Use the following estimates to determine the approximate amount of boulder stone needed for a retaining wall. Coverage varies based on boulder size, shape, placement, and wall design.
Estimated boulder coverage by size
- 6–12 in. (15–30 cm) boulders
- 1 U.S. ton (2,000 lb): Approximately 25 linear ft (7.6 m)
- 1 metric ton (1,000 kg): Approximately 27.6 linear ft (8.4 m)
- 12–18 in. (30–45 cm) boulders
- 1 U.S. ton (2,000 lb): Approximately 10 linear ft (3.0 m)
- 1 metric ton (1,000 kg): Approximately 11.2 linear ft (3.4 m)
- 18–24 in. (45–60 cm) boulders
- 1 U.S. ton (2,000 lb): Approximately 5 linear ft (1.5 m)
- 1 metric ton (1,000 kg): Approximately 5.6 linear ft (1.7 m)
- 24–36 in. (60–90 cm) boulders
- 1 U.S. ton (2,000 lb): Approximately 2 linear ft (0.6 m)
- 1 metric ton (1,000 kg): Approximately 2.3 linear ft (0.7 m)
Important: These are general estimating guidelines, not guaranteed coverage rates. Actual stone requirements depend on boulder dimensions, wall height, number of courses, and installation methods. Consult an experienced contractor when determining final material quantities.