The Verdict: A gas trimmer rated at 95 dB(A) uses up NIOSH's full daily noise allowance in about 48 minutes. A battery trimmer measured at 85.4 dBA stays near that limit for a full working day. Battery also costs about $1.33 less per hour to run. Gas keeps two real advantages: a tank refill takes minutes instead of a 55-minute recharge, and there is no battery to replace.
This comparison is compiled from manufacturer specifications, owner's manuals and published independent tests, each linked below. We did not test these trimmers.
The Four Trimmers Compared
EGO Power+ ST1623T
$299* on Amazon, with 4.0Ah battery and charger
- 56V, 4.0Ah battery (224Wh)
- 16" continuous cutting swath
- Telescopic carbon fiber shaft
- POWERLOAD line winding, LINE IQ auto-feed
Milwaukee M18 FUEL 2825-21ST
Price not quoted (not shown on Milwaukee's page)
- M18 REDLITHIUM HIGH OUTPUT XC8.0 battery
- 14" to 16" cutting swath
- QUIK-LOK attachment capability
- 0 to 4,900 / 0 to 6,200 RPM speed ranges
STIHL FS 91 R
$379.99* MSRP (STIHL USA)
- 28.4 cc 4-MIX engine, 1:50 fuel mix
- 16.5" cutting circle
- 24 fl oz fuel tank
- 12 lb without cutting tool and guard
ECHO SRM-2620T
$449.99* MSRP (ECHO USA)
- 25.4 cc engine
- 17" cutting swath
- 20.6 fl oz fuel tank
- 12.8 lb dry, including cutting head
How Much Trimming Do You Get Before a Refill?
Runtime is where sources are thinnest. Only two of the four have a published runtime figure.
| Trimmer | Published runtime | Source | Refill |
|---|---|---|---|
| EGO ST1623T (4.0Ah) | Up to 60 min rated; 50 min measured (high, no load) | EGO; TechGearLab | 55 min recharge on included 320W charger (EGO) |
| STIHL FS 91 R | Just over an hour per 24 oz tank | Pro Tool Reviews | Refuel from a mixed-fuel can |
| ECHO SRM-2620T | Not published (20.6 oz tank) | ECHO | Refuel from a mixed-fuel can |
| Milwaukee M18 FUEL (XC8.0) | Not published on product page | Milwaukee | Rapid charger included; time not published on product page |
On published numbers, one EGO charge and one STIHL tank are both roughly an hour of trimming. The practical difference is the refill. A gas trimmer is back to work as soon as you pour. The EGO battery needs 55 minutes on its included charger, so a job longer than one charge needs a second battery.
How Long Can You Run Each Trimmer Before Hitting the NIOSH Noise Limit?
NIOSH sets its recommended exposure limit at 85 dBA averaged over an 8-hour day. For every 3 dBA above that, it halves the allowed time. We ran the published noise figures through that rule:
| Trimmer and measurement | Level | Method and source | Daily time at NIOSH limit |
|---|---|---|---|
| EGO ST1623T | 85.4 dBA | Measured at ear height, TechGearLab | About 7 h 17 min |
| STIHL FS 91 R | 95 dB(A) | Sound pressure level, ISO 22868, STIHL manual | About 48 min |
| STIHL FS 91 R | 106 dB(A) | Measured at the ear, Pro Tool Reviews | About 3 min 45 s |
| ECHO SRM-2620T / Milwaukee M18 FUEL | Not published | Not listed on the product pages we checked | Not calculable |
The arithmetic: allowed hours = 8 / 2(level ā 85) / 3. At 95 dB(A), that is 8 / 10.1, or about 48 minutes. At 106 dB(A), it is 8 / 128, under four minutes.
What it means for you: with the gas trimmer, wear hearing protection from the first pull, even for a short edge job. Pro Tool Reviews' at-ear reading puts a normal suburban trim session far past the limit. The EGO figure sits just above 85 dBA, so it is quieter but not silent. The measurements come from different testers and methods, so compare them as orders of magnitude, not decimals. NIOSH's limit is a workplace recommendation, and it is the clearest published yardstick for a homeowner too.
Weight and Vibration
| Trimmer | Published weight | Vibration |
|---|---|---|
| EGO ST1623T | 12.8 lb with battery (TechGearLab, measured) | Not published |
| STIHL FS 91 R | 12 lb without cutting tool and guard (STIHL USA); 12.1 lb empty, almost 14 lb fueled (Pro Tool Reviews) | 5.3 m/sĀ² at each handle with mowing head (STIHL manual) |
| ECHO SRM-2620T | 12.8 lb dry, with cutting head (ECHO) | Not published on product page |
| Milwaukee M18 FUEL | Not listed on product page | Not published |
The weight gap is smaller than most people assume. A fueled STIHL and a battery-loaded EGO land within about a pound of each other on the figures above.
Maintenance: What the Gas Manual Asks For
Battery Trimmers
- Replace trimmer line as needed
- Clear debris from the head
- Charge per the maker's instructions
No fuel, carburetor or spark plug.
STIHL FS 91 R (per manual)
- Mix gasoline and 2-stroke oil at 1:50
- Do not store mixed fuel longer than 30 days
- Fit a new spark plug after about 100 operating hours
- Replace the air filter as scheduled
- Dealer valve-clearance check if power drops
Source: STIHL FS 91 R instruction manual
What Does an Hour of Trimming Cost to Run?
Every input below has a source. The two assumptions are labeled. Replace them with your own numbers.
EGO ST1623T (Battery)
- Purchase: $299* (Amazon, Sept 13, 2026)
- Battery energy: 224Wh (EGO)
- Electricity: 18.34Ā¢/kWh, US residential average, June 2026 (EIA)
- Per full charge: 0.224 kWh x $0.1834 = $0.04
- Charger losses: not published by EGO, not included
About $0.04 per charge
Assumption: one charge is about one hour of trimming (EGO rates up to 60 min)
STIHL FS 91 R (Gas)
- Purchase: $379.99* MSRP (STIHL USA)
- Tank: 24 fl oz = 0.1875 gal (STIHL)
- Gasoline: $4.157/gal, US regular, Sept 7, 2026 (EIA): 0.1875 x $4.157 = $0.78
- Oil: HP Ultra 2.6 oz, 48-bottle case $151.99* = $3.17 per bottle, one bottle per gallon at 50:1: 0.1875 x $3.17 = $0.59
About $1.37 per tank
Pro Tool Reviews: a tank lasts just over an hour
The operating gap is about $1.33 per hour in battery's favor. The EGO also starts $80.99 cheaper at these prices ($379.99* minus $299*). With no battery replacement, battery is cheaper on day one and stays cheaper.
When a Replacement Battery Changes the Answer
EGO's 4.0Ah battery carries a 3-year limited warranty. EGO does not publish an expected battery lifespan, so we do not assume one. If you do buy a replacement, Amazon listed the BA2242T 4.0Ah battery at $279* on September 13, 2026.
That purchase wipes out the $80.99 head start and leaves the battery setup $198.01 behind. At $1.33 per hour, it takes about 149 hours of trimming to earn that back. Assumption: if you trim 30 hours a season, that is about five seasons. Before then, STIHL's manual has the gas owner fitting a new spark plug at about 100 hours. Its price is not included here.
What to do: count your real trimming hours for one season. If you trim under 30 hours a year, a replacement battery bought within five seasons costs more than the fuel it saves. Buy the battery trimmer for noise and convenience, and do not count on it paying back a spare pack quickly.
When Gas Still Wins
Choose Gas If:
- You trim longer than one charge at a time and do not want to buy spare batteries. A tank refill takes minutes; the EGO battery takes 55 on its included charger.
- You would rather not face a battery purchase. A replacement EGO 4.0Ah battery was listed at $279*.
- You already keep mixed fuel for other 2-stroke tools, and use it within STIHL's 30-day storage window.
When Battery Wins
Choose Battery If:
- Noise matters. Published figures put the EGO near NIOSH's 85 dBA limit, while the STIHL measured 95 to 106 dB(A).
- You want the lowest running cost. About $0.04 per charge versus about $1.37 per tank on September 2026 prices.
- You trim only occasionally. There is no mixed fuel to go stale after 30 days.
- You want attachments on a battery platform. Milwaukee's 2825-21ST has QUIK-LOK attachment capability.
Our Picks, Based on the Sources
Battery Pick:
EGO Power+ ST1623T ($299*). It has the most complete published data of the four: EGO's 60-minute rating, TechGearLab's 50-minute and 85.4 dBA measurements, and a 55-minute recharge. EGO lists a 5-year tool and 3-year battery warranty.
Check Price on AmazonIf You Own M18 Tools:
Milwaukee M18 FUEL 2825-21ST. It ships with an XC8.0 battery and accepts QUIK-LOK attachments. Milwaukee does not publish runtime or weight on the product page, so check those before buying.
Gas Pick:
STIHL FS 91 R ($379.99* MSRP). It costs less than the ECHO and has published noise, vibration and tank-runtime figures. Budget for hearing protection and fresh fuel.
Sources
- EGO ST1623T product page: 60-minute rating, 16" swath, warranty
- EGO BA2242T 4.0Ah battery page: 224Wh, 55-minute charge on CH3200, 3-year warranty
- TechGearLab, EGO ST1623T review (Hale Milano, July 24, 2023): 50-minute runtime, 85.4 dBA, 12.8 lb
- Milwaukee 2825-21ST product page: battery, swath, RPM, QUIK-LOK
- STIHL USA FS 91 R page: MSRP, displacement, tank, weight
- STIHL FS 91 / 91 R instruction manual: 95 dB(A), 5.3 m/sĀ², 1:50 mix, 30-day fuel storage, 100-hour spark plug
- Pro Tool Reviews, STIHL FS 91 R review (Kenny Koehler, July 30, 2018): 106 dB(A) at ear, runtime per tank, weight
- ECHO SRM-2620T product page: MSRP, displacement, dry weight, tank, warranty
- STIHL HP Ultra 2-cycle oil: 48-bottle case price
- CDC/NIOSH noise exposure limit: 85 dBA over 8 hours, 3 dB exchange rate
- EIA gasoline and diesel prices and EIA residential electricity prices
Frequently Asked Questions
How long does the EGO ST1623T run per charge?
EGO rates it at up to 60 minutes of continuous cutting on the included 4.0Ah battery. TechGearLab measured 50 minutes on the high setting with no load. EGO says that battery recharges in 55 minutes on the included 320W charger.
How long does a tank last on the STIHL FS 91 R?
Pro Tool Reviews reported that the 24 fl oz tank lasts just over an hour before refueling. STIHL does not publish a runtime figure on its product page.
How loud are gas trimmers compared with battery trimmers?
STIHL's manual lists a sound pressure level of 95 dB(A) for the FS 91 R under ISO 22868. Pro Tool Reviews measured it at 106 dB(A) at the ear. TechGearLab measured the EGO ST1623T at 85.4 dBA at ear height. These come from different test methods, so treat the gap as approximate. Under NIOSH's 85 dBA limit and 3 dB exchange rate, 95 dB(A) allows about 48 minutes a day and 106 dB(A) under 4 minutes.
Is a battery trimmer cheaper to run than a gas trimmer?
Per hour, yes. Using EIA's September 7, 2026 gasoline price and STIHL's HP Ultra oil case price, one 24 oz tank of 50:1 mix costs about $1.37*. A full charge of EGO's 224Wh battery costs about $0.04 at EIA's June 2026 average residential rate, before charger losses. The gap narrows if you replace the battery: a replacement EGO 4.0Ah battery listed at $279* takes about 149 hours of trimming to earn back against gas.
What maintenance does a gas trimmer need that a battery trimmer does not?
STIHL's FS 91 R manual calls for a 1:50 gasoline and oil mix, says not to store mixed fuel longer than 30 days, and schedules a new spark plug after about 100 operating hours. It also lists air filter replacement and dealer checks such as valve clearance. Battery trimmers have no fuel, carburetor, or spark plug.
*Prices marked with an asterisk reflect the listed price at the time of review and may differ on the vendor's site.