Mowers
Best electric mower for a half acre to an acre
Past half an acre the question stops being which mower and becomes how many watt-hours you can carry.
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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 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 | |
| 3 | 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 | |
| 4 | No photo Greenworks 80V 21" 4-in-1 LM2108S The only mower here that publishes motor wattage, blade RPM, weight and an acreage rating -- and the only one whose battery warranty matches its tool warranty. | Best published spec sheet | 8.4 |
#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.
At a quarter acre almost any battery mower works. At half an acre the field thins sharply, and at a full acre only two of the mowers we have specs for can honestly claim to finish the job. This page is about that cliff.
The runtime cliff, in numbers
Now compare those requirements against what these mowers actually carry.
| Mower | Energy aboard | Rated for | 1/2 acre? | 1 acre? |
|---|---|---|---|---|
| Kobalt 80V SP | 640Wh (2 x 320Wh) | 1 acre | Yes | Yes, per Kobalt |
| Ryobi 40V HP 21" | 480Wh (2 x 240Wh) | Not published | Yes | Second charge |
| EGO LM2135SP | 420Wh (1 pack) | Not published | Tight | No, not on one pack |
| Greenworks LM2108S | 320Wh (1 pack) | 1/2 acre | Only with a spare | No |
Acreage ratings are the manufacturers' own where published. Our margin math assumes ~7.5Wh/min for a self-propelled 21-inch deck, derived from the runtime claims on each product page.
The Greenworks case is the instructive one. Greenworks rates the LM2108S for half an acre and claims 33 minutes of runtime on the included pack. Both statements can be true at once, but only if you buy a second battery — the rating describes the mower's capability and the runtime describes what is in the box. Reading only one of them is how people end up stranded two thirds of the way down the lawn.
Why two packs beats one big one at this size
On a small lawn we argue the opposite. At half an acre and up the case reverses for three reasons that all follow from the same arithmetic.
- You need more total energy than any single consumer pack holds. The largest packs in these ranges are 7.5-10.0Ah; even 560Wh is short of a comfortable one-acre figure.
- A swap costs thirty seconds, a recharge costs 40 to 150 minutes. Greenworks publishes 40 minutes to recharge, Toro publishes 150. Neither is something you want in the middle of a lawn.
- Two packs each do a shallower discharge. Shallow cycles are gentler on lithium cells than deep ones, so the same total work spread over two packs is arguably kinder to both (the detail is here).
Notes on the picks
Kobalt takes this page, and did not take the main roundup
640Wh installed and a manufacturer acreage rating of one acre make it the strongest walk-behind here for a big lawn, plus seven published drive speeds for varying terrain. It ranks lower on our main mower roundup because that page weighs platform breadth, and Kobalt is a single-retailer house brand with a narrower outdoor range. For a large lawn specifically, that matters less than the watt-hours do.
Ryobi is the value answer
480Wh across two 6.0Ah packs, 80 published minutes, and the lowest per-minute draw of any 21-inch mower we have specs for at 6.0Wh. On a half acre it finishes with room to spare, and the 40V platform is the cheapest route to the trimmer and blower you will also need on a lawn that size.
Where the EGO stops being the answer
420Wh in one pack covers half an acre only just, on a good day, on dry grass. It has no headroom for a wet week or a fortnight of growth. If you are on EGO and your lawn is half an acre, buy a second 7.5Ah pack before you buy anything else — 840Wh across two packs makes it a genuinely capable large-lawn machine. Above that, EGO's real large-lawn answer is a different tool entirely.
When to stop buying walk-behinds
That is the real threshold, and it is about your afternoon rather than the battery. The electric riding mower page runs the watt-hours-per-acre math properly.
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.
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.
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.
Greenworks 80V 21" 4-in-1 LM2108S
Greenworks · Greenworks 80V · 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.
The only mower here that publishes motor wattage, blade RPM, weight and an acreage rating -- and the only one whose battery warranty matches its tool warranty.
Published specs
| Model / SKU | LM2108S / 2550402 |
|---|---|
| Deck | 21 in |
| Max blade speed | 3200 RPM |
| Battery included | 80V 4.0Ah |
| Cut height | 1.38-4.0 in, 7 positions |
| Runtime claim | Up to 33 min |
| Weight | 75 lb |
| Rated for | Up to 1/2 acre |
| Warranty | 4-yr tool / 4-yr battery |
Source: 80V 21" 4-in-1 Self-Propelled Lawn Mower (LM2108S), greenworkstools.com
80V x 4.0Ah = 320Wh, using Greenworks' advertised pack voltage.
What the numbers favor
- 4-year battery warranty -- a year longer than EGO's 3-year, on the component that fails first
- Publishes blade RPM, weight and acreage rating; the other two brands publish none of the three
- 40-minute recharge on the included charger, the fastest published here
- 4-in-1 deck adds turbo leaf pickup on top of mulch, bag and side discharge
What they don't
- 320Wh included, the least of the three flagships -- and the 33-minute runtime claim reflects that
- 75 lb is the only published weight here, and it is not light
you want one battery to finish a half-acre without a swap. Greenworks rates the mower for 1/2 acre but claims only 33 minutes on the included pack; those two numbers only reconcile if you buy a second battery.
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 1 acre?
How many watt-hours to mow half an acre?
Can a walk-behind battery mower really do an acre?
Is it better to have two batteries or one big one on a large lawn?
Does a wider deck help on a large lawn?
Sources
Read next
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- What size mower do I need for my yard?
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