One of the most common mistakes people make when ordering a driveway gate online is measuring the wrong thing. They measure the distance between fence lines, or the width of the road at the entrance, or some other number that sounds right but isn’t what the gate actually needs to fit. Here’s how to do it correctly.
What You’re Actually Measuring: The Rough Opening
The “rough opening” is the clear space between your gate posts — post face to post face. This is the number that determines your gate width. It’s not the distance between fence panels, it’s not the driveway width at the curb, and it’s not the distance between the outsides of your posts. It’s the clear span between the inside faces of the posts where the gate will hang.
Measure this at three heights: near the ground, in the middle, and near the top. Posts settle and lean over time, so the opening isn’t always perfectly consistent top to bottom. Use the smallest of the three measurements as your gate width to ensure the gate fits at every point.
Gate Width vs. Gate Panel Width
Your gate width should be equal to — or very slightly narrower than — your rough opening. A 12-foot rough opening typically takes a 12-foot gate. You don’t want to size up and then force it to fit, and you don’t want to leave so much gap that the gate looks sloppy or doesn’t latch cleanly.
For double swing gates, the total gate width is split between two panels. A 12-foot opening gets two 6-foot panels. This matters when you’re spec’ing hardware like hinges and drop rods, which are sized to the post diameter, not the overall gate width.
Gate Height
Gate height is measured from the ground clearance point (the lowest point the gate will pass over as it swings or slides) to the top of the frame. For flat driveways, this is straightforward — measure from grade to your desired height. For sloped driveways, measure at the point where the gate arc will be closest to the ground, which is usually mid-swing.
Common residential heights are 4, 5, and 6 feet. Commercial properties, privacy applications, and security installations typically run 6 to 8 feet. Remember that a taller gate is a heavier gate, which affects post sizing, hinge selection, and opener specifications.
Post Diameter Matters for Hardware
If you’re ordering hinges or hardware at the same time as your gate, you’ll need to know your post diameter. Bulldog hinges, for example, come in 2-3/8” and 2-7/8” sizes, which correspond to standard fence post diameters. Measure the outside diameter of your gate post and match accordingly. Using the wrong size hinge is one of those mistakes that seems minor until you’re trying to make it work on-site.
A Quick Measurement Checklist
- Measure rough opening (post face to post face) at three heights — use the smallest number
- Decide gate height based on grade and intended use
- Note whether your driveway is level, sloped toward the gate, or sloped away
- Measure post outside diameter if ordering hinges
- For slide gates, measure available clearance on the slide side (needs to be at least equal to gate width)
If you’ve got your numbers and you’re ready to find the right gate, browse our driveway gate collection or reach out and we’ll help you configure the right option for your opening.