filling efficiency. However, performance dipped in tall or wet grass, and the plastic housing feels less durable than steel-deck rivals—a trade-off for its lighter weight.

Against the Greenworks 60V, it offers longer battery life at a lower price, but sacrifices voltage and long-term motor durability. Compared to gas mowers, it wins on quietness and zero maintenance, though it can’t match their raw power. It’s best suited for small to medium lawns where convenience and affordability are top priorities. It delivers the most battery bang for the buck, making effortless mowing accessible without breaking the bank.