Full Extension Drawer Slides: Choosing the Right Size

A white piece of particle board furniture with drawer slides.
What You'll Need
Measuring tape
What You'll Need
Measuring tape

Full extension drawer slides have become popular with both builders and homeowners alike in recent years. They are just the thing when every square inch of a drawer is used for storage and you need to be able to access all items in a drawer. But how can you be sure to purchase the right size?

The Importance of Measuring Accurately

If you have high-quality full extension drawer slides that are properly fitted and measured, you will get years of life from them. They will extend the life of your cabinetry as well. However, if you get poorly fitted slides, they will warp the cabinets as well as jamming the slides themselves. So spend a little bit of extra money and save yourself the headache.

Proper measuring is just as important as quality. Full extension drawer slides come in measurements from 8 inches to 28 inches and in widths of 250 mm to 600 mm, so you will find the right slide for your drawer with a little persistence.

Measure the Drawer

When you measure the drawer, remember to remove it completely from the existing cabinet or dresser. Depending on the current drawer glide (if this is a replacement project), this may require some manipulating. Lift up on the front of the drawer, and if that doesn’t work, try lifting on the back of the drawer to lift it out of the current glides. It may be easier to measure the drawer if the old glide hardware is removed, but it is not necessary.

Measure the drawer carefully and accurately from the front of the drawer box to the back. Do not include the false front in your measurement. If you haven’t worked much with drawers and glides, you may not realize the drawers are made separately from the false fronts. You can replace and exchange just about any front onto a drawer box.

Lastly, measure how wide the cabinet or dresser's drawer opening is and compare it to how wide the drawer itself is. If there's a 1/8 inch difference between those two measurements, full extension slides will work fine. If the difference is a little more or a little less than 1/8 of an inch, you'll need to adjust the cabinet or dresser.

Measure Inside the Cabinet

You should also measure inside the cabinet and look for any extensions, bolts, wood pieces, or other obstructions that might interfere with the operation of the drawer glide. If you are replacing other glides with a full extension drawer glide, then you may find some problems.

Remember that full extension drawer glides are side-mounted, so if you had a bottom mount glide previously, it will not have the same fit.

Measure Clearance

If you are moving from wood glides or a bottom glide to full extension drawer glides, you’ll need to measure and see if there is enough clearance to handle the side mount glides. You need half an inch on each side of the drawer box in order to mount the glides. So you should measure the width of the box from outer edge to outer edge, then the interior of the cabinet and be sure you have the needed inch of clearance.

Choose the Glides

If you have the proper clearance and no obstructions in the box, then choose the glide based on your numbers. If your drawer box measures 15 inches, you can get a 15-inch slide. If the measurements are slightly off—in other words, if there is no full extension drawer slide in your drawer’s size—then purchase the next smaller size glide. If you purchase one that is even slightly too large, you’re likely to have problems with the drawer closing.

Always double-check your measurements for this project so you don't end up wasting time with the wrong size of glide. Take it slow and steady rather than rushing through, and you should have little trouble.