Gate width calculator
Turn your clear gate opening and hinge clearance into the gate panel width, in inches and feet, with the math shown.
Gate width
Enter your measurements and the result updates as you type.
Overview
The opening in the fence and the gate panel that swings inside it are two different numbers: the panel has to be built a little narrower than the post-to-post opening, with a small clearance gap on each side, so the leaf can swing without dragging on either post. This calculator converts the opening and that clearance into the panel width you actually order.
With a 4 foot opening and an inch of clearance per side, the panel comes to 46 inches: 48 inches for the opening minus 2 inches total clearance, the result shown in both inches and feet.
Common mistakes
- Ordering a gate panel the exact width of the opening, which leaves no room to swing and binds on both posts the first time the wood swells.
- Adding the clearance to the opening instead of subtracting it, which orders a panel too wide to fit between the posts at all.
- Applying clearance to only one side, which leaves the latch side binding on its post.
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In-depth guides
Frequently asked questions
How wide is a gate for a 4 foot opening?
With 1 inch of clearance per side the panel is 46 inches: 48 inches for the opening minus 2 inches total clearance, shown by the calculator as 3.83 feet.
What is the gate width formula?
Multiply the opening in feet by 12 to get inches, then subtract the clearance per side times two. A 4 foot opening at 1 inch per side is 4 times 12 (48) minus 2, for a 46 inch panel.
Why does the gate need clearance at all?
Wood and vinyl swell and move with the weather, so a panel built the exact width of the opening will bind on the posts within a season. A small gap per side keeps the leaf swinging freely regardless of moisture and hinge wear.
Why is the panel smaller than the opening, not bigger?
The panel has to fit and swing inside the post-to-post opening, not cover it from the outside, so it is built narrower than the opening by the clearance amount. A panel built wider than the opening simply will not fit between the posts.
How does a double gate use the width?
The opening is split across two leaves that meet at the center with a small meet gap, so each leaf is roughly half the opening minus its share of hinge and meet clearance. See the double gate calculator for the exact per-leaf math.
Is an inch per side always right?
One inch is a common starting figure for residential wood and vinyl. Heavy gates swinging long spans, gate posts out of plumb, or tight concrete sills can call for more, and the calculator accepts any clearance you enter.
Should the hinge side and latch side have the same clearance?
Usually, to keep the gap even around the panel. A bare extra fraction on the hinge side and nothing on the latch side will still bind at the latch when the wood absorbs moisture.
Does gate width change the gate post size?
Indirectly: wider panels are heavier and put more load on the hinge post, which is why drive gates use double leaves and upsized posts. This calculator sizes the panel; the post sizing and set depth are handled by the gate and post calculators.