Dewalt 20V Atomic Compact Impact Driver Review

Dewalt 20V Atomic Impact Driver – Model DCF850

Dewalt 20v Atomic Compact Impact Driver

Manufacturer: Dewalt
Model number: DCF850
Price: $199.00
Power source: 20V
Weight: 2.1lbs
Dewalt 20v Atomic Compact Impact Driver is a 3-Speed Impact Driver, with a length of less than 4 in., that can handle tight applications such as framing without the use of a second tool. This Impact Driver is small and lightweight, but its brushless motor provides enough power to drive large-diameter fasteners.

A Versatile Installing Tool 

The 20v Atomic line is intended to be compact and powerful for a variety of applications. We’ve used it for:

  • Decking board installation
  • Stair stringer installation
  • Installing Simpson structural screws and hardware
  • Installing cabinets

This Atomic line offers a more compact size and reduced tool weight, [2.1 lbs] making it ideal for overhead applications and tight workspaces.

Dewalt DCF850 comes in a kit that contains the tool, belt hook, 20v 5.0Ah battery, charger, and contractor bag. The other option is purchasing it as a bare tool if you are on the platform already and do not need the charger and battery.

DCF850 Specifications

  • Drive 1/4 in. (quick release hex shank)
  • Impacts/Min 3800 ipm
  • Max Torque (in-lbs) 1825 in-lbs
  • No Load Speed 3,250 rpm
  • Tool Height 8 in
  • Tool Length 3.97 in
  • Tool Weight 2.1 lbs

Does Size Matter for Impacts?

Does size matter to you when it comes to the selection of 1/4″ impacts? We definitely think it does. It all has to do with the applications you are using it for. We do a fair amount of deck builds, and during a recent deck stair replacement, we put the Dewalt 20v atomic compact impact driver through the paces we would any other impact driver. [photo below]

We were really impressed with the power of such a small compact tool. What made this impact shine was the ability to get into tight places where we normally would have to switch to a right angle drill or even a palm nailer when installing our Simpson Strong-Tie Metal connector screws diagonally through our joist hangers. A definate game-changer for us!



Comparing the DCF850 to the DCF887

The Dewalt DCF850 in comparison to the DCF887 is apples to apples with one exception, its size. Both models offer of 3,250RPMs, 3,800BPM as well as 1,825 In-Lbs of torque. The only difference is the overall size. Dewalt has managed to get the exact power of the full-size impact into the small frame of the compact without sacrificing any power. Impressive power with a BIG noticeable footprint reduction,.

Overall Impression

Dewalt’s DCF850 has the same specs and power as the XR DCF887, but is nearly half the length! You can’t go wrong with this cordless compact impact. When Dewalt’s new Power Stack batteries arrive in December, this impact driver will be unstoppable! We highly recommend it!

Dewalt 20v Atomic Compact Impact Driver

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About the author

Scott Arnold

Contributing Editor Scott Arnold is the owner of Scott Arnold Remodeling LLC out of Waltham MA. Custom decks, fireplace makeovers, kitchens and bathrooms, Scott enjoys the frame to finish concept. Scott will share his perspective on tools as carpenter and remodeler here and on

@scottarnold34Scott Arnold

All posts by Scott »


  1. Mr. Me

    My experience with the dcf850 is rather disappointing for the tasks in which I expected it to be able to handle. These tasks weren’t out of the ordinary and they were all done with my dcf887 prior to buying the dcf850 and the dcf887 was able to manage these tasks with ease. The first task was to drive some 5″ hedlock screws in a scheduled pattern to sandwich a triple lvl which we had just installed. From the get-go, I was immediately made aware that the dcf850 had nowhere near the power of the dcf887. It struggled more and more with each screw I tried to drive home. Not only that, but it was incapable of burying the head below the surface of the lvl which is going to be finished with drywall. After three screws, I grabbed my dcf887 and finished the job. I had to drive in 27 screws. It proved to be very incapable of such a task. About a week later, I was tasked with fastening deck boards after we built it. We typically use the camo hidden deck fastening system for wooden decks. So, I thought that being that the dcf850 has a much higher rpm than the dcf887, I thought it would be up to the task. Once again, it proved itself to be incapable of handling the work. After a handful of screws, I went to grab my dcf887 and as usual, it handled the work very efficiently. Given that the size of the dcf850 is significantly smaller than the dcf887, the hammer and anvil hit nowhere near as hard as the dcf887. This inefficiency is most definitely because the size of the striking mechanism has been reduced by more than half of the hammer and anvil of the dcf887. I know this because I took it apart in order to get a better understanding of what made it so weak. And it was clearly obvious:the size reduction of the parts.

    1. Scott Arnold

      Mr Me,
      Thanks for the insight and I am sorry to hear that you have had issues with your DCF850. All the tasks that we put it through we did not have an issue. We have used it for a multitude of things such as installing simpson strong ties 2-1/2″ connecting screws. Tons of 3-1/8″ GRKs. 5″ Headloks into out deck posts into blocking. How are the batteries you are using? Any issues with any other tools? If not perhaps something is wrong with the tool? Maybe reach out to Dewalt directly and see if they have any insight.
      TBB Crew Scott

      1. 536joe

        Maybe he forgot to set the impact in 3rd speed.

        1. Larry

          We have noticed the same with the dcf850
          I have tried a few different dcf850 on speed 3
          And does not even come remotely close to having
          The same power as the dcf887 both had fully charged
          Dewalt 5ah batteries

  2. This is useful information. I have spent hours sifting through the data on various impact tools, trying to figure out what to buy. From batteries changing to the new Powerstack technology to drivers that changed to compact versions and kits that mix and match in all kinds of configurations. Brushless with a light and powerful battery. Put aside a day.

    I’ve been at it for almost two solid days so far. Terminology like MAX, Powerstack, ATOMIC, XR, BPM don’t mean anything to me for example. Also, some prouct/Kit descriptions don’t match their pictures to the detailed text in the description doesn’t match the header. In those cases Amazon representatives tell me to trust the text and not the picture.

    Add to that four other manufacturers with a variety of combinations in kits and you understand why I have spent more than 10 hours doing my “research”, it’s exhausting and time wasting in a major way. It should not be this difficult to order a good impact driver. I am not a contractor but I would like to be able to unscrew the blades from my ride-on lawn tractor with one of these tools.

    When I think about the time I have spent (still not finished) trying to understand the various parameters associated with these tools I shudder. Batteries are now at least three different versions, the older traditional lithium types, the new yellow versions of the same, then the power stack batteries where you have to dig deep to find the Ah. Then try to sort out the size, weight etc. It’s pretty crazy.

    So far I’ve sent back two kits because they didn’t meet my needs. For example, I don’t really want to buy a kit that has 2x2Ah batteries. I would rather buy a kit with one 5Ah battery but I want it to be light as possible and have a long life. As far as I can see only the 1.7V PowerStack is available in a kit.

    There is a 5Ah battery available but not in the Powerstack series. It would be good to have a Powerstack 5Ah with a Powerstack 2Ah and a DCF845P1 ATOMIC , brushless, 3-speed with variable speed, 1825 in-lbs torque, 3500 IPM, 3400 RPM, 3 speed settings, variable speed, maybe a 20V MAX XR, I’m not sure. Prices fluctuate depending on configuration.

    IMHO I view the current method of shopping for an impact tool kit as extremely unfriendly and cumbersome. At this stage I’m not sure if I’m ever going to make it to the check out.

  3. Tom Szura

    Same Comments as previously given, not the torque I expected, too low to drive 3 inch screws to bring two 2 x 8 together. The clutch kicks in and the screw stays 1/2 in above flush. Needed to switch to the drill to finish the job.
    Expected the driver to provide the same torque as the drill

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