Mowers
Best electric mower for hills and slopes
On a gradient you are lifting the whole mower on every uphill pass. Two published specs decide how that goes.
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We have not tested these units. Every spec on this page comes from the manufacturer's own documentation and is linked to it. Every computed figure is arithmetic you can redo. Prices are checked daily — last verified January 1, 1970. Here is exactly how we pick.
Quick picks
Ranked on the published specs and the arithmetic below. Tap any row to jump to the full write-up. We have not tested these units -- here is exactly how we pick.
| # | Product | Best for | Score | Price |
|---|---|---|---|---|
| 1 | No photo Kobalt 80V Max 21" Self-Propelled (dual-port) Two 4Ah bays, 80 published minutes and an acre rating -- the most runtime per purchase of any 80V walk-behind here. | Best two-bay runtime | 8.4 | |
| 2 | No photo EGO Power+ 21" Select Cut LM2135SP The most watt-hours in the box of any flagship walk-behind here, on the platform with the widest tool range to grow into. | Best overall | 9.1 | |
| 3 | No photo Toro 60V Max 21" Recycler Self-Propel (21356) The only manufacturer here that publishes the actual watt-hour figure for its pack -- and the number tells you something the others hide. | Best published watt-hour honesty | 8.3 | |
| 4 | No photo Ryobi 40V HP Brushless 21" Self-Propelled Two 6Ah packs and the longest published runtime claim on this page, on the platform with the cheapest route to a fourth and fifth tool. | Best for a household already on Ryobi | 8.6 |
#ad Buy links are affiliate links. Prices come from a live daily check; where we have no verified price we say "check price" rather than print a stale one.
We should say this before the ranking: no manufacturer on this page publishes a maximum slope rating for a walk-behind mower, and we have not mowed a hill with any of them. So this is a ranking of drive specifications, which is a real and useful thing, and it is not a test of gradient performance, which we cannot offer.
What actually decides slope performance
| Factor | Published? | Why it matters on a gradient |
|---|---|---|
| Drive speed control | Partly | On a slope you want the mower matching your pace exactly. A fixed-speed drive that outruns you uphill is worse than no drive. |
| Drive type (RWD/FWD/AWD) | Yes | Weight transfers rearward going uphill, so rear-wheel drive gains traction where it is needed. |
| Weight | Rarely | You are lifting it on every uphill pass. Three of six brands do not publish this. |
| Maximum slope rating | No | Not published by any walk-behind manufacturer here. |
| Wheel size and tread | No | Not published in any spec sheet we found. |
| Deck balance and center of gravity | No | Never published, and genuinely only assessable hands-on. |
Three of those six factors are not published by anyone. That is why this category is written in adjectives everywhere else — and it is why, if slope is your main problem, you should read a publisher who genuinely pushed these machines up a bank as well as reading this page.
The drive specs, compared
| Mower | Drive | Speed control | Weight |
|---|---|---|---|
| Kobalt 80V SP | RWD | 7 speed settings | Not published |
| EGO LM2135SP | RWD | 0.9-3.1 MPH variable | Not published |
| Toro 21356 | RWD, Personal Pace | Pressure-sensitive variable | 66 lb |
| Ryobi 40V HP | RWD | Variable, range not published | Not published |
| Greenworks LM2108S | RWD | Variable, range not published | 75 lb |
From each manufacturer's product page, checked 3 September 2026.
Notes on the picks
Kobalt: seven discrete speeds
Seven published speed settings is the most granular drive control in the group. On a slope, where your comfortable pace uphill and downhill differ substantially, being able to pick a setting rather than modulate a trigger is a genuine advantage. It also carries 640Wh, which matters because slope work raises current draw.
EGO: the published speed range
EGO is the only brand that publishes an actual speed range: 0.9 to 3.1 MPH. The bottom of that range is the important half — 0.9 MPH is a genuinely slow crawl, which is what you want traversing a bank. Ryobi and Greenworks both say "variable" without telling you the limits, so we cannot confirm they go as slow.
Toro: pressure-sensitive drive, and a published weight
Personal Pace varies drive speed with how hard you press the handle, which on undulating ground means you are not constantly adjusting a setting. Toro is also one of only two brands here that publishes a weight, at 66 lb — the lightest self-propelled figure available to us.
Ryobi: the runtime headroom
Slope work costs watt-hours: the drive motor works harder uphill and you mow more slowly, so a lawn takes longer. Ryobi's 480Wh across two packs and its 6.0Wh-per-minute figure give the most margin for that of any 40V option here.
The one published slope figure we found
Across every product page we read for this site, exactly one manufacturer publishes a maximum gradient: Segway rates the Navimow i105N robot mower at 16 degrees. That is not directly transferable to a walk-behind — a robot mower has no operator to provide traction or judgment — but it is a useful anchor for what a small wheeled machine on grass can manage, and it is worth knowing if you were considering letting a robot handle the bank.
Safety, which is not a spec
- Mow across a slope with a walk-behind, not up and down. A slip going uphill can pull the mower back toward you.
- Riding mowers reverse this rule — they are generally driven up and down slopes, not across, because of rollover risk. Follow the manual for your machine.
- Wet grass on a slope is a different job. Traction drops for both you and the mower.
- Above a certain gradient nothing wheeled is appropriate. A string trimmer on a steep bank is safer than any mower — see the trimmer roundup.
The picks in full
Specs are the manufacturer's own and linked to the page they came from. Prices come from a live daily check; where we have no verified price we say so rather than print a stale one.
Kobalt 80V Max 21" Self-Propelled (dual-port)
Kobalt · Kobalt 80V Max · Our score 8.4/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
Two 4Ah bays, 80 published minutes and an acre rating -- the most runtime per purchase of any 80V walk-behind here.
Published specs
| Deck | 21 in, steel |
|---|---|
| Motor | Brushless |
| Batteries included | 2 x 80V 4.0Ah (dual port) |
| Runtime claim | Up to 80 min |
| Rated for | Up to 1 acre |
| Drive | Self-propelled RWD, 7 speed settings |
| Recharge | Approx. 60-90 min |
Source: Kobalt 80-Volt 21-in Self-propelled Battery Mower (2 batteries), lowes.com
80V x 4.0Ah = 320Wh per pack; two bays = 640Wh installed. Kobalt's listing does not state whether the two ports discharge simultaneously or in sequence, so we do not claim either -- what is verifiable is that 640Wh is on the machine when you start.
What the numbers favor
- 640Wh installed across two bays, the most of any walk-behind on this page
- Rated to 1 acre, twice the Greenworks 80V flagship's half-acre rating
- Seven published speed settings on the self-propel drive
- All Kobalt 80V packs are cross-compatible across the 80V outdoor line
What they don't
- Sold through Lowe's only, so availability and price track one retailer
- The listing does not publish weight, cut-height range or a noise figure
- Kobalt's 80V outdoor range is narrower than EGO's or Ryobi's
you want a platform rather than a mower. Kobalt is a single-retailer house brand -- fine for the tool, thinner as a decade-long ecosystem bet.
How it scores
Scores are our editorial weighting of the published specs above, not a test result. They are deliberately kept out of this page's structured data.
EGO Power+ 21" Select Cut LM2135SP
EGO · EGO 56V ARC Lithium · Our score 9.1/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
The most watt-hours in the box of any flagship walk-behind here, on the platform with the widest tool range to grow into.
Published specs
| Deck | 21 in |
|---|---|
| Cutting torque | Up to 7.0 ft-lbs |
| Battery included | 56V 7.5Ah |
| Cut height | 1-4 in, 8 positions |
| Self-propel speed | 0.9-3.1 MPH |
| Runtime claim | Up to 60 min |
| Warranty | 5-yr tool / 3-yr battery |
Source: EGO POWER+ 21" Select Cut System (LM2135SP), egopowerplus.com
56V x 7.5Ah = 420Wh, using EGO's advertised pack voltage.
What the numbers favor
- 420Wh in the box -- the largest included pack of any flagship walk-behind on this page
- Eight cut-height positions from 1 to 4 in, the widest published range here
- Three interchangeable lower blades (mulching, high-lift bagging, extended runtime)
- 5-year tool warranty, the longest published on this page
What they don't
- EGO publishes torque (7.0 ft-lbs), not motor wattage, so it cannot be compared directly against Greenworks' 1500W figure
- The 7.5Ah pack that earns the runtime claim is also the expensive one to replace
your yard is under a quarter acre. You would be paying for 420Wh of headroom you will never discharge, and a 20 in push mower cuts the same grass.
How it scores
Scores are our editorial weighting of the published specs above, not a test result. They are deliberately kept out of this page's structured data.
Toro 60V Max 21" Recycler Self-Propel (21356)
Toro · Toro 60V Max Flex-Force · Our score 8.3/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
The only manufacturer here that publishes the actual watt-hour figure for its pack -- and the number tells you something the others hide.
Published specs
| Model | 21356 |
|---|---|
| Deck | 21 in, 14-gauge steel |
| Battery | 60V Max L324, 6.0Ah, 324Wh |
| Charge time | 150 min |
| Runtime claim | Up to 45 min on the 6.0Ah |
| Drive | Personal Pace variable-speed RWD |
| Weight | 66 lb |
| Storage | SmartStow vertical |
Source: 60V Max 21 in. Recycler Self-Propel Lawn Mower (21356T), toro.com
Toro labels the pack 60V Max 6.0Ah and publishes 324Wh. 324 / 6.0 = 54V -- the nominal voltage, not the 60V max-charge figure on the sticker. Every brand's 'max volts' is roughly 11% above nominal, so a nameplate watt-hour number is always about 11% optimistic. This is the single most useful spec on this page.
What the numbers favor
- Publishes a real watt-hour figure (324Wh) instead of leaving you to multiply the marketing voltage
- 45 minutes from 324Wh, against Greenworks' 33 minutes from a nameplate 320Wh
- 14-gauge steel deck, the only steel deck spec published on this page
- SmartStow vertical storage -- a genuine constraint solver in a one-car garage
What they don't
- 150-minute recharge is the slowest here by a wide margin
- Toro's 60V line is narrower than EGO's or Ryobi's, so the platform grows less far
you are buying into a platform rather than a mower. Toro builds excellent mowers; the 60V Flex-Force tool range is not the one to bet a decade of yard tools on.
How it scores
Scores are our editorial weighting of the published specs above, not a test result. They are deliberately kept out of this page's structured data.
Ryobi 40V HP Brushless 21" Self-Propelled
Ryobi · Ryobi 40V · Our score 8.6/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
Two 6Ah packs and the longest published runtime claim on this page, on the platform with the cheapest route to a fourth and fifth tool.
Published specs
| Model | RY40HPLM01B |
|---|---|
| Deck | 21 in |
| Motor | Brushless, 40V HP |
| Batteries included (kit) | 2 x 40V 6.0Ah |
| Drive | Variable-speed rear-wheel self-propel |
| Runtime claim | Up to 80 min on 2 x 6Ah |
Source: 40V HP Brushless 21" Self-Propelled Mower, ryobitools.com
40V x 6.0Ah = 240Wh per pack; the kit ships two, so 480Wh total -- but only 240Wh is available at any moment, because the mower draws one pack at a time.
What the numbers favor
- 480Wh across two packs, the most total energy in any kit here
- Two packs means you swap and keep mowing instead of waiting on a charger
- Ryobi's 40V range is the broadest consumer battery line of the three platforms
What they don't
- Only one 240Wh pack is live at a time -- the 480Wh is sequential, not simultaneous
- Ryobi does not publish a cut-height range or weight on the product page, so both are unknown to us
you own nothing on Ryobi yet and expect to buy heavy tools later. 40V is the lowest voltage of the three platforms, and the ceiling shows on chainsaws and riding gear.
How it scores
Scores are our editorial weighting of the published specs above, not a test result. They are deliberately kept out of this page's structured data.
Common questions
What is the best electric mower for a steep hill?
Do I need self-propelled for a sloped lawn?
What slope is too steep to mow with a walk-behind?
Is rear-wheel drive better on hills?
Should I mow across a slope or up and down?
Sources
- Kobalt 80-Volt 21-in Self-propelled Battery Mower, lowes.com
- EGO POWER+ 21" Select Cut System (LM2135SP), egopowerplus.com
- Toro 60V Max 21 in. Recycler Self-Propel Lawn Mower (21356T), toro.com
- RYOBI 40V HP Brushless 21" Self-Propelled Mower, ryobitools.com
- Greenworks 80V 21" 4-in-1 Self-Propelled Mower (LM2108S), greenworkstools.com
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