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What Size Drawer Slides Do I Need? DIY Guide (2021)

When deciding what size drawer slides are needed for a cabinet or furniture project the best place to start is with the depth of the cabinet. But with drawer slides it is not just the length of the slide that matters, it is also the thickness or “side clearance”. 

Which makes choosing drawer slides a bit confusing.

But by understanding the basic features of a drawer slide it is (with a little effort) easy to get to the best drawer slide for your project.

With that, the following factors will determine your drawer slide size:

  • Drawer depth – the length of the drawer slide is typically 1-inch less than the depth of the cabinet and rounded DOWN to the closest even increment.
  • Cabinet construction – a face frame cabinet requires at least 1-inch of depth clearance to support rear mount brackets; while a frameless can be as little as 1/8-inch.
  • Drawer mounting location – for side mount slides a 1/2-inch side clearance is standard, but for undermount drawer slides a slightly shorter slide with less side clearance is required.
  • Weight capacityheavy duty slides with over 150-pounds capacity often require up to 3/4-inch of side clearance.

New Construction Drawer Sizes

Perhaps your project hasn’t taken shape and you are looking to order your drawer slides so they are ready when you are. 

In this case, the task might be a bit more difficult as you may not have assembled the cabinet or furniture box. But you should, at least, know the depth of the final assembled box.

Standard Drawer Slide Sizes for Kitchen Cabinets

Drawer slide sizes for kitchen cabinets

Most kitchen drawer slides are 21 to 22-inchdes in length

First, almost all kitchens are made with 24″ final depth cabinets to support standard sized countertops.

Which makes lengths of drawer slides for kitchens easy (and side clearance too).

By slide type, the following is the rule of thumb:

  • Side and bottom mount drawer slides are almost always 22″ and have a 1/2″ side clearance. Have a face frame cabinet? You’ll need rear mount brackets too.
  • Undermount drawer slides are 21″ and have a custom drawer width

Drawer Slide Lengths for Bathroom Vanities

Bathroom Vanity Drawer Slide Length

Most vanities have 16 or 18-inch drawer slides.

Similar to a kitchen cabinet, and with the standard vanity top depth at 21-inches, you’ll find the finished depth of vanities mostly support a 16 or 18-inch drawer slide.

Why the variation? Well, it depends on the overhang and style of vanity top. While some cabinets push to 20″ deep (and thus support an 18″ slide), others prefer more overhang and require a 16″ slide for the best depth.

The best way to decide? Work backwards from the depth of your vanity top. While most homeowners prefer at least 1-inch of counter overhang, 3/4-inches for the drawer front and have 1/4 to 3/4″ in the back (up to 2-1/2 inches) you’ll be fine at 18-inches for a frameless cabinet and tight for a face frame cabinet.

Furniture Drawer Slide Lengths

So by now you’ve probably got the picture on choosing a slide length for new construction. For furniture projects follow the same rule of thumb:

  • Face frame designs subtract 1″ from depth of the finished cabinet and round down to nearest even length
  • Frameless designs can be measured tighter, but its best to lay out and if in doubt go a little shorter than longer.

Soft Closing vs. Self Closing Drawer Slides

As you are realizing drawer slide lingo is a bit confusing.

And one of the more confusing points is the difference between soft and self closing:

  • Self closing simply means the drawer will use gravity to pull the drawer shut. But it WILL NOT prevent the drawer from slamming.
  • Soft closing drawer slides will both hold a drawer shut AND use a damper technology to prevent the drawer from slamming.

All of which has led most new kitchens and projects to use soft closing slides. Because nobody likes to hear slamming cabinet drawers.

And, when it comes to deciding the size of drawer slides there is rarely any difference in the lengths.

Measuring Drawer Slides for Existing Drawers

Side Mount Drawer Slide Length

One way of quickly updating your drawers is to replace the drawer slides with improved performing slides. 

But, that may mean switching from a center-mount slide to a side mount drawer slide. Which, as you might know, creates a new measuring question: what size drawer slide do I need for a retrofit?

Side Mount Drawer Side Lengths and Extensions

If this is your first exposure to drawer slide mechanics a good place to start is with a side mount drawer slide.

Not only are these slides strong, they are also top performing slides when properly installed:

  • Easy to mount
  • Ball bearings for smooth action and high weight loads
  • Standard 1/2-inch side clearance
  • Full extension features allow access to the back of the drawer

Lastly, side mount slides are available in 2″ increments from 10″ up to 72″ and make them a great fit for any cabinet or furniture.

Bottom Mount (Epoxy) Drawer Slides

While a true count would be hard to obtain, there are likely billions of bottom mount drawer slides powering cabinets and furniture. And, this is because these slides are inexpensive and have (generally) good performance.

When it comes to picking sizes, though, you’ll be looking at slides between 12-22″ in length. Why so short? Well, their design is centered on narrow tracks for epoxy wheels and doesn’t stay rigid over longer lengths.

Undermount Drawer Slide Sizes

Undermount Drawer Slide

Of all the types of drawer slides, there is none more finicky than the TOP performing undermount drawer slides.

Why? Well, consider:

  • Undermounts require a custom side clearance to support the thickness of the drawer side
  • Most undermount slides are grooved into the drawer bottom 
  • And, for face frame cabinets, require a rear mounting bracket

So, if your goal is replacing undermount drawer slides you’ll want to replace them “like for like” with the same part number and length. Unfortunately, upgrading a side mount drawer to undermount is rarely possible.

The good news? Most undermounts come in limited lengths of 12″, 15″, 18″ and 21″. Which should make measuring relatively easy.

Frequently Asked Questions

Frequently Asked Questions

How much space does a drawer slide need on the side?

Most drawers are built to support a 1/2″ of clearance on each side of the drawer. However, heavy duty drawer slides will often take from 0.7 to 0.75 inches and undermount slides a custom amount less than 1/2″.

Can drawer slides be shorter than the drawer?

Yes, a drawer slide can be shorter than the drawer. However, the drawer will not fully open and the distance from the back of the slide mounted on the drawer to the rear of the drawer will be lost for accessibility.

What size drawer slides are used for a 24-inch deep cabinet?

For face frame cabinets the standard drawer slide length is 22″ to allow for use of a rear mounting bracket. The same is generally true for frameless cabinets as you need to have at least 1″ of space for the drawer front and rear of the cabinet.


As you make a final decision on the size of your drawer slides be sure to consider using soft close drawer slides (not self close), drawer slide jigs and the right cabinet screws for your project.

Last update on 2021-12-05 at 09:23 / Affiliate links / Images from Amazon Product Advertising API

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