Every walk-behind trencher gets a score from 0 to 100% built from four factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Trenchers are grouped by engine, name-brand (Kohler, Briggs & Stratton) and budget, and use the same scale in both groups.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per horsepower | 30% |
| Power | engine horsepower | 20% |
| Start | electric start instead of recoil only | 20% |
| Warranty | longest warranty on the machine or engine | 30% |
Where the numbers come from
Engine size and power, trench depth and width, chain, start type and warranty come from the Amazon listing, which repeats the maker’s copy, because these makers publish no spec sheet. Prices are checked at Amazon and the lowest price at a store the page links to is used. Weights on these listings look like shipping weights, so only a stated net weight is shown.
The factors
Value is the current price divided by the engine’s horsepower as the maker states it, on a log scale, so halving the price per horsepower always counts the same. $350 per hp scores zero and $100 full marks.
Power is the maker’s stated engine horsepower: 12 hp scores zero and 16 hp full marks. Every trencher here is rated 14 or 15 hp, so this factor separates models by a point or two.
Start scores full marks for electric start and zero for recoil only.
Warranty is the longest warranty on the machine or its engine: 1 year scores zero and 3 years full marks. Only the Kohler engine models state more than a year.
What isn’t scored
Trench depth and width, chain length, tooth count, depth stops, side auger and weight are listed but not scored: every model cuts the same 24 in by 4 in trench. Chain speed is not shown because listings for the same machine quote 574 ft per minute and 1,800 ft per minute.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. The exception is warranty: a maker that doesn’t publish one gets no warranty counted, so that factor scores zero, the same as the shortest warranty on the scale, and is marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.