Hammer Drill vs Impact Driver
Both tools hammer, but in different directions. That one detail decides which one your project needs.
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A hammer drill hammers forward along the bit to break up masonry while it drills. An impact driver hammers around the bit's axis to turn fasteners. Use a hammer drill for holes in brick, block and concrete. Use an impact driver to drive long screws, lags and Tapcons. An impact driver cannot drill concrete effectively, and a hammer drill is a poor tool for long structural screws.
On this page
Two kinds of hammering
The names cause the confusion. Both tools contain a hammering mechanism, but they hit in different directions:
- Hammer drill: pulses the bit forward, like tapping a chisel with a hammer while turning it. That pulverizes masonry at the cutting edge so the carbide tip can advance. Ratings are given in BPM (blows per minute), often in the tens of thousands.
- Impact driver: strikes around the axis, adding bursts of twisting force when a fastener resists. Ratings are given in IPM, typically 3,000 to 4,400 for current 18V models, plus a rated torque in inch-pounds.
Same word, opposite purpose. One helps a bit cut stone. The other helps a bit turn a screw.
Comparison table
| Feature | Hammer drill | Impact driver |
|---|---|---|
| Hammer direction | Forward (axial) | Rotational |
| Primary job | Drilling masonry; general drilling | Driving fasteners |
| Chuck | 3-jaw keyless, usually 1/2-inch | 1/4-inch hex collet |
| Modes | Drill, drive (clutch), hammer | Speed settings and special modes |
| Masonry drilling | Good for brick and block, fair in concrete | Poor |
| Long screws and lags | Fair; may stall and kick | Excellent |
| Precision drilling | Excellent (hammer off) | Fair |
| Size and weight | Longer, heavier | Compact, lighter |
When you need a hammer drill
- Anchoring a TV mount, shelf or railing into brick, block or concrete
- Drilling for Tapcons or sleeve anchors
- Running conduit or cable through a block wall
- Any general drilling in wood and metal, with the hammer turned off
For frequent concrete work, holes larger than about 1/2 inch in poured concrete, or chiseling, step up to a rotary hammer. See impact driver vs rotary hammer for how the piston mechanism differs.
When you need an impact driver
- Decks, fences, pergolas and framing with long screws
- Lag bolts and structural screws
- Self-drilling screws into steel studs
- Driving Tapcons after the hole is drilled
- Repetitive fastening where wrist fatigue matters
The Tapcon example: you want both
Concrete screws are the clearest case for owning both tools:
- Hammer drill: drill the hole with the carbide bit size the screw maker specifies, slightly deeper than the screw's embedment.
- Clear the dust from the hole. Dust left behind is the top reason concrete screws strip or snap.
- Impact driver: drive the screw on a low speed setting and stop the moment it seats. Overdriving strips the threads cut into the concrete.
Full steps in how to install Tapcon screws.
Can a hammer drill replace an impact driver?
For a handful of long screws, yes. With hammer mode off and the clutch at maximum, a hammer drill drives screws like any drill. For a deck's worth of 3-inch screws, or for lags, it is slower, it strips more screw heads, and it can twist hard in your hands when it binds. Read impact driver vs drill for why.
Can an impact driver replace a hammer drill?
No, not for masonry. The rotational blows do not chip concrete. Hex-shank "impact" masonry bits exist, but they are slow and wear quickly compared with a hammer drill. For holes in wood and thin metal, an impact driver with hex drill bits does a reasonable job.
What to buy
If you do not own a drill yet, a hammer drill plus impact driver combo kit covers almost every home and job-site need. Most brands offer brushless combos in exactly this pairing. If you already own a regular drill and rarely touch masonry, add an impact driver first and rent or borrow a hammer drill when a masonry job comes up.
Hammer drill + impact combos on Amazon Combo kit guide
Verdict
Choose by material, not by power. Masonry means a hammer drill. Long fasteners mean an impact driver. A hammer drill also covers everyday drilling, so if you are buying your first two tools, a hammer drill and impact driver pair is the most versatile choice.
Frequently asked questions
Can an impact driver drill into concrete?
Not effectively. Its blows are rotational, so they do not chip masonry. Even with a hex-shank masonry bit it will be slow, overheat the bit and wear the tool. Use a hammer drill, or a rotary hammer for frequent or large holes.
Can a hammer drill drive screws?
Yes. Switch off the hammer mode and use the clutch, and it works as a normal drill/driver. It will still struggle with long structural screws and lag bolts compared with an impact driver.
Is a hammer drill the same as a rotary hammer?
No. A hammer drill uses ratcheting discs to create many small forward blows, which is fine for occasional holes in brick and light concrete. A rotary hammer uses a piston to deliver far heavier blows with SDS bits, and it is much faster in poured concrete.
Which tool do I need to install Tapcons?
Both, ideally. Drill the hole with a hammer drill and a carbide masonry bit of the size the screw maker specifies, then drive the screw with an impact driver on a low setting.
Should I buy a hammer drill instead of a regular drill?
If you ever drill brick, block or concrete, yes. Most brushless 18V hammer drills cost only slightly more than the matching non-hammer drill and work as normal drills with hammer mode off. The trade-off is a little more length and weight.