DIY Filing Cabinet Desk {Easy Modular Desk Design}

**This DIY filing cabinet desk is sponsored by The Home Depot as part of the #THDProSpective program. This post also contains affiliate links. See policies.

DIY Modular filing cabinet desk with file cabinet on left and shelving unit on right

I’m having a really hard time describing this project as one specific thing because it’s actually a MODULAR DIY Filing Cabinet Desk. And since it’s “modular,” it could be made into so many different things.

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Since I’ve been building several desks lately, I thought I’d stick with that theme and share this idea as kind of a modular DIY filing cabinet desk. PS Have you see all the recent desks?? Check them out here.

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But, I actually built this for my dad’s office space in three separate pieces–two filing cabinets and a shelf cabinet–so he can put them together as an office storage console…see how naming this project was so difficult? It doesn’t HAVE to be a desk.

This project is basically just building identical sized cabinet boxes, deciding how many you want and what you want to put inside.

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So, in this post, I’m sharing how to 1. build the simple cabinet boxes, and 2. how to turn them into either shelves or filing cabinets so you can mix and match as needed 🙂

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{By the way…you’ve seen those DIY filing cabinet desks, right? Where they just place a top on two metal file cabinets and call it a desk. This is basically that project…only I’m showing you how to actually BUILD the filing cabinets instead of using those old metal ones!}

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I’ve got the plans, details and dimensions below and I’ll show you how they came together here in this video.

For this Modular DIY Filing Cabinet Desk, You Will Need:

You may like: The Must Have Tools For Cabinet Building

Now, let’s get building 😊

Step 1: Build Modular Cabinet Boxes

This project is basically made of three identical plywood cabinet boxes.  One has shelves and the other two have drawers.  So the first thing I did was build these three cabinet boxes identical in size.

Unfinished modular file cabinet desk assembled

I used my Rip Cut and circular saw to first rip my 3/4″ plywood sheet down into strips 20″ wide. You can cut two (29 1/4″) sides and a (22 1/2″) bottom from one strip, so you need one 20″ strip for each cabinet box you’re building.

RELATED: If you’re interested in learning more about how I cut down my plywood sheets, I’ve got a detailed tutorial here.

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Then, I ripped a 3″ strip from the remaining plywood sheet to give me a piece for the toe kick at the bottom and the two support strips at the top. I trimmed these down to 22 1/2″ long on the miter saw, but you could also trim them on the circular saw if you’d rather.

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I edge banded all the exposed plywood edges that will face the front once assembled, then I used a pocket hole jig to drill 3/4″ pocket holes into the edges of the bottom panel and the ends of the top supports and toe kick.

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Then, I assembled the cabinets with wood glue and 1 1/4″ pocket hole screws.

Bottom panel of modular desk cabinet assembly diagram
Toe kick attached to modular file cabinet desk cabinet diagram
Top supports attached on modular cabinet diagram

Lastly, I nailed (you could also just screw or staple) a 1/4″ plywood back onto the cabinet. You’ll notice, these modular cabinets are 24″ wide overall. So if you want to fill a 6ft. space, you can just put three side by side, or 8ft, you can use four, etc.

Back panel attached to modular cabinet diagram

I repeated this process twice to give me three total cabinet carcasses. Build as many as you want, then decide how you want to fill them–shelves or drawers 🙂 For shelves, see step 2 and for drawers, skip to step 3.

A Note About the Drill & Driver 

For this DIY filing cabinet desk project I tried out the new Ryobi ONE+ HP 18V Brushless Compact Series Drill and Driver to see how they performed.  These are not the older Ryobi drill and driver you may be used to seeing.  Old in the back, new in the front below.

Old vs New Ryobi ONE+ HP drill driver sets side by side on workbench

The new Ryobi ONE+ HP (HP = high performance) line is brushless, compact, and packs a NOTICEABLE upgrade in performance in a 30% smaller and 23% lighter weight package. (Seriously…check out the YouTube video above for a close up side by side comparison.)

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My super quick 100% honest personal opinion: When I say these aren’t the old Ryobi tools, I mean it. The Ryobi ONE+ HP drill & driver set is a VAST (do you see those all caps??) improvement over the older, heavier, and bulkier ONE+ set.

Ryobi ONE+ HP drill drilling holes for file cabinet drawer hardware

I honestly enjoyed using them on this project and you’ll definitely be seeing more of these in my future projects…keep an eye out in future projects so I can prove it to you 😉 These are legit.

Using Ryobi ONE+ HP driver to assemble modular cabinet for filing cabinet desk

You can check out all the details on the Ryobi ONE+ HP 18V Compact Drill and Driver Kit (comes with drill, driver, 2 batteries and a charger!) on the Home Depot website here.

Step 2: Add Shelf to Modular Desk Cabinet

Now back to the build 🙂 If you want to make one (or more) of your cabinets from step 1 into a shelf, it’s pretty simple.

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For the shelf cabinet, I used a shelf pin jig to drill holes along both sides to give me the option of an adjustable shelf. 

Using Ryobi ONE+ HP drill to drill shelf pin holes in modular desk cabinet

Then, I just used shelf pins to install a 3/4″ plywood shelf. You can place this as low or high as you want. But I simply cut my shelf 18″ deep x 22 1/4″ wide.

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Helpful tip: when cutting adjustable shelves like this, cut them about 1/4″ shorter in length than the width of the inside of the cabinet to give you some wiggle room when sliding them in and out.

Modular desk cabinet with shelf installed diagram

At this point, the shelf cabinet is pretty much complete, so I set it to the side and began work on the drawers. If you don’t want drawers, skip to step 5.

Step 3: Build File Cabinet Drawers

I installed two pair of ball bearing drawer slides into two of the cabinets with wood screws.  I’ve got a super detailed drawer building guide here if you’d like more info on exactly how I build drawers and install slides.

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I installed the bottom slides all the way at the bottom of the cabinet and the top slides, 12 1/2″ up from the bottom. This gives plenty of room above each drawer for the file folder tabs.

Modular cabinet with drawer slides installed

I ripped down some 3/4″ plywood strips to use for the drawer boxes to 10 1/2″ wide, trimmed them down to size (shown below), and cut a dado 1/2″ from the bottom to install the ¼” plywood drawer bottom. You can get more details in my drawer building guide here.

Exploded drawer box diagram

Once all the drawer pieces were cut down, I drilled pocket holes into the ends of the front and back pieces for assembly like shown above.

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But, before attaching anything, I needed to cut dadoes to insert the file folder rails.  If you just want regular drawers, you can ignore this part.

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I basically used ¼” plywood as the rails for the file folders like seen below.  I glued and screwed scrap 1/4″ plywood onto one side of the drawer box, then cut a dado to slide the other piece in place for the other side of the file folder. 

front to back filing cabinet drawer pulled out of DIY filing cabinet desk

That way, if they decide they don’t need file drawers, they can remove the plywood in the dado and use the whole drawer for regular storage.

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To do this, I measured out the file folder and marked where to cut to slide the plywood in place. In my particular case, I needed exactly 12″ gap between my two plywood rails. So here’s the dimensions for my dado (I cut out between 12 1/4″ to 12 1/2″ from the edge to make a 1/4″ dado).

Front to back filing cabinet drawer dado cut diagram

Do note that different style folders may require different measurements so double check yours before cutting.

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To cut the dadoes, I used my AccuCut and circular saw (if you don’t have an AccuCut, you can just use a straight edge clamped to the piece to guide the saw) to make a cut ¼” deep on my marks.  I moved the track over slightly and cut again until I had a dado wide enough to accept the ¼” plywood. (I used a similar method in my DIY Pie Box Carrier project.)

Using AccuCut and Circular saw to cut dado for filing cabinet rails

Once one side was cut, I cut the opposite side of the drawer box, then, I assembled the box with 3/4″ pocket holes and 1 1/4″ pocket hole screws, installing the ¼” plywood bottom into the dadoes cut earlier.

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As a side note, I cut two drawers so the files will go side to side and two so they’ll go front to back.  I wasn’t sure which my parents wanted, so I mixed and matched.  Either way works fine…you can cut them whichever direction you prefer.

Close up of side to side filing cabinet drawer railing system using 1/4" plywood

Here’s the dimensions for turning them the opposite way.

Side to side filing cabinet drawer dado cut dimension diagram

I cut the scrap piece of ¼” plywood to glue and screw into the side of the drawer box, leaving about ¼” sticking up for the folder to hang on. Then, I cut another piece of 1/4″ plywood to slide into the dadoes, leaving ¼” sticking up from the top edge of the drawer.

Using Ryobi ONE+ HP Driver to install filing cabinet drawer rails

Step 4: Install Drawers into Modular Cabinets

After all the drawers were together, I installed them into the two other filing cabinet carcasses. 

Ryobi ONE+ HP Driver installing filing cabinet drawers

As a note, since file folders can get heavy, I made sure to install the slides with several screws in holes that won’t allow for vertical movement.  That way, when they’re weighted down, they shouldn’t sag causing misalignment.

Check out my drawer building guide for more information.

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Then, I cut and installed the 3/4″ plywood drawer fronts using 1 ¼” wood screws from the inside of the drawer boxes, leaving 1/8″ space around all sides.

Drawer front sizing diagram for modular filing cabinet drawers

Step 5: Add Top to Filing Cabinet Desk or Cabinets

The last thing to do before finishing was cut the top.

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Because these cabinets will be going side by side in my dad’s office, I cut a single top piece from ¾” plywood to stretch across the entire set.  However, if you are just building one cabinet or two, you can cut the top to fit your own needs.

Overall console cabinet dimensions with top and three bottom modular cabinets

I edge banded the top to cover the plywood edges–that’s an optional step.

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To finish, I gave everything a couple coats of clear poly (but you could stain/paint as you wish), then installed some modern handles onto the drawers. 

Close up of Ryobi ONE+ HP driver installing drawer pulls in filing cabinet

Then I set it up to stage in my garage.  I didn’t attach everything together yet because I will be loading these up to take to my dad’s shop.  I just needed some quick pics to share 🙂 haha.

Modular home office storage cabinets--two filing cabinets and a shelving unit set up as a single console cabinet

But, once you get them where they are going, you can simply screw the cabinets together (if placing them side by side), center the top in place and secure through the top supports of the cabinets with 1 1/4″ screws.

DIY filing cabinet desk put together

NOTE: If you load these drawers down with file folders, they could potentially tip over if you pull both drawers out at the same time.  I’d recommend anchoring them to the wall if that’s a concern.

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And now you have a modular desk idea that you can EASILY build and customize as you wish.  Shelves and drawers.  Just shelves.  Just drawers.  You could even cut some simple doors to go on those shelf cabinets, too to change things up even more.

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If you enjoyed this DIY modular filing cabinet desk, be sure to subscribe to my newsletter below so you don’t miss out on what’s next.  And pin this project for later for easier reference 🙂

Collage image for pinterest showing DIY file cabinet drawers open, exploded cabinet graphic and desk set up with a shelf and filing cabinet

Until next time, happy building 😊

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