Hammer Drill vs. Impact Driver – What’s the Difference & Do I Need Both?

Goodness me, there’s just so much to keep up with in the world of power tools.

Head over to your local hardware store, and you’ll find literally dozens of different contraptions (change that to hundreds if you’re shopping online) just for drilling holes and screws. With so many different options, styles, designs, and manufacturers to choose from, it’s got to be an overwhelming experience for a beginning DIY’er to try and choose the right product.

Hopefully, this is where we can be of some assistance.

In this article, we’ll do a detailed head-to-head comparison between an impact driver and a hammer drill; what’s the difference between the two, and what are some appropriate uses for each.

Do you need both in your garage? Read on, and find out for yourself.

General Overview: Hammer drill vs. Impact Driver

Ok, very generally speaking, a hammer drill serves one main purpose: drilling holes through masonry (concrete/drywall).

Here’s a good little video really showcasing the advantages and functionality of both the hammer drill and the impact driver.


An impact driver’s main purpose is driving big, long screws into tough material (studs, concrete/masonry, drywall, etc.) They’re simply more powerful than your standard cordless drill/driver.

Thousands of people a day probably get by just using a standard drill for these purposes, but we’ve all run into the problems faced when trying to do so: broken/burnt out drill bits, jammed screws, and stripped screw heads.

Thus, both the hammer drill and impact driver really do serve legitimate purposes – if you do end up adding one or both to your power tool arsenal, you’ll wonder how you ever managed to get by with just your standard power drill.

Hammer drill and Impact driver: Key differences

One of the major differences between an impact driver and a hammer drill is the types of bits they’ll accept. Hammer drills are much more universal in this regard, as their 3-jaw chuck will accept both round and hex bits. Impact drivers, on the other hand, have a locking collet that only accepts hex-shanked bits.

You may have run into problems from time to time with your standard drill (probably when trying to push it beyond its limits) where the chuck has lost its grip on the drill/driver bit, or even had it fall out entirely. This doesn’t happen with an impact driver.

As far as differences in action, we’ll discuss those in the next section below.

Hammer drill action vs. Impact driver action

Without getting into some pretty intense physics/engineering type stuff (which is over our heads anyways), we’ll talk briefly about the differences in action between the hammer drill and the impact driver.

A standard electric drill simply spins the drill or driver around – there’s no additional action.

With the hammer drill, the spinning action is combined with, you guessed it, a hammering action. The force is applied exactly like that of a hammer; a bam-bam-bam-bam force is applied along the axis of the drill bit, pounding it in while simultaneously spinning.

Almost all hammer drills have a button or switch that you have to hit to turn on the ‘hammering’ action – maybe your cordless drill is actually a hammer drill, and you’ve never even realized it.

The action on an impact driver, on the other hand, is rotational – there’s no top-to-bottom force applied to the driver bit. The best way to describe the action of an impact driver is this: imagine you’ve got a wrench on a super-tight, locked-up nut that you’re trying to loosen up. You’ve about given yourself a hernia trying to break the nut free, but it won’t budge.

So you take a hammer or a heavy pipe or something of the sort, and start hitting the wrench with it – increasing the rotational force that’s being applied to the wrench. This is what’s happening with an impact driver; much greater rotational force is being applied to the screw head. This is why impact drivers can drive long screws through heavy-duty material without stripping the heads – they’re much more powerful than a standard drill.

Summary: Uses for each

To summarize, a hammer drill is used for drilling holes into masonry (i.e. concrete backer board and drywall). Unless you just enjoy blowing out and breaking bits using your standard drill, it’s definitely a practical, functional tool – certainly not a gimmick.

The impact driver is used for driving big screws into heavy duty material like studs and masonry. For example, hanging cleats for wall cabinets, driving into concrete backer board, or building a deck where you’ll be driving a lot of long 3 ½” screws, would all be jobs where an impact driver is all but mandatory. The additional torque on the screw head makes for faster, more powerful driving than even the best standard cordless drills out there.

Another thing to consider is that unlike standard (or hammer) drills, impact drivers don’t have a big, bulky internal clutch – they’re more compact tools that are nice to handle in tight spaces. Also, since the additional torque in an impact driver is rotational, the force isn’t transferred into your hand/wrist like it is with a hammer drill, which can be pretty fatiguing to use for hours on end.

Top Picks: Our Favorite Impact Drivers

DeWalt DCF887B 20-volt MAX ¼”

This is one of the most top-notch impact drivers on the market, with DeWalt’s renowned 20-volt MAX battery providing ample power for hours on end. Probably our first-choice pick for a quality impact driver at a decent value.

Makita DT03Z 12-volt cordless impact driver

A more economically-priced, albeit much less powerful driver with its 12-volt battery than the DeWalt. This is good tool if you don’t want to splash the cash on a top-notch product, but still would like to keep an impact driver in the garage, just in case.

Milwaukee 2656-20 M18 Li-Ion 18-volt impact driver

Another great tool – a bit of an intermediate between the DeWalt and the Makita. In our experience, Milwaukee’s M18 series can pretty much hang tit for tat with the 20-volt DeWalt MAX batteries, but they don’t seem to be able to hold out for as long a period of time.

Top Picks: Our Favorite Hammer Drills

DeWalt DCD996B 20-volt MAX 3-speed hammer drill

One of the best hammer drills on the market, as you’d expect from DeWalt’s 20-volt MAX series. A 3-mode LED work light is included for those ‘dark’ jobs – comes in handy a lot more often than you’d think.

Bosch HDS181A-01 18-volt ½” compact impact driver

This one is a bit more pricey than the DeWalt, as it comes with the 18-volt battery and charger. We think the DeWalt is just a bit more powerful (makes sense with 2-volts more power), but this is still a fine tool that’ll get you through all the backer board and drywall you need.

Lastly, here’s a couple convenient combo packages that include both a hammer drill and the impact driver, if you’re looking to add both tools to your arsenal at once:

Bosch CLPK222-181 18-volt 2-tool kit; ½” hammer drill and ¼” hex impact driver

DEWALT 20V MAX XR Brushless Impact Driver and Hammer Drill Combo Kit, Premium 4.0Ah (DCK299M2)

Hitachi KC18DBFL 18-volt Li-Ion hammer drill/impact driver combo

Bottom Line

Tired of getting jammed-up with your standard cordless drill, burning out bits and stripping screws? Then go ahead and treat yourself to an impact driver and/or a quality hammer drill. Like we said, you’ll wonder how you ever managed to get by with just that standard drill.

About Jake Roberts

I have been working on wood projects since I was a young boy. My dad made rocking chairs and other furniture to sell all over the mid west. I alway enjoy the next challenge to build to keep sharpening my working skills.

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