How to Measure for a Driveway Gate: The Numbers a Fabricator Needs and How to Get Them Right

Every driveway gate that arrives and does not fit was measured. It was just measured in the wrong place - the old gate instead of the posts, one height instead of two, the concrete instead of the high point of the ground. This guide is the fifteen minutes with a tape measure that make the gate hang right the first time. You need a tape, a helper, a phone for photos, and a pen.

What you are actually measuring

A fabricator builds a gate to hang in an opening. The gate itself is narrower than that opening, because the hinges need room on one side and the latch (or the second panel) needs a gap on the other. Those clearances are the fabricator's job. Your job is the opening.

So the single most important number is post to post: the distance between the inside faces of the two posts the gate will hang between, measured where the gate will actually hang. Everything else - height, ground clearance, slope - refines that.

If you are replacing a gate, this is why you never measure the old one. It was built smaller than the opening by an amount you do not know, and ordering "the same as the old gate" gets you a gate that is smaller again.

Step 1: post to post, twice

Hook the tape on the inside face of one post and run it to the inside face of the other. Measure at about hinge height - roughly 3 feet up for a 5- to 6-foot gate - and write it down to the nearest quarter inch.

Now measure again near the top of where the gate will be and near the bottom. Posts lean. If the three numbers agree within half an inch, use the smallest. If they differ by more, note all three; a leaning post is worth knowing about before the gate arrives, and it may mean resetting it (the posts guide covers when a post is worth saving).

No posts yet? Decide the opening you want - the width guide sizes it by vehicle - and measure between the marks where the posts will stand. The gate's instructions will give you the exact post spacing to set.

Step 2: height

Measure from the ground to the top of the existing posts, or decide the height you want the gate to be. Five to six feet is the residential norm; local rules often cap front-yard gates lower, and the permits guide tells you where to check. Remember that the gate hangs above the ground, so the top of the gate is the gate height plus the ground clearance.

Step 3: the ground under the gate

This is the step people skip and the one that causes the most trouble. Run the tape - or a long straight board with a level on it - across the opening at ground level and note the highest point and the lowest point of the ground the gate will pass over. On a flat concrete driveway they are the same. On a crowned driveway the middle is higher than the edges; on a cross-slope one side is higher; on a driveway that rises toward the house, the ground climbs through the whole swing arc.

The gate's bottom rail has to clear the highest point everywhere it travels. Two to four inches above the high point is the usual target. If clearing the high point leaves a gap of eight inches at the low side, you have a slope problem, not a measuring problem - read the sloped driveway guide, because that usually means a slider, a cantilever, or a swing that opens the other way.

Step 4: the swing room

For a swing gate, stand at the opening and walk the arc each panel will travel: a quarter circle with a radius equal to the panel width, on the side the gate opens toward. Note anything inside it - a parked car, the garage door path, a planter, a slope that rises into the arc. For a two-panel gate, each arc is half the opening; that is often the difference between a gate that works and one that hits the car.

For a slider, measure the straight run of fence line beside the opening. A tracked slider needs a run at least as long as the gate; a cantilever needs about one and a half times the gate width.

Step 5: photograph it

Take four photos with the tape visible in at least one: from the street looking in, from the house looking out, and each post close up including where it meets the ground. A photo catches what a note misses - the lean, the crown in the driveway, the mailbox that is in the arc - and it is what our assistant uses to check your numbers before you order.

Writing it down

A complete measurement is six lines:

• Post to post at hinge height: ___ inches
• Post to post at top / bottom: ___ / ___ inches
• Gate height wanted: ___ inches
• Ground: high point ___ , low point ___ (and where each one is)
• Swing side and what is in the arc / slide run available: ___
• Photos: 4

That is everything a fabricator needs. In our configurator you enter the width and height in inches and the price updates for your exact size - a 160-inch gate costs what a 160-inch gate costs, with no stock sizes and no custom premium.

The mistakes that cost people a rebuild

• Measuring the old gate. Covered above, and still the most common one.
• One measurement. Posts lean and openings taper. Three heights, use the smallest.
• Measuring the concrete, not the ground. The gate passes over the lawn and the crown of the driveway, not just the slab under the tape.
• Forgetting the mirrors. A pickup is 6 feet 8 inches at the body and over 8 feet at the mirrors; the width guide has the table.
• Ignoring the turn. A driveway that meets the street at an angle needs a wider opening than the vehicle suggests.
• Guessing the slope. "It's pretty flat" has produced a lot of gates that drag. Put a level on a board.

If your numbers are in hand, they go straight into the configurator. If something above does not match your driveway - an odd angle, a post you are not sure about, a slope you cannot read - send the photos to the gate expert and ask; it will tell you what to measure next.