Calculate excavation volume in cubic yards for rectangular pits and trenches. Includes sloped wall calculation for OSHA-compliant trenching and truck load estimates.
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Shop Express Tools →An excavation volume calculator is essential for bidding earthwork jobs and planning equipment and trucking. Rectangular pit volume is simply length × width × depth ÷ 27 for cubic yards. Sloped wall trenches add volume at the top of the cut, increasing spoil significantly on deep excavations. Always apply a swell factor when calculating spoil — clay soils can swell 30% or more when excavated. For OSHA trench safety, Type A soil requires 3/4:1 (H:V) sloping minimum; Type C (the most conservative classification) requires 1.5:1. Use this excavation cubic yards calculator during takeoff to size your equipment, plan truck counts, and confirm disposal site capacity before breaking ground.
| Soil Type | OSHA Slope Ratio | Angle from Horizontal | Description |
|---|---|---|---|
| Type A (stable) | 3/4:1 (H:V) | 53° | Hard clay, stable rock — uncommon in practice |
| Type B (medium) | 1:1 (H:V) | 45° | Angular gravel, silt, fissured soil |
| Type C (unstable) | 1.5:1 (H:V) | 34° | Sandy, granular, submerged — most conservative |
| Rock (stable) | Vertical (90°) | 90° | Competent rock with no fracture planes |
OSHA 1926 Subpart P. Sloping requirements apply to excavations 5 ft deep and over. When in doubt, classify as Type C. A competent person must classify soil on-site.
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Start free trialFor a rectangular pit: Length × Width × Depth = cubic feet, then divide by 27 for cubic yards. For sloped walls (required by OSHA for trenches deeper than 5 ft in most soil types), account for the additional width at the top.
A standard tandem dump truck holds 12–16 cubic yards. A tri-axle holds 14–18 CY. Super dumps can hold up to 26 CY. Use 14 CY as a conservative estimate for planning.
When soil is excavated it expands in volume — typically 10–30% depending on soil type. Clay swells more than sand. Always add the swell factor when calculating spoils hauling.
OSHA requires protective systems (sloping, shoring, or trench boxes) for trenches 5 feet or deeper. Type A soil requires 3/4:1 (H:V) sloping minimum. Type C (most common) requires 1.5:1. Always consult OSHA 1926 Subpart P.