Riding & Robot Mowers
What does a robot mower cost to run?
Not one maker publishes the battery capacity, so nobody can compute the electricity exactly. Here is the ceiling, and the cost that actually matters.
Affiliate disclosure: we earn a commission if you buy through our links, at no extra cost to you. It never changes which product we rank first — here is how we're funded.
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.
"What does it cost to run?" is a fair question with an unsatisfying answer. Every robot mower maker publishes run times, and not one publishes the battery capacity that would turn those minutes into kilowatt-hours. So this page does the next most useful thing: it puts a bound on the number and names the costs that are actually worth budgeting for.
The short answer
The specification nobody publishes
To compute energy you need capacity. Here is what the three robots in our registry publish, and what they leave out.
| Figure | Navimow i105N | Automower 450XH | Automower 435X AWD |
|---|---|---|---|
| Run time per charge | 60 min | 270 min | 145 min |
| Charge time | 90 min | Not published | Not published |
| Battery capacity (Wh) | Not published | Not published | Not published |
| Charger input rating | Not published | Not published | Not published |
| Energy per charge | Not computable | Not computable | Not computable |
| Working area | Up to 1/8 acre | 1.25 acre | 0.9 acre (+/-20%) |
Transcribed from the Navimow i105N, Automower 450XH and 435X AWD product pages.
What we can say: the walk-behind comparison
Two independent acreage ratings — Greenworks at 320Wh for half an acre, Kobalt at 640Wh for a full one — put a cordless walk-behind at about 640 watt-hours per acre. That is a real, published anchor, and it bounds the discussion.
Even if a robot used ten times the energy of a walk-behind across a season — and nothing published lets us say whether it does — the electricity would still be a small number. The purchase price dominates this decision, which is what our is a robot mower worth it page is really about.
The costs that actually matter
- Blades. Robots use small pivoting razor blades rather than one big steel blade, and they are consumables. Husqvarna publishes three pivoting razor blades on the 450XH; neither maker publishes a replacement interval, so budget for them without being able to plan them.
- The boundary wire, if there is one. Aeration, edging and digging all cut wire. A wire-free machine removes this cost entirely — see wire-free robot mowers.
- Winter storage. Both Husqvarnas and the Navimow are light enough to carry indoors; what nobody publishes is a storage temperature range for the pack.
- Your time, saved. The entire value proposition is that the mowing stops being a task. Our DIY vs hiring a service page prices the alternative.
The three machines this applies to
The Navimow i105N publishes the most: 60 minutes of running against 90 minutes of charging, 58 dB(A), 24 lb, and up to an eighth of an acre.
#ad Check the Segway Navimow i105N Robot Mower price on Amazon — how we're funded.
The Automower 450XH covers the most ground — 1.25 acres on 270 minutes per charge — and publishes neither a charge time nor a capacity.
#ad Check the Husqvarna Automower 450XH price on Amazon — how we're funded.
The 435X AWD trades area for traction: 0.9 acre, 145 minutes, and a 70% slope limit.
#ad Check the Husqvarna Automower 435X AWD price on Amazon — how we're funded.
What we cannot tell you
We have not metered any of these machines. No maker publishes a battery capacity, a charger input rating, a standby draw or a blade replacement interval, and standby draw matters here because a robot sits on its dock most of the day. Any monthly cost figure you see for a robot mower — including from us, if we printed one — would be an estimate dressed as a specification, and we will not do that.
The products discussed
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.
Segway Navimow i105N Robot Mower
Segway · Navimow (self-contained) · Our score 8.0/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
No perimeter wire, 58 dB published, and an eighth of an acre it will cut while you are at work.
Published specs
| Coverage | Up to 1/8 acre |
|---|---|
| Cutting width | 7.1 in |
| Cut height | 2-3.6 in |
| Runtime / charge | 60 min run / 90 min charge |
| Navigation | RTK + Vision, wire-free |
| Max slope | 16 degrees |
| Noise | 58 dB(A) |
| Weight | 24 lb |
Source: Navimow i105N, navimow.com
60 minutes of run against 90 minutes of charge is a 60/150 duty cycle -- about 40%. Over a 12-hour window that is roughly 4.8 hours of actual cutting, which is the number that decides whether 1/8 acre is realistic for your grass growth rate.
What the numbers favor
- No perimeter wire to bury, cut or repair -- boundaries are set in the app
- 58 dB published, quiet enough to run while people are outside
- Publishes both runtime and charge time, so the duty cycle is computable
- 24 lb, light enough to carry to storage single-handed
What they don't
- 1/8 acre is a genuinely small lawn; Segway's own 0.15 acre figure is layout-dependent
- 7.1 in cutting width means many passes
- 16 degree maximum slope rules out a lot of real gardens
your lawn has slopes over 16 degrees or is over an eighth of an acre. Both are hard published limits, not soft ones.
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.
Husqvarna Automower 450XH
Husqvarna · Automower (self-contained) · 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.
An acre and a quarter at a 45% slope limit, with 270 minutes of mowing between charges.
Published specs
| Max working area | 1.25 acre |
|---|---|
| Max slope, inside | 45% |
| Max slope, at boundary | 15% |
| Cutting width | 9.45 in |
| Blades | 3 pivoting razor blades |
| Mow time per charge | 270 min |
| Boundary | Wire, with Follow guide |
| Security | GPS theft tracking |
| Weight | 33.7 lb |
Source: Husqvarna Automower 450XH Robotic Lawn Mower, husqvarna.com
arctan(0.45) = 24.2 degrees. That is 8 degrees steeper than the Segway Navimow's published 16 degree limit and 11 degrees shallower than the AWD 435X's 35 degrees. The boundary figure matters just as much: 15% (8.5 degrees) is where the wire may run, which rules out installations whose perimeter climbs the bank even if the lawn inside it is within limits.
What the numbers favor
- 1.25 acre, the largest published working area here
- 270 min of mowing per charge, nearly double the AWD model
- 9.45 in cutting width, the widest of the three robots we hold
- GPS theft tracking on a machine that lives outdoors
What they don't
- 15% maximum slope at the boundary is a hard constraint on where the wire can run
- Cutting height range is not published on the product page
- Two-wheel drive, so 45% is the ceiling however good the tires are
your perimeter itself is steep. The boundary limit is 15%, and no amount of lawn-side capability changes it.
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.
Husqvarna Automower 435X AWD
Husqvarna · Automower (self-contained) · Our score 8.7/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
A published 70% slope limit inside the work area -- 35 degrees, the steepest figure any maker prints for a robot.
Published specs
| Max working area | 0.9 acre (+/-20%) |
|---|---|
| Max slope, inside | 70% (35 degrees) |
| Max slope, at boundary | 50% |
| Cutting width | 8.7 in |
| Cut height | 1.2-2.8 in |
| Mow time per charge | 145 min |
| Drive | All-wheel drive, pivoting rear body |
| Boundary | Physical wire |
| Weight | 39 lb |
Source: Husqvarna Automower 435X AWD, husqvarna.com
A percentage grade is rise over run, so 70% is arctan(0.70) = 35.0 degrees -- which matches Husqvarna's own stated 35 degrees exactly. Worth converting because makers do not agree on units: Segway publishes 16 degrees for the Navimow, which is arctan of 0.287, or a 29% grade. Same quantity, two conventions, and a factor-of-two difference in what the machines will climb.
What the numbers favor
- 70% inside the work area, the highest published slope figure in our registry
- All-wheel drive with a pivoting body to keep all four wheels loaded
- Publishes separate limits for slopes at the boundary (50%) and inside it (70%)
- Cut height range published, 1.2 to 2.8 in
What they don't
- 0.9 acre maximum, less than the flat-ground 450XH
- 145 min per charge, roughly half the 450XH's mow time
- Boundary wire must be buried or pegged -- no wire-free option
- 39 lb, the heaviest robot we hold specs for
your lawn is flat. AWD costs runtime and money for traction you will never call 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.
Where to buy the tools on this page
Every link below is an Amazon affiliate link. We show no price we have not verified today, so where there is no live figure the link says "check price" and takes you to the listing to read it there.
Best wire-free robot for a small lawn
Segway Navimow i105N Robot Mower
Segway · Navimow (self-contained)
Best for big sloped lawns
Husqvarna Automower 450XH
Husqvarna · Automower (self-contained)
Best for steep slopes
Husqvarna Automower 435X AWD
Husqvarna · Automower (self-contained)
#ad As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. How we're funded.
Common questions
How much electricity does a robot mower use?
Is a robot mower expensive to run?
What are the real running costs of a robot mower?
Do robot mowers use more electricity than a regular mower?
How much does it cost to run a robot mower per month?
Sources
Read next
- Riding & Robot Mowers
Above an acre the question stops being which mower and starts being how many watt-hours.
- Is a robot mower worth it?
The hours-per-season arithmetic, and the published limits that decide it before price does.
- Best robot lawn mower (and the limits nobody puts on the box)
Coverage, slope limit and duty cycle -- the three published numbers that decide if a robot mower fits.
- Best robot mower for a small yard
Working area, duty cycle and noise for a small lawn, against the machine built for ten times the ground.
- What does it cost to charge a cordless yard kit?
A mower charge is 0.42 kWh. The season arithmetic at the EIA published average rate.
- DIY lawn care or hire a service: which should you actually do?
The trade is hours, not money. The DIY kit, the season's hours, and what a service is better at.