How we test and score

Every model carries a score out of 100, built from nine dimensions weighted by how much they matter to an owner over a season.

The nine dimensions

• Mapping reliability — how consistently it holds a boundary across a full season
• Slope performance — rated slope against real behaviour on damp grass
• Obstacle avoidance — object classes recognised and what it does when confused
• Cut quality — deck width, height range and finish on both cool- and warm-season grass
• Build and weather resistance — IP rating, materials, how it survives winter
• App and software — setup time, zone handling, update record
• Support and parts — availability of blades and batteries in the US and Canada
• Security — anti-theft hardware, tracking, what happens when it is lifted
• Value — area covered and capability per dollar at list price

What we will not do

We do not accept payment for a score, a ranking or a place in a list. Affiliate commission is earned on some outgoing links, and it is identical whichever machine you buy, so it cannot move a ranking.

Where a specification is disputed between two of a manufacturer's own pages, we publish the conflict rather than pick the flattering number.