Gate Width and Swing Clearance Calculator
Calculate the required gate width for a passage opening and determine the swing clearance arc radius needed for single or double gates.
Minimum clear width needed for passage (e.g. 36" for ADA pedestrian, 96" for vehicles)
Width of each post or frame member that reduces the clear opening
Distance the hinge pin sits proud of the post face; adds to swing radius
How far the gate opens (90° standard; 180° for full fold-back)
Thickness of the gate leaf (affects clearance at the latch post)
Formulas Used
Rough Opening = Clear Opening Width + 2 × Post Width
Leaf Width = Rough Opening ÷ Number of Leaves
Swing Radius (R) = Leaf Width + Hinge Offset
Arc Chord = 2 × R × sin(θ ÷ 2) where θ = swing angle
Lateral Clearance = R × sin(min(θ, 90°))
Depth Clearance = R × (1 − cos(θ))
All trigonometric functions use angles converted to radians (θrad = θ° × π / 180).
Assumptions & References
- The hinge pin is treated as the fixed pivot point; the gate leaf is modelled as a rigid rod of length equal to the leaf width.
- For double gates, both leaves are assumed equal in width (rough opening split evenly).
- Post width is subtracted from both sides of the rough opening to yield the clear passage width.
- Hinge offset (pin proud of post face) is added to the swing radius because the gate tip travels a larger arc than the leaf width alone.
- Lateral clearance uses the smaller of the actual swing angle and 90°, because the maximum perpendicular reach of the tip occurs at 90° and does not increase beyond that angle.
- ADA / ICC A117.1 recommends a minimum 32" clear width for accessible pedestrian gates (36" preferred).
- Residential vehicle gates typically require 10–12 ft (120–144") clear; commercial/RV gates 14–16 ft.
- IBC Section 1010 and NFPA 101 govern egress gate requirements for occupancy-specific applications.
- No allowance is made for gate sag, wind load deflection, or hardware protrusions beyond the hinge offset entered.