Trimmers & Edgers
String trimmer buying guide: the four specs that matter
Swath width and runtime dominate the listings. Neither is in the top two things that will decide how you feel about the tool.
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.
Every string trimmer listing leads with swath width and runtime. Both are real specs and neither is in the top two things that determine whether you like the tool. Here is the list in the order it should actually influence you.
1. Line gauge
EGO and Ryobi both ship 0.095 inch. Greenworks ships 0.080 inch on the ST80L210. That is the single clearest specification difference in the trimmer roundup, and it is buried at the bottom of every retail listing.
2. How you get new line onto the spool
There are three approaches, and the difference is entirely about a job you will do a dozen times a season.
| System | How reloading works | Example |
|---|---|---|
| Automatic wind | Feed the line through and press a button; the tool winds the spool | EGO POWERLOAD |
| Bump feed | Tap the head to advance line while working; hand-wind the spool when empty | Ryobi RY402110, Greenworks ST80L210 |
| Pre-cut line heads | Drop in fixed lengths of line; no spool at all | Not on any of the trimmers we have specs for |
Bump feed is fine while there is line on the spool. The moment it empties you are sitting on the grass winding nylon that wants to spring off the reel. If you trim weekly, an automatic head is worth more to you than fifteen minutes of runtime.
3. Loaded weight, not bare weight
This is a tool held out in front of you on a shaft roughly six feet long. Weight at the far end has leverage, and the number in the listing is usually the bare one.
| Trimmer | Bare | With pack | Difference |
|---|---|---|---|
| Ryobi RY402110 | 8.8 lb | 12.9 lb (6.0Ah) | +4.1 lb |
| Greenworks ST80L210 | 7.1 lb | Not published | — |
| EGO ST1521S | Not published | Not published | — |
Ryobi is the only one of the three to publish both figures. EGO publishes neither.
Ryobi's honesty here is genuinely useful: 4.1 lb of battery is a third again on top of the bare tool. If you are sensitive to this, the fix is simple and nobody tells you it — fit a smaller pack. A trimmer draws roughly 3.6-4.7Wh per minute, so even a small pack gives a usable session.
4. Shaft material and construction
Carbon fiber is stiffer per unit weight than aluminum, which means less flex when the head loads up in thick grass. EGO backs its carbon fiber shaft with a lifetime warranty — the only lifetime term anywhere on this site — which says more about the material than any marketing sentence could.
Also check whether the shaft is split. A split shaft takes attachments, which turns one power head into a trimmer, an edger and a pole saw. That is a meaningful cost saving across a platform, and it is why we treat multi-head systems as a platform feature rather than a trimmer feature.
The specs everyone leads with
Swath width
15 to 17 inches across the tools here. Wider covers open verge faster and is harder to control around beds. Ryobi's adjustable 15-to-17 mechanism is the best answer to that trade, and honestly the difference between 15 and 16 fixed is not something most people would notice.
Runtime
Published figures run 30 to 67 minutes, and they mostly measure which pack the kit shipped with rather than anything about the tool. All three trimmers land within about 25% of each other on watt-hours per minute. Fit a mower pack and any of them runs for over an hour — the watt-hour guide explains the math.
Voltage
40V, 56V and 80V trimmers here, all doing the same job with the same efficiency. The 40V Ryobi and the 80V Greenworks both come out at 3.6Wh per minute. Voltage is a platform decision, not a trimmer decision.
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.
EGO Power+ 15" POWERLOAD Carbon Fiber ST1521S
EGO · EGO 56V ARC Lithium · Our score 8.9/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
A lifetime shaft warranty and a head that reloads line at the push of a button -- the two things that actually go wrong with a string trimmer.
Published specs
| Cutting swath | 15 in |
|---|---|
| Line | 0.095 in dual-feed spiral twist |
| Head | POWERLOAD automatic winding |
| Shaft | Carbon fiber, split shaft |
| Battery (kit) | 56V 2.5Ah |
| Runtime claim | Up to 30 min on 2.5Ah |
| Charge time | 50 min |
| Warranty | 5-yr tool / 3-yr battery, lifetime shaft |
Source: POWER+ 15" POWERLOAD String Trimmer with Carbon Fiber Shaft, egopowerplus.com
56V x 2.5Ah = 140Wh. 30 minutes of published runtime from 140Wh is about 4.7Wh per minute -- roughly a quarter of what a blower on turbo burns.
What the numbers favor
- Lifetime warranty on the carbon fiber shaft, published
- POWERLOAD winds the line for you -- the job everyone hates
- 0.095 in line, the heavier of the two common home gauges
- Split shaft, so it takes EGO's multi-head attachments
What they don't
- Ships with the small 2.5Ah pack; 30 minutes is a modest published runtime
- EGO does not publish a weight for this configuration
you only edge a short driveway. An 8 in edger attachment on a power head you already own does that job better and costs a fraction.
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.
Ryobi 40V HP Whisper 17" Carbon Fiber RY402110
Ryobi · Ryobi 40V · 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.
67 published minutes and a swath you can dial from 15 to 17 inches -- the only adjustable-swath trimmer here.
Published specs
| Cutting swath | Adjustable 15-17 in |
|---|---|
| Line | 0.095 in bump feed |
| Shaft | Carbon fiber |
| Battery (kit) | 40V 6.0Ah |
| Runtime claim | Up to 67 min |
| Weight | 8.8 lb bare / 12.9 lb with 6.0Ah |
| Length | 72.25 in |
Source: 40V HP Brushless 17" String Trimmer (RY402110), ryobitools.com
40V x 6.0Ah = 240Wh. 67 minutes from 240Wh is about 3.6Wh per minute -- the most efficient published figure of the three trimmers here.
What the numbers favor
- 67 minutes published, more than double the EGO kit's 30
- Swath adjusts 15-17 in, so tight borders and open verge get the same tool
- Best published watt-hours per minute of the trimmers on this page
- Whisper Series noise engineering, same line as the 57 dB blower
What they don't
- 12.9 lb with the 6.0Ah pack fitted -- the heaviest trimmer here, and it is held at arm's length
- Ryobi publishes no noise figure for this specific model
- Bump feed, not an automatic reload head
you have wrist or shoulder trouble. 12.9 lb on the end of a 72 in shaft is a lot of leverage, whatever the runtime says.
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.
Greenworks 80V 16" String Trimmer ST80L210
Greenworks · Greenworks 80V · Our score 8.4/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
7.1 lb bare with a 30-minute recharge and a 4-year battery warranty -- the lightest way onto the 80V platform.
Published specs
| Cutting swath | 16 in |
|---|---|
| Motor | Brushless, 6200 RPM |
| Line | 0.080 in spiral twist dual-line bump feed |
| Battery (kit) | 80V 2.0Ah |
| Runtime claim | Up to 45 min |
| Recharge | 30 min |
| Weight | 7.1 lb without battery |
| Warranty | 3-yr tool / 4-yr battery |
Source: 80V Cordless 16" Brushless String Trimmer (ST80L210), greenworkstools.com
80V x 2.0Ah = 160Wh. 45 minutes from 160Wh is about 3.6Wh per minute, matching the Ryobi almost exactly despite half the pack size.
What the numbers favor
- 7.1 lb bare, the lightest published trimmer weight here
- 30-minute recharge, the fastest on this page
- 4-year battery warranty
- Publishes motor RPM, which neither EGO nor Ryobi does for their trimmers
What they don't
- 0.080 in line is the lightest gauge here -- it will break more often in heavy weeds
- 160Wh included is a small pack for an 80V platform
- Bump feed, not automatic reload
you cut heavy brush or thick weed stems. 0.080 in line is a lawn-edge gauge, not a bramble gauge.
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.
Common questions
What is the best string trimmer for home use?
What size string trimmer line should I use?
What is the difference between bump feed and automatic feed?
Is a carbon fiber shaft worth it?
Should I get a straight or curved shaft trimmer?
How much should a string trimmer weigh?
Sources
Read next
- Trimmers & Edgers
The line gauge and the head design decide whether you enjoy this job or dread it.
- Best cordless string trimmers of 2026
Three trimmers ranked on swath, line gauge, weight and energy per minute.
- Best cordless lawn edger
The attachment usually beats the dedicated machine here. Published runtimes and the depth spec that matters.
- 40V vs 80V: what the voltage on the sticker actually buys you
Volts x amp-hours = watt-hours. The one calculation that makes every battery spec comparable.
- Battery Platforms
Pick the system once and the next four tools are decided for you. Start here.