Which way should the diagonal brace go on a gate?

The diagonal brace should run from the bottom hinge corner to the top latch corner, forming an upward slope from hinge to latch side. This transfers the weight of the gate back to the hinge post. If installed the wrong way, the gate will sag.

How wide should a pedestrian gate be?

A standard pedestrian gate is 900mm (3ft) wide, which allows comfortable single-person passage. For wheelchair access, allow 1000mm minimum. Driveway gates should be at least 2.4m (8ft) wide for a single car, or 3.6m for comfortable two-way access.

How do I stop a wooden gate from sagging?

Ensure the diagonal brace runs the correct way (bottom hinge to top latch). Use a substantial hinge post set at least 600mm deep in concrete. Three hinges distribute weight better than two for heavy gates. Add a gate wheel for extra support on large gates.

What size posts do I need for a gate?

For a pedestrian gate, use 100 x 100mm posts minimum. For double driveway gates, use 125 x 125mm or 150 x 150mm posts. Posts should be set 600mm deep in concrete. The hinge post takes most of the load and should be the most solidly fixed.

WoodCalcs.uk

Gate Calculator — Timber & Hardware for Gates

Calculate timber and hardware quantities for garden and driveway gate construction.

Gate TypePedestrian = single leaf; Double = two leaves for a driveway; Side access = narrow path gate

StyleClose board = boards butted with no gaps; Palisade = spaced pickets with gaps; Ledged & braced = traditional framed gate with horizontal ledges and a diagonal brace

Gate Width (total opening)

Total clear opening width between the posts (e.g. 900mm for a standard pedestrian gate)

Gate Height

Overall height of the gate leaf (e.g. 1800mm for a 6ft gate)

Board Width

Width of each board

Timber Price per Metre (optional)

Enter your supplier price per metre

How We Calculate This

This calculator estimates timber and hardware for a traditional ledged and braced gate.

Board calculation

Vertical boards = ceil(Gate width / (Board width + Gap))

Close board style has no gaps. Palisade style includes 25mm gaps between boards.

Diagonal brace

Brace length = sqrt(Width² + Height²) (Pythagoras theorem)

This is the corner-to-corner diagonal of the full gate leaf, so it is a generous ordering length. The finished cut runs between the inside faces of the top and bottom ledges and will be slightly shorter — cut it to fit on assembly.

Posts include 600mm extra length for burial in the ground with concrete.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.