Quick Answer: Robot mower cutting height ranges vary by brand from as narrow as 20–60mm (0.8–2.4 in) on entry-level boundary-wire models to a full 1–4 inches on flagship wire-free machines like the Segway Navimow X430 and Husqvarna’s iQ series. The right height depends on your grass type — roughly 2.5–3.5 inches for cool-season lawns, 1.5–2.5 inches for warm-season grass — and should follow the one-third rule: never remove more than a third of the blade’s height in one cut, per UC ANR’s Integrated Pest Management program. Because robot mowers cut daily instead of weekly, they naturally stay closer to that rule than a traditional mower ever does, which is the main reason robotically-mowed lawns often come out denser and healthier.
Cutting height shows up in nearly every robot mower spec sheet and nearly every review, but almost none of them explain what the range actually means for your lawn or how to pick a number. Below, we pull the real adjustment ranges from ten current brands’ own documentation, explain the one-third rule that should drive your setting, and cover how (and how often) to change it.
The one-third rule, and why robot mowers are good at it
Turf-extension programs have used the same guideline for decades: never remove more than one-third of the grass blade’s height in a single mow. Per the University of California’s Integrated Pest Management (UC ANR IPM) program, “no more than one-third of the grass blades should be cut at a time” — cut more than that in one pass and the plant can stop root growth while it recovers the lost leaf area, leaving the lawn thinner and more vulnerable to weeds and disease. A traditional once-a-week mow routinely blows past that limit during a fast-growing spring stretch, which is exactly the stress the rule is meant to prevent.
Robot mowers sidestep the problem almost by accident. Because they run on a near-daily schedule instead of a weekly one, each individual pass removes only a sliver of growth — well inside the one-third threshold even during peak growing season. That’s also the finding behind a 2026 University of Florida IFAS study (turf researcher Bryan Unruh) covered in our robot mower for St. Augustine grass guide: daily robotic mowing produced denser, healthier turf than conventional weekly mowing, even at a shorter cutting height than usually recommended for that grass. Frequency, not just the height number, is what keeps the lawn healthy.
Cutting height range by brand
| Brand / model | Cutting height range | Adjustment method |
|---|---|---|
| Segway Navimow X430 | 0.75–4 in (19–102mm) | App, per zone |
| Husqvarna iQ series (420 iQ+) | 1–4 in (25–102mm) | App |
| Gardena Sileno | 1–4 in (25–102mm) | App / dial |
| Mammotion Luba 2 H-series | 2.2–4 in (56–102mm) | App, per zone |
| Segway Navimow i110N | 2.0–3.6 in (51–91mm) | App |
| Mammotion Luba 2 S-series | 1–2.7 in (25–69mm) | App, per zone |
| Robomow (current lineup) | 0.8–3.4 in (20–86mm) | App / manual dial |
| EcoFlow Blade | 0.8–3.0 in (20–76mm) | App |
| Anthbot Genie | 1.2–2.8 in (30–70mm) | App |
| Redback (MowRo) | 1–2.5 in (25–64mm) | Manual dial |
| Makita RM350D | 0.8–2.4 in (20–60mm), 5mm steps | Manual dial |
| Husqvarna Automower 115H | Up to ~2.4 in (60mm) | App |
Ranges per each manufacturer's own product documentation; verify the current spec for your exact model before buying, since firmware and hardware revisions can shift them.
A few patterns fall out of that table. Entry-level and older boundary-wire models tend to cap out around 2–2.4 inches — fine for cool-season lawns kept short, but too low a ceiling for St. Augustine, centipede, or any warm-season grass that wants to stay above 2.5 inches. Flagship wire-free RTK models from Segway, Husqvarna, and Mammotion’s H-series push the top end to 4 inches, wide enough to cover almost any grass type or seasonal preference. If you already know your grass needs a taller cut, check the maximum cutting height before anything else on the spec sheet — it’s a harder disqualifier than slope rating or coverage acreage for the wrong lawn.
Segway Navimow X430
- Widest cutting height range in this comparison, tied with Husqvarna's iQ series.
- Set height independently per mapped zone — useful if your front and back yards run different grass types.
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Husqvarna Automower (iQ Series)
- Full 1–4 inch range covers nearly every cool- and warm-season grass type without an accessory kit.
- Height is set per work area in the app — see our [robot mower app guide](/guides/robot-mower-app-explained/) for how zone-level settings work.
How and when to change it
Raise the cutting height for the first mow on a new install, then lower it in small steps over a week or two rather than dropping straight to your target — the same one-third-rule logic applies to a mower meeting an overgrown or newly-seeded lawn for the first time, not just week-to-week maintenance. Our robot lawn mower installation guide covers this alongside the rest of first-run setup. Beyond the initial install, most owners set a height once per season and leave it — raise it slightly heading into a hot, dry summer stretch (taller grass shades its own roots and needs less water) and lower it again in cooler, wetter weeks when growth is faster and thicker.
The bottom line
Cutting height is one of the few robot mower specs that’s genuinely make-or-break for a specific lawn, not just a nice-to-have — a model that tops out at 2.4 inches will scalp a St. Augustine or centipede lawn no matter how good its navigation is. Check the full range, not just a headline number, match it to your grass type, and let the one-third rule (helped along by the mower’s own near-daily schedule) do the rest of the work. For picks organized by yard size and terrain rather than cutting height alone, see our best robot lawn mower guide, and if you’re mowing St. Augustine or another warm-season grass specifically, our robot mower for St. Augustine grass guide goes deeper on that match-up.