This driveway gate width calculator sizes your gate 7 ways: opening width for your vehicle, single vs double vs slide, swing-clearance arcs, height, post and footing specs, opener class, and a full material plus cost takeoff.
Recommends a clear opening (net, after posts and hardware) for your widest vehicle.
Compares gate types against your space, slope, and opening width.
A gate swing clearance calculator: arc radius, swept area, and ground clearance over your driveway grade.
Height by purpose, with slope compensation and ground-clearance guidance.
Gate posts carry far more leverage than fence posts — size them up.
Matches opener class to leaf weight and length (UL 325 classes).
Frame, pickets, hinges, posts, concrete, opener — priced as US hardware-store bands (2026).
Match the gate to your driveway and your widest vehicle. A 12 ft driveway with an SUV or pickup needs a 12–14 ft clear opening — a 13 ft opening (our worked example) is a common pick. Standard driveway gate sizes run 10, 12, 14, 16, 18, and 20 ft: a 12 ft driveway gate is the most common single-car pick, a 16 ft driveway gate covers two cars or wider driveways, and RV gate width requirements call for 16–18 ft of clear opening. Fire-code access needs 20 ft unobstructed. Always measure the net clear opening (between posts, minus hardware), not the nominal leaf size.
For a 13 ft opening: a single swing gate is one 13 ft leaf that needs 13 ft of clear swing depth; a double swing splits it into two 6.5 ft leaves needing only 6.5 ft of depth and half the weight per leaf; a slide gate needs no swing arc but wants 19.5 ft of side rollback space (1.5× the opening). Double driveway gate dimensions are sold by clear opening — our worked example is a 13 ft double (two 6.5 ft leaves), and standard nominal doubles run 12/14/16 ft. Pick single swing for openings up to 14 ft on flat ground, double swing for 14–18 ft or a balanced look, and slide or cantilever when the driveway slopes into the swing path or side space is tight. Mode 2 above lays out the sliding gate vs swing gate pros and cons side by side: slide gates need no swing arc but want a clean track and 1.5× side space; swing gates are simpler and cheaper but need clear ground to swing into.
The swing arc radius equals the leaf width — a 6.5 ft leaf sweeps a quarter-circle of 6.5 ft radius and needs 6.5 ft of clear depth to open 90°. Keep that arc free of cars, planters, and walls. Also check the ground: the gate bottom must clear the highest point in its path by at least 2 in. On our example's 2% grade that works out to 3.56 in of needed ground clearance. Gates must swing inward, never over a sidewalk or public road.
Four feet is the minimum effective height; 5–6 ft is the sweet spot for security and privacy (our example uses a 6 ft privacy gate), and decorative or pet gates often sit at 4–5 ft. Add a foot if the driveway slopes steeply into the gate. Every extra foot of height adds weight and wind load, so size the posts, hinges, and opener up with it.
Gate posts carry far more load than fence posts. For a 13 ft double swing gate with 6.5 ft leaves, use 6×6 wood or 4 in steel posts set in 18 × 18 × 36 in concrete holes — that 36 in gate post footing depth is the minimum, about 12 sixty-pound bags of concrete per post (24 for the pair). Longer or taller gates step up to 5–6 in steel posts in 20–24 in holes with 42–48 in of gate post footing depth. If you are still unsure how much concrete for gate posts, run mode 5 above — it converts your hole size to cubic feet and 60-lb bags automatically. Set posts to the highest ground point in the swing arc, keep 2 in clearance from any structure, and call 811 before you dig.
Two to four inches of gate ground clearance is typical. The critical rule from gate install guides: set the hinge posts so the gate clears the highest elevation anywhere in its swing path by at least 2 in — on a 2% grade with a 6.5 ft leaf, the far edge rises 1.56 in, so you need 3.56 in total. If the math demands more than about 6 in, the gap looks bad and pets or children can slip under — switch to a slide gate or regrade the driveway instead.
Match the opener to leaf weight and length, not just the opening — check the gate opener weight capacity against your heaviest leaf first, then its rated leaf length; both specs have to cover your gate. Our example leaf (6.5 ft × 5 ft steel ornamental, 292.5 lb) fits a DIY swing-arm kit rated up to 300 lb / 12 ft per leaf. Bigger leaves step up to mid-duty operators (up to 18 ft / 1,600 lb) or heavy-duty (up to 22 ft / 2,000 lb) under UL 325 classes I–IV. Match the gate operator duty cycle UL 325 class to your site — high-cycle commercial entries need a continuous-duty rating. Double swing needs a dual-arm pair; slide gates need a slide operator, never a swing arm. The swing arm vs slide gate operator rule is simple: swing arms only ever drive swing leaves, slide operators only drive slide gates. In the solar gate opener vs wired debate, go solar (10–30 W panel plus battery) when trenching power costs more than the panel; otherwise wired AC with battery backup is the most reliable. UL 325 requires monitored entrapment protection, and pedestrians need a separate walk gate.
For the worked example — a 13 ft double swing steel gate, 6 ft tall, with a DIY opener — hardware and materials run about $1,601.50 to $3,001: frame tubing, pickets, 4 heavy hinges, latch and lock, 2 steel posts, 24 bags of concrete, the opener kit, and remotes with a keypad. Professional installation typically adds $500–$2,500. Prices are US hardware-store bands, 2026.
The fence calculator's Gates tab is a material takeoff: you enter a gate count and it lists hardware for a fence project. This tool sizes the gate itself — opening width for your vehicle, single vs double vs slide, swing arcs and ground clearance, height, post and footing specs, opener class, and a full material plus cost takeoff. Use this tool to design the gate, and the fence calculator to plan the fence run around it.
A cantilever gate rides on trolleys along a rear-mounted rail with a counterbalanced tail — no ground track to jam, so it keeps working on gravel, dirt, or snow, but the hardware costs the most. A tracked sliding gate runs on a ground track and needs about 19.5 ft of side rollback space for a 13 ft opening, versus about 18.2 ft for a cantilever; keep the ground track clear of leaves and ice or the gate stalls. Choose cantilever where the driveway is unpaved or a track would collect debris, and a tracked slide where side space allows and budget matters.
Set the gate line back so a waiting car fits between the gate and the road or sidewalk — fire-district guidance (MidStar) calls for a minimum 30 ft setback from the curb line to form a stacking lane, and at least 20 ft of unobstructed clear width for fire access. Gates must swing inward, never over a sidewalk or public road. Local codes, permits, and HOA rules may require more — check them before you pour concrete.
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