RB 9" Small Lawn Mower for Small Spaces, 40V 2Ah vs WORX Nitro 21" Cordless Lawn Mower, Electric Mower
Updated July 2026 — WORX Nitro 21" Cordless Lawn Mower, Electric Mower leads on height and length.
The RB 9" Small Lawn Mower is ideal for small spaces and budget-conscious buyers, while the WORX Nitro 21" offers advanced features for larger lawns. Choose based on your lawn size and needs.
Why RB 9" Small Lawn Mower for Small Spaces, 40V 2Ah is better
Price
RB is $169.99, significantly cheaper than WORX at $359.99.
Weight
RB weighs only 11.5 lbs, making it easier to maneuver.
Storage
RB offers upright storage, saving up to 70% space.
Why WORX Nitro 21" Cordless Lawn Mower, Electric Mower is better
Cutting Width
WORX has a 21-inch cutting width compared to RB's 9 inches.
Power
WORX's brushless motor delivers 40% more power.
Battery Life
WORX provides a maximum runtime of 50 minutes with two batteries.
Overall score
Specifications
| Spec | RB 9" Small Lawn Mower for Small Spaces, 40V 2Ah | WORX Nitro 21" Cordless Lawn Mower, Electric Mower |
|---|---|---|
| Motor Speed | 6000 RPM | Brushless 2.0 |
| Cutting Heights | 3 | 7 |
| Self-Propelled | No | Yes |
| Runtime | N/A | 50 min |
| Safety Features | Tilt Stop | Intellicut |
Dimension comparison
Overview of the Products
When comparing the RB 9" Small Lawn Mower and the WORX Nitro 21" Cordless Lawn Mower, the key takeaway is their target user base. The RB mower is designed for small spaces, while the WORX mower caters to larger lawns. Priced at $169.99, the RB is about 53% cheaper than the WORX, which retails for $359.99. This price difference reflects their structural and functional capabilities tailored to different lawn sizes.
The RB mower's lightweight design and compact features make it ideal for tight corners and small yards. In contrast, the WORX mower’s self-propulsion and advanced technology are engineered for efficiency across larger areas, making it suitable for lawns of up to ½ acre. Thus, potential buyers should consider their lawn size and mowing needs when evaluating these options.
Design and Build Quality
The RB 9" Small Lawn Mower stands out with its ultra-lightweight design, weighing only 11.5 lbs without the battery, making it easy to maneuver around small yards. Its compact size also allows for convenient upright storage, saving up to 70% space. This design is perfect for those with limited storage options.
On the other hand, the WORX Nitro 21" Cordless Lawn Mower is designed for durability and efficiency. Its high-strength polymer deck is lightweight yet resistant to impact damage and corrosion, ensuring longer-lasting use. The 21-inch cutting width is significantly larger than the RB's 9 inches, making it better suited for spreading out the mowing workload across bigger lawns. The contrasting designs cater to distinct user needs—compact efficiency versus robust capability.
Performance and Power
In terms of performance, the RB mower features a high-speed 6000RPM brushless motor, which is powerful for its size, allowing for fine mulching suitable for small lawns up to 540 sq. ft. This efficiency is coupled with three adjustable cutting heights, enabling users to maintain their grass health easily.
Conversely, the WORX Nitro mower is equipped with a brushless motor 2.0 that delivers 40% more power than first-generation models and boasts a runtime of 50 minutes when using the included (2) 20V 5.0Ah batteries. This mower is designed for lawns up to ½ acre, providing a self-propelled feature that allows users to set their speed up to 3.7 MPH, making it easier to manage larger spaces. Therefore, the performance specifications reflect the intended use of each mower.
Cutting Versatility
The RB 9" Small Lawn Mower offers three cutting heights ranging from 1.2" to 2", allowing users to maintain a well-groomed lawn tailored to their preferences. This level of cutting versatility is suitable for smaller yards where precise adjustments can enhance overall lawn aesthetics.
In contrast, the WORX Nitro mower provides even greater flexibility with its 7-position single-lever height adjustment, ranging from 1.5" to 4". This mower supports multiple functionalities, including mulching, bagging, and rear side-discharging. This versatility is crucial for users managing larger lawns, where different grass types or conditions may require varied cutting approaches. Such differences make the WORX mower a more adaptable option for diverse mowing tasks.
Safety Features
Safety is paramount in lawn care equipment, and both mowers incorporate essential safety features. The RB mower has an advanced safety design that automatically stops the motor if tilted beyond 20° to 70°, ensuring user safety during operation. This feature is particularly beneficial for novice users or those unfamiliar with mowing.
On the other hand, the WORX Nitro mower includes patented Intellicut technology, which automatically adjusts the motor speed based on grass density, ensuring optimal power usage and safety during operation. Both models provide essential safety features, but the WORX mower's technology adds an extra layer of protection and efficiency, particularly for larger and potentially more hazardous mowing areas.
Storage and Portability
When it comes to storage and portability, the RB 9" Small Lawn Mower excels with its lightweight design and upright storage capability, which allows it to fit into tight spaces easily. The detachable aluminum handle further enhances its portability, making it ideal for users with limited storage options.
In contrast, the WORX Nitro mower features a fully collapsible handle for vertical storage, which is also space-saving. However, it is inherently bulkier due to its size and design aimed at handling larger lawns. While both mowers offer convenient storage solutions, the RB mower is more suited for those who prioritize portability and compactness, while the WORX caters to users who may have a bit more room and need a robust machine.
Battery Life and Charging
The battery systems of both mowers reflect their intended use. The RB 9" mower is powered by a 40V 2Ah battery, making it effective for small lawns but with limited runtime suited for its size. Users can expect decent performance for smaller areas but may find the battery life restrictive for extended use.
On the other hand, the WORX Nitro mower comes equipped with two 20V 5.0Ah PowerShare Pro batteries, providing a maximum no-load runtime of 50 minutes. This extended battery capacity is essential for tackling larger lawns, ensuring that users can complete their mowing tasks without frequent interruptions for recharging. Hence, the WORX mower clearly offers superior battery life and charging efficiency for larger mowing jobs.
Which should you buy?
Deciding between the RB 9" Small Lawn Mower and the WORX Nitro 21" Cordless Lawn Mower largely depends on your lawn size and specific needs. The RB mower is an excellent choice for small spaces, offering a compact design and a lower price point at $169.99—about 53% less than the WORX mower. It is lightweight and easy to maneuver, making it perfect for beginners or those with limited storage.
In contrast, the WORX Nitro mower, priced at $359.99, is built for larger lawns, featuring advanced technology like Intellicut and a self-propelled function for ease of use. With its robust design and enhanced battery life, it caters to users who require a more powerful mower for bigger spaces.
Ultimately, if you have a small yard, the RB mower is your best bet; however, for larger lawns requiring consistent performance and versatility, the WORX Nitro is the superior option.

