Impact drivers and impact wrenches look almost identical on the shelf, yet reaching for the wrong one can strip a screw or snap a bolt in seconds. Both hammer out high torque, but they aim that force at two very different fasteners.
Mechanics keep an impact wrench close for brute loosening power, while carpenters and DIYers grab an impact driver to sink screws fast without stripping heads. Swap them and you end up fighting cam-out or overtightened bolts.
Here is how the two tools actually differ in power, torque units, drive type, and the jobs each one owns, so you know which belongs in your kit.
Key Takeaways
- Impact Driver: Drives long screws, light bolts, and hex-shank drilling with a 1/4-inch hex collet; its torque is rated in inch-pounds and tops out around 2,000 to 2,600 in-lbs.
- Impact Wrench: Loosens rusted lug nuts and seized bolts with a square drive; its torque is rated in foot-pounds, ranging from about 100 to well over 1,000 ft-lbs.
- Interchangeability: Hex-to-square adapters let you cross over, but a wrench can shatter a driver bit and a driver lacks a wrench’s breakaway power, so it is a workaround, not a true swap.
- Budget Pick: The Campbell Hausfeld TL140200AV air impact wrench delivers 550 ft-lbs of torque in a 5-pound composite body, enough for lug nuts and most home garage bolts.
Quick Comparison Chart
| Key Features | Impact Driver | Impact Wrench |
| Cost | $$ | $$$ |
| Average Weight | 3.5 pounds | 6+ pounds |
| Power Source | Electric, battery | Compressed air (pneumatic), electric |
| Chuck Type | 0.25-inch hexagonal collet | 0.50-inch square drive (common) |
| Average RPM | Up to 3,600 | Under 2,000 |
| Average Torque | Up to about 2,000 in-lbs (roughly 167 ft-lbs) | 100 to 1,000+ ft-lbs |
| Best For | Drilling and driving screws | Loosening lugs and heavy bolts |
| Likely Users | Homeowners, DIYers, carpenters | Mechanics, steel workers, industrial pros |
One number trips people up when they compare the two: impact drivers are rated in inch-pounds (in-lbs), while impact wrenches are rated in foot-pounds (ft-lbs). To line them up on the same scale, divide inch-pounds by 12. A 2,000 in-lbs driver works out to about 167 ft-lbs, which is exactly why even a strong driver falls short of a mid-torque wrench on stuck bolts.
What Is an Impact Driver?
An impact driver is a compact cordless tool built to drive screws. It provides significantly more torque than a standard drill but keeps a compact profile. While it was once a specialist tool for pros, it is now a staple in almost every DIYer’s bag.
The defining feature of an impact driver is its 0.25-inch hexagonal collet. You pull the sleeve back to slip in hex-shank drill bits or driver bits. When the motor meets resistance, an internal anvil mechanism kicks in. This creates rapid rotational tapping (impacts) that drives the screw forward without stripping the head, since the hammering action keeps the bit seated and reduces cam-out.
One catch comes with the bits. The repeated sudden blows chew through standard screwdriver bits, which tend to snap or strip fast, so you need impact-rated hex-shank bits built for that shock load. Modern impact drivers usually feature brushless motors, variable speed triggers, and electronic clutches. They are loud, but they drive screws faster and easier than any other handheld tool.
When to Use an Impact Driver
Use an impact driver when you need to drive long screws into wood or metal. They excel at building decks, framing, or installing cabinetry. Because the concussion action helps keep the bit seated in the screw head, you are less likely to strip screws (cam-out) compared to a regular drill.
You can also use them for drilling holes, specifically with spade bits or hex-shank twist bits. While they aren’t as smooth as a standard drill for delicate holes, they power through thick studs with ease. You can adapt them to remove light bolts, but they lack the raw bust-out power that automotive work demands.
Usage Tip
Pros
- High torque for driving screws
- Compact and lightweight
- Reduces cam-out (stripping screws)
- Less recoil on the user’s wrist
- Versatile for drilling and fastening
Cons
- Requires impact-rated hex-shank bits
- Loud operation
- No built-in torque control (on older models)
- Can snap small screws
What Is an Impact Wrench?
An impact wrench is a high-torque tool that loosens and tightens nuts and bolts, most often lug nuts and seized fasteners. Often called an impact gun, air gun, or rattle gun, these tools deliver massive amounts of torque. You typically see them in auto shops connected to air compressors, though cordless electric versions have caught up fast. High-torque 20V and 24V models now produce over 1,000 ft-lbs of fastening torque, with even higher breakaway numbers for cracking bolts loose.
Unlike the hex drive on a driver, an impact wrench uses a square drive (usually 0.50-inch or 0.38-inch). This connects to impact-rated sockets.
These tools are not for delicate work. They are designed to loosen rusted, frozen, or overtightened nuts and bolts. If you are restoring an old car or working on heavy structural steel, you need an impact wrench. The downside is the weight and bulk; they are heavy, loud, and can be tiring to hold for long stretches.
When to Use an Impact Wrench
Reach for an impact wrench for automotive tasks like changing tires, removing suspension components, or breaking loose rusted engine bolts. They are also useful for driving large lag bolts into lumber during deck construction.
Torque needs help you size the tool. Most passenger-vehicle tire changes call for around 200 ft-lbs, while a mid-torque wrench of at least 400 ft-lbs covers nearly all suspension and undercarriage work. In a non-professional setting, you will likely only need this for car repairs or heavy equipment maintenance.
These tools are also loud, producing roughly 89 to 110 decibels depending on the type and drive size, so hearing protection is not optional. For reference, OSHA requires a hearing conservation program once noise exposure averages 85 decibels over an 8-hour day.
Impulsive noise gets its own line in the rule too: under 29 CFR 1910.95(b), OSHA says exposure to impulsive or impact noise should not exceed a 140 dB peak sound pressure level (1). Vibration exposure matters just as much: a workplace study published in 2025 measured hand-arm vibration at the trigger hand of pneumatic and electric impact wrenches at 5 to 24 meters per second squared, varying widely by tool and trade, and judged that exposure against a daily exposure action value of 2.5 meters per second squared and an exposure limit value of 5 meters per second squared, both averaged over an 8-hour shift (2).
Common Impact Wrench Mistakes
These tools are powerful enough to destroy your project if you aren’t careful. Avoid these errors:
Overtightening Fasteners
Impact wrenches are great at loosening bolts, but they can easily overtighten them during installation. This stretches the bolt, strips the threads, or snaps the head off entirely. Start bolts by hand, and use a torque wrench for the final tightening.
Cross-Threading
Never use the impact wrench to start a nut or bolt. If the threads aren’t aligned, the tool’s power will force the nut on anyway, destroying the threads permanently. Always hand-thread fasteners before pulling the trigger.
Using the Wrong Sockets
This is a critical safety issue. Never use standard chrome sockets on an impact wrench. Chrome sockets are brittle and can shatter or explode under the high-impact force, sending sharp metal shrapnel flying. Only use black, hardened impact-rated sockets.
Buying Too Much Power
Bigger isn’t always better. An ultra-high-torque pneumatic wrench might be overkill for a home garage. It can be heavy, hard to maneuver, and likely to snap smaller bolts. A compact cordless impact wrench or a “stubby” air wrench often gives you a better balance of power and control for DIY mechanics.
Pros
- Extreme torque output
- Removes frozen and rusted bolts
- Essential for automotive work
- Available in air and electric models
Cons
- Heavy and bulky
- Requires impact-rated sockets
- Can easily snap bolts
- Expensive
Impact Driver vs. Impact Wrench Summary
Think of it this way: impact drivers are for screws; impact wrenches are for nuts and bolts.
Impact drivers are versatile DIY tools. They drive deck screws, hang drywall, and drill holes. If you can only buy one tool for general home repair, get the impact driver.
Impact wrenches are specialized for high-torque removal. They don’t drill holes or drive wood screws well. However, if you work on cars, mowers, or tractors, they are the tool that saves your knuckles when bolts are stuck.
