Every string trimmer gets a score from 0 to 100% built from five 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. Trimmers are grouped by power source, battery and gas, and some factors have their own scales for each group.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per inch of cutting swath | 30% |
| Line | largest line diameter | 20% |
| Swath | cutting swath | 15% |
| Weight | the trimmer's weight as the maker states it | 15% |
| Warranty | warranty length | 20% |
Where the numbers come from
Cutting swath, line size, engine or battery, weight, warranty and the rest come from the maker’s product page, spec sheet or manual, or the maker’s own copy on its Amazon listing. Prices are checked at Amazon and the maker’s own store, and the lowest is used. Battery trimmers are priced as kits with batteries and charger.
The factors
Value is the current price divided by the cutting swath in inches, on a log scale for each group, so going from $20 to $10 per inch counts as much as going from $40 to $20.
| Group | Scores 0 | Full marks |
|---|---|---|
| Battery | $24 per inch | $8 per inch |
| Gas | $28 per inch | $10 per inch |
Line is the largest line diameter the head takes, since a trimmer needs more power to swing heavier line. For battery trimmers 0.065 in scores zero and 0.095 in full marks; for gas trimmers 0.080 in scores zero and 0.105 in full marks.
Swath is the cutting width: for battery trimmers 11 in scores zero and 16 in full marks; for gas trimmers 14 in scores zero and 18 in full marks.
Weight is the trimmer’s weight as the maker states it: for battery trimmers 13 lb scores zero and 7 lb full marks; for gas trimmers 15 lb scores zero and 9 lb full marks. Makers weigh trimmers differently, some without the battery or fuel, so the product page says what each figure includes.
Warranty is the length of the consumer warranty on the trimmer: 1 year scores zero and 5 years full marks. Battery warranties are listed separately.
What isn’t scored
Engine size, battery size, runtime, shaft type, line feed and attachments are listed but not scored. Runtime depends on the battery you buy and the weeds you cut. Independent tests are listed where they exist, but there are too few to score.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as 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.