How to Measure a Drawer Slide: A Step-by-Step Guide

Whether you’re renovating an old kitchen or setting up a new workstation, it’s important to get the drawer dimensions just right. Otherwise, you might end up with a creaky and wobbly mess that frustrates you every time you have to use it. A good drawer slide should come with detailed instructions on how to mount it, but you’ll have to make the call on selecting one that’s the correct size based on your drawer and cabinet dimensions.

In today’s step-by-step guide, we’ll show you how to bypass all potential headaches and choose the right size drawer slide in 5  easy steps! So without further ado, let's get started.

Measuring a Drawer Slide In 5 Simple Steps

Before we get started, it’s important to explain a couple of things. First of all, the length of the runner or guide rail on a drawer slide is usually 15 to 16 millimeters less than the total length of the slide. When you select a drawer and slide combo, you need to make sure that your drawer length matches up with that of the runner, and not the total slide length. This is crucial if you’re going with an undermount slide, and we’ll explain why in a short while. Okay, let’s continue-

Step 1: Preparation

Make sure you’ve got your measuring tape and marker/ pencil ready before we begin.

Step 2: Identify The Type Of Drawer Slide (Undermount vs Regular)

Next, we must understand the difference between an undermount and regular slides. Regular slides mount to the side of your drawer, and they’re about half an inch thick. So you’ll need 1 inch of clearance between your drawer and the cabinet- a half inch on either side.

In comparison, undermount slides have most moving parts slung underneath the drawer and therefore require much less clearance on the sides. However, they do require more space on the bottom.

And this is the really important part- with an under-mount slide, you must get the drawer depth lined up exactly to match the slide runner length. So if a slide is 15 inches long, your drawer must be exactly 15 inches deep. That’s because an under-mount slide fits into recesses on the floor of your drawer and hooks into the back. If your drawer is longer than the slide, the hooks won’t be able to clear it. If it’s shorter, they can’t reach into the mounting holes.

With regular drawer slides, you can give or take an inch or half. If you’ve got a 15-inch slide and a 16-inch drawer (assuming there’s still enough clearance between the back of your drawer and the cabinet) you can still mount the drawer to this slide. However, it won’t extend all the way out so you’ll be wasting the potential benefits of a full-extension slide. Conversely, if the drawer is slightly shorter than the slide, you’ll get an overextension where the back of the drawer hangs out in front of the cabinet.

Step 3: Measure the Drawer Width

Now, it’s time to begin the actual measurements. Let’s start with the width of your drawer. Take your tape measure, line it up with the cabinet frame, and measure the opening. Make sure it’s parallel to the floor, or else you’ll get an incorrect figure. Some of you might have a cabinet without a face frame, and we’ll discuss how to deal with that in a later section. For now, let’s assume you’ve got a typical European-style frameless cabinet which is the norm in most modern kitchens.

Take the width you got from your tape measure, and subtract 1 inch (or 25mm) if you’re going to use regular slides. Because each one should be about 0.5 inches thick. As an example, if your cabinet opening is 17.5 inches wide, your drawer width should be 16.5 inches to accommodate the tracks on either side.

For undermount slides, which have thinner mounts, you should subtract 5/8 inches from the width of the cabinet opening. Or 16 millimeters. So if you have a 17.5-inch cabinet opening, your drawer width will be 16  inches, or 16.87 inches.

Step 4: Measure the Drawer Height

Drawer height is next, and you don’t want to use every available bit of space because otherwise, you’ll end up with a drawer that rubs against the floor of the cabinet. It’s a good idea to leave about a quarter inch on both the top and bottom. So once again, take your tape measure and find out the height of your cabinet opening. Then, subtract half an inch.

With under-mount slides, you’ll need more clearance at the bottom. Some cabinet makers will also put a recess in the floor of the cabinet or drawer box to accommodate the tracks. Depending on your drawer slide manufacturer, you might have to leave anywhere from 14 to 16mm of clearance between the drawer floor and cabinet frame (about 9/16 inches).

Step 5: Measure the Drawer Depth

Finally, it’s time for the most important measurement- drawer depth which correlates to the length of your runners. Remember, you’re measuring the runner which is the telescoping rail part of the slide and not the entire thing. Roll out your measuring tape and measure the distance between the back of your cabinet and the face. Then, subtract an inch for clearance. If you’re going with an overlay layout in which the drawer face is outside the frame, this is your length. But if you have an inset drawer face, you must subtract the thickness of this face from your measurement.

For example, let’s say you have a cabinet depth of 20 inches. Subtract 1 for clearance if you have an overlay arrangement, and you have a 19-inch drawer depth. If you have a drawer box with an inlaid front that’s 0.75 inches thick, subtract that from the measurement. So now, you’re left with 18.25 inches of depth.

Undermount drawer slides typically come in size increments of 3 inches. So the closest we have is an 18-inch drawer, which matches up perfectly with our requirements. Regular drawer slides are available in 2-inch increments, and we can also get an 18-inch drawer of this type.

With undermount drawer slides, your drawer box and runner length must match up perfectly otherwise you can’t mount the rear hooks. With side-mounted drawer slides, you’ve got a bit more leeway. Undermount slides give you slightly more drawer width but you lose some height in exchange, so the internal volume balances out to be similar between regular and under-mount slides.

Inset Drawer Font vs Overlayed Drawer Front

With an inset or inlaid drawer front, the face of the drawer meshes seamlessly with the rest of the cabinet. This is the style we’re seeing in modern home furniture as it’s sleek and elegant, without drawing too much attention to itself. But you must subtract the thickness of the drawer face from your calculations while deciding which drawer slide to buy. If you don’t, you’ll end up with a slide that’s too long and your drawer will extend beyond the cabinet face when you pull it out, which will look bad.

An overlayed drawer face requires no additional calculations, you just measure the cabinet depth and subtract an inch for clearance at the back. That’s it.

Do you have a frameless cabinet?

With a frameless cabinet, your drawer's width will be the width of the cabinet opening minus 1 inch (for regular slides). Undermount slides have slimmer mounts, so you subtract 3/8 inches from the width instead of 1.

If you have a cabinet with a face frame, you’ll have to measure the width between the face opening instead of the actual cabinet width underneath.

Which Screw Holes To Use?

Drawer slides come with multiple mounting points. Some have perfectly circular openings while others have rectangular shapes so you can adjust the slide for height and length. For everyone except professionals, we recommend mounting your slides with rectangular screw holes so you can make minute adjustments to the drawer orientation without having to drill new holes in your cabinet or drawer box.

Conclusion

Here is some final advice: Always measure both sides of your cabinet for width and height. Assuming that measurements for one side will be accurate for the other might result in improper fits, especially with custom furniture with non-standard dimensions. Always get your drawer slides from reputable drawer slide suppliers. Quality matters, and is often worth the slight increase in price for peace of mind in the long run. But since Tallsen has a diverse array of high-quality steel drawer slides that use ball bearings, you should have no problem! Just browse our catalog and place the order for a drawer slide that fits your size requirements. And yes, we accept bulk orders if you’re a cabinet maker or dealer.