That one design fact explains most of the confusion around voltage, runtime, and which trimmer fits your shed.
Worx 20V vs 40V: What The Voltage Numbers Actually Mean
Voltage sets the power ceiling, not the runtime. Run time is a separate equation: amp-hour capacity, cutting width, throttle setting, and vegetation density.
Two consequences follow. Amp hours matter as much as volts: a pair of 4.0Ah batteries carries roughly twice the energy of a pair of 2.0Ah packs, so a 40V trimmer with small cells won’t last in tall, wet grass.
The PowerShare platform makes this flexible: If you own Worx 20V gear, those batteries carry straight over to a 40V trimmer body.
Claimed Runtime By Model: Where The Minutes Come From
Worx’s published runtimes are manufacturer estimates from controlled conditions, not lab-standard tests; wet or woody growth will cut them. Treat “up to” figures as a ceiling, not a promise.
| Model | Runtime & Width | Best For |
|---|---|---|
| WG176.9 (20V brushless) | Up to 28 min; 13–15 in adjustable | Maintained yards up to ¼ acre |
| WG173 Nitro (20V brushless) | Up to 33 min; 13 in | Medium yards, light trimming |
| WG183 (40V) | Up to 28 min; 13 in | Medium yards, tougher grass |
| WG184 (40V trimmer/edger) | 13 in; 7,500 rpm; ~60 min charge | Trimming plus wheeled edging |
| WG185 (40V brushless) | Up to 50 min; 15 in | Large lots, heavy growth |
| Nitro 40V brushless | Up to 45 min; 15 in; dual 0.095 in line | Dense weeds, 25cc-equivalent power |
| 40V platform (2x 2.0Ah) | Covers average ½-acre homesite | Baseline 40V comparison point |
Note the pattern: the 20V WG173 claims more minutes than the 40V WG183, because a smaller cutting width and lower power draw stretch a charge. That’s the trade — wider heads and brushless 25cc-equivalent motors clear more ground per pass but drink more energy. Worx lists the WG184’s variable-speed throttle as its main power-management feature; lower speed on light grass buys back minutes.
Which One Fits Your Yard?
Pick 20V for routine trimming on a small, maintained lot, especially if you already own PowerShare batteries and want the lightest, least expensive body. Pick 40V when grass is dense, weeds are thick-stemmed, or the area is large enough that a 13-inch swath at low power would take all afternoon.
One buying trap: several Worx trimmers ship tool-only, with no batteries or charger — the WG184 tool-only listing states this outright. Before pricing a 40V trimmer against a 20V, confirm package contents; a bare tool plus two 4.0Ah batteries can cost more than the trimmer. Our breakdown of the best Worx weed eater battery options covers capacity and fit model by model. Worx’s WG184 40V trimmer and edger page lists the full spec sheet, including the paired-battery requirement and charge time.
Running A 40V Trimmer Correctly
Seat both 20V batteries fully and close the covers before starting. Fit the specified line and guard, then inspect the area for debris. Use low speed or ECO for light grass, step up for dense growth. Pull both batteries before clearing a jammed line, swapping the spool, cleaning, or storing.
Avoid these mistakes: running a 40V unit on one battery, comparing 20V and 40V runtimes without checking amp hours and cutting width, or assuming a US model matches a European one. Regional versions like the WG184E differ in included batteries, line specs, and voltage conventions — buy from the US listing and read its spec sheet.
Common Questions
Can I run a Worx 40V trimmer with just one 20V battery?
Does a 40V trimmer always last longer than a 20V one?
Not necessarily. Runtime depends on amp-hour capacity, cutting width, throttle setting, and grass conditions as much as voltage. The 20V WG173 claims up to 33 minutes while the 40V WG183 claims up to 28, because the smaller head draws less power. Compare batteries and widths, not volts alone.
Will my existing Worx 20V batteries work in a 40V tool?
Yes, as long as they’re PowerShare packs. Match capacity across the pair and confirm the model manual accepts your specific packs before relying on them.
Sources
- WORX. “40V Power Share 13-inch Cordless String Trimmer & Wheeled Edger, WG184 Tool Only” Documents the paired 20V battery requirement, 7,500 rpm speed, and charge time.
- WORX. “20V Brushless Adjustable 13–15-inch Cordless String Trimmer” Source for the WG176.9 amp-hour capacity, cutting width, and runtime claim.
- WORX. “Nitro 40V Brushless 15-inch Cordless String Trimmer Tool Only” Lists the 15-inch cutting diameter, dual 0.095-inch line, and 45-minute runtime.