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Fence Gate Clear Opening: Dimensions for Custom Orders

For a custom gate, tell us the usable opening you need with the gate in its specified open position. A nominal leaf width or outside post dimension cannot establish that passage. This guide separates the dimensions a buyer should provide from the leaf, post and hardware dimensions that must be coordinated before fabrication.

By FencingWise Editorial Team · Updated 3 November 2026.

Four widths that often get confused

Dimension What it measures
Leaf width The physical moving gate leaf, using the stated frame reference
Clear distance between post faces The space between the inward faces of the gate posts
Usable clear opening The unobstructed passage with the gate in the specified open position
Overall assembly width The complete width across the stated outer assembly references
Black double-leaf mesh gate installed between two gate posts
The leaves and the gap between the post faces are separate dimensions.

Hinges, open leaves, catches and other projecting parts can reduce the usable opening. The opening angle and the position at which clearance is measured therefore belong beside the dimension.

Worked example: two leaves between posts

Take an illustrative double-leaf arrangement with 4,000 mm between the inner post faces. Assume:

  • Left hinge-side gap: 20 mm.
  • First leaf width: 1,970 mm.
  • Meeting gap: 20 mm.
  • Second leaf width: 1,970 mm.
  • Right hinge-side gap: 20 mm.

The closed arrangement adds up to 4,000 mm. With two 100 mm wide posts, the outside-to-outside post dimension is 4,200 mm.

Now assume that, in the specified open position, the leaf and hardware project 30 mm into the passage from each post face. The usable opening is 4,000 − 30 − 30 = 3,940 mm.

All values are hypothetical geometry, not recommended clearances, post sizes or a FencingWise gate specification. The example shows why a nominal “4 m gate” may not provide 4 m of unobstructed passage.

Put the open position on the plan

Send both the closed elevation and an open-position plan for quotation review. Show swing direction or sliding travel, the required opening position and any fixed obstruction that cannot move. Where a replacement gate uses existing posts, include measured faces and hardware projections. The fabricator needs these constraints to develop the leaf arrangement; vehicle swept-path and accessible-route acceptance remain with the project designer.

Also identify the finished ground reference. A gate can provide the required width while a raised surface, channel or step creates a different access problem. For vehicles entering at an angle, the site designer needs the swept path, not just a straight width measurement.

Double-leaf mesh gate viewed with adjoining fence and paved passage
Show the actual passage and the open gate position on the plan.

Write the enquiry around the required result

Write the required unobstructed width and the position in which it must be achieved, then mark the fixed site dimensions separately. Ask the proposed drawing to return that clear-opening dimension, the leaf sizes and the hardware allowance together. Approving only a gate’s overall size can leave a custom-made assembly that fits between the posts but does not provide the passage the buyer ordered.

A clearer enquiry says: “Required usable opening: 4,000 mm, measured in the specified fully open position,” accompanied by the layout. The supplier can then show the leaf widths, post positions and hardware needed to achieve that dimension.

For an existing entrance, mark which dimensions cannot change. Do not infer the new leaf width by copying the old nominal gate name. Use the gate drawing checklist to keep opening direction, hardware and revisions with the dimensions.