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Quick Verdict
DeWalt DWE402 4-1/2-Inch Corded Angle Grinder
Cordless angle grinders have caught up to corded in power, but runtime and cost still favor corded for heavy use. Here is a detailed comparison to help you decide.
Best For: Best Corded: Sustained Heavy Grinding
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Short Answer: Buy corded if you grind metal for more than 30 minutes at a stretch, do production welding, or want the most power for the least money. Buy cordless if you use a grinder intermittently, work on jobsites without power, or value the convenience of no cord. In 2026, cordless grinders have enough power for most tasks — the remaining advantage of corded is unlimited runtime.
Five years ago, this comparison was simple: corded grinders were more powerful, and cordless grinders were a compromise for convenience. That gap has closed dramatically. Modern 18V/20V brushless cordless grinders match or exceed the RPM and power output of most corded models. But "enough power" and "the right tool for the job" are different questions. Here is an honest comparison.
## Head-to-Head Comparison
| Factor |
Corded |
Cordless |
Winner |
| Peak Power |
11-15 amps (continuous) |
Comparable peak, lower sustained |
Corded |
| Runtime |
Unlimited |
10-30 min (grinding) |
Corded |
| Portability |
Needs outlet + cord |
Go anywhere |
Cordless |
| Weight |
4-6 lbs |
4-7 lbs (with battery) |
Corded |
| Safety Features |
Basic |
E-brake, anti-kickback, drop detect |
Cordless |
| Cost (tool only) |
$40-120 |
$100-200 (bare tool) |
Corded |
| RPM (4.5" models) |
10,000-11,000 |
8,500-9,000 |
Corded |
| No-cord hazard |
Trip/cut risk |
No cord |
Cordless |
## Power: Corded Still Wins (Barely)
A typical corded 4.5-inch angle grinder draws 11 amps continuously — that is about 1,300 watts of sustained power. A cordless 18V grinder on a 6.0 Ah battery can match that wattage in short bursts, but the battery chemistry limits sustained output. Under continuous heavy grinding, the cordless tool manages about 80-90% of the corded tool's cutting speed.
For most tasks — grinding welds, cutting rebar, removing rust, shaping metal — you will not notice the difference. The gap becomes apparent during extended heavy grinding on thick steel plate or continuous cutting of material with a cut-off wheel. If you are grinding for 30+ minutes straight, the corded tool maintains a consistent cutting speed that the cordless tool gradually loses as the battery discharges.
The exception is 36V cordless grinders (like the DeWalt FLEXVOLT or Metabo HPT MultiVolt). These match or exceed corded power output in every measurable way. But they cost $200-300 for the bare tool and require expensive high-capacity batteries.
## Runtime: The Real Difference
This is where corded grinders have an undeniable advantage. Plug in a corded grinder and it runs until you unplug it. A cordless grinder on a 5.0 Ah battery gives you approximately:
- **Light grinding (paint removal, rust):** 20-30 minutes
- **Moderate grinding (weld cleanup):** 12-20 minutes
- **Heavy grinding (cutting, thick stock):** 8-15 minutes
You can carry extra batteries, but quality 5.0 Ah packs cost $80-150 each. Three batteries give you 45-60 minutes of heavy grinding with swap breaks. Compare that to a $60 corded grinder that runs all day.
For intermittent use — a few cuts here, some grinding there, with breaks in between — runtime is not an issue. Cordless handles that pattern well. For production work where the grinder runs continuously for hours, corded is the only practical option.
## Safety: Cordless Wins
Modern cordless grinders include safety features that most corded grinders lack:
**Electronic brake.** Stops the disc in under 2 seconds when you release the trigger. Corded grinders coast for 5-10 seconds. A spinning disc on a tool you just set down is a hazard.
**Anti-kickback clutch.** If the disc binds, the clutch disengages the motor to prevent the tool from wrenching out of your hands. Some corded grinders have mechanical slip clutches, but the electronic versions on cordless tools respond faster.
**Drop detection.** Some cordless models (Milwaukee, DeWalt) detect if the tool is dropped and shut off the motor instantly. This prevents a running disc from bouncing across the floor.
**No cord.** This might be the biggest safety advantage. A cord running across a work area while you operate a spinning disc is a genuine hazard — tripping, snagging, and accidental cutting of the cord are all real risks.
## Cost: A Closer Look
The upfront cost comparison is misleading if you only look at tool prices.
**Corded scenario:** $60-120 for a good corded grinder (DeWalt DWE402, Makita GA4530). Plug it in and grind. Total cost: $60-120.
**Cordless scenario (already own batteries):** $100-180 for a bare tool. If you are on the Milwaukee M18 or DeWalt 20V MAX platform and already have batteries, the total cost is just the bare tool.
**Cordless scenario (starting from scratch):** $180-300 for a kit with battery and charger. If you do not own any batteries, the entry cost is significantly higher — and you are locked into that battery platform for future tools.
The long-term cost of cordless also includes battery replacement. Lithium-ion batteries degrade over 3-5 years of regular use. A corded grinder from 2010 still runs the same as the day you bought it.
## Use Case Recommendations
### Buy Corded If You:
- Grind or cut metal for 30+ minutes continuously
- Do production welding and need to clean welds all day
- Want the most power for the lowest cost
- Work in a shop with outlets nearby
- Do not already own a cordless battery platform
### Buy Cordless If You:
- Work on jobsites, farms, or locations without power
- Use a grinder intermittently (a few minutes at a time)
- Already own batteries on a major platform (Milwaukee, DeWalt, Makita)
- Value modern safety features (e-brake, anti-kickback)
- Cut pipe or rebar at various locations
### Buy Both If You:
- Do metalwork seriously — a corded grinder for bench work and a cordless for field work
- This is the most common setup in professional fabrication shops
## Recommended Models
If you are going corded, the **DeWalt DWE402** is a reliable, powerful 11-amp grinder at a fair price:
If you are going cordless, the **Milwaukee 2880-20 M18 FUEL** has the best combination of power, safety features, and battery ecosystem:
## Bottom Line
In 2026, cordless angle grinders are good enough for most users. If you use a grinder intermittently and already own batteries, go cordless and enjoy the safety features and convenience. If you grind metal for extended periods or want the simplest, most affordable option, corded still makes more sense. And if you do serious metalwork, the right answer is one of each. For specific model recommendations, see our best cordless angle grinders 2026 roundup.
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## Frequently Asked Questions
Is a cordless angle grinder as powerful as a corded one?
Top-tier cordless angle grinders (like the Milwaukee M18 FUEL or DeWalt 60V MAX) now match or exceed the power of standard 7-8 amp corded grinders. However, heavy-duty corded grinders (12-15 amp) still deliver more sustained power for continuous cutting and grinding on thick metal. For most DIY and light professional work, cordless is powerful enough.
How long does an angle grinder battery last during continuous use?
A 5.0Ah battery typically lasts 20-40 minutes of continuous grinding, depending on the load. Cutting metal drains the battery faster than surface grinding. Heavy cutting through thick steel may only yield 15-20 minutes. Having two batteries and a fast charger eliminates downtime on most jobs.
Is a corded angle grinder safer than cordless?
Neither is inherently safer. Both require the same safety precautions: eye protection, gloves, a guard, and proper disc selection. The cord on a corded grinder can be a tripping hazard, while a cordless grinder's motor can stall under heavy load and kick back. The most important safety factor is the operator, not the power source.
When should I choose a corded angle grinder over cordless?
Choose corded when you need sustained power for extended metal fabrication, when you are working near an outlet and do not need mobility, or when your budget is limited (corded grinders cost less for equivalent power). Corded is also better for stationary shop use where you are at a workbench all day.
Can I use the same discs on both corded and cordless angle grinders?
Yes, as long as the disc diameter matches your grinder (4-1/2 inch is the most common). The arbor hole size is standard at 7/8 inch for most grinders. Always check that the disc's maximum RPM rating meets or exceeds your grinder's no-load RPM. This applies equally to corded and cordless models.
