Timber retaining wall quantity calculator

Count actual timber dimensions

Nominal timber dimensions may differ from the actual finished size. Enter the actual timber length and installed course height. The example starts with an 8-foot timber and a 5½-inch course height; check your supplier’s product before using either number.

The model rounds the timber count in each course and the number of exposed courses upward, then adds buried courses and cutting allowance. Cut-off reuse, staggered joints and posts can change the order schedule.

Order timbers = ceil(ceil(run ÷ timber length) × (ceil(exposed height ÷ actual course height) + buried courses) × (1 + waste/100))

Anchors and fasteners need a design

The calculator does not choose deadmen, anchors, posts, spikes, screws or connection spacing. A fixed “one anchor every few feet” rule is not a safe substitute for a timber wall design.

Timber treatment, ground-contact suitability, connection durability, drainage and the planned service life need separate review. Use the selected product documentation and local design requirements.

Use the list for a supplier quote

Timbers can have minimum order sizes and delivery requirements that differ from block pallets. The tool reports individual timber quantity. The entered unit price is an example and should be replaced with a local quote.

Base, drainage and pipe remain editable planning quantities. They do not establish that a timber wall foundation or drainage detail is sufficient. Print the assumptions and attach the construction drawings when requesting an installation quote.