Impact Tech Solutions · HSE Calculators
EXCAVATION SLOPE
Excavation Slope & Shoring Calculator
Calculates the maximum allowable sloping angle, required horizontal offset, and top excavation width, per OSHA 29 CFR 1926 Subpart P, Appendix B (Sloping and Benching).
Critical safety context: Soil must be classified by a competent person per OSHA Appendix A before this table can be applied — the classification (Stable Rock, Type A, B, or C) depends on cohesion, moisture, prior disturbance, fissures, groundwater, vibration exposure, and other site-specific factors that only a qualified, trained person can assess in the field. This calculator only performs the arithmetic once that classification is known. Excavations 5 feet or deeper require a protective system (sloping, shoring, or shielding) unless entirely in stable rock. Excavations deeper than 20 feet require sloping/benching designed by a registered professional engineer — this tool's simplified tables do not apply beyond 20 feet.
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Max. Allowable Slope
0 ft
Horizontal Offset (each side)
0 ft
Top Width of Excavation
Formula Reference
Horizontal Offset (per side) = Depth × Slope Ratio (H:V)Top Width = Bottom Width + (2 × Horizontal Offset)
Minimum spoil pile / equipment setback from excavation edge = 2 feet (OSHA 1926.651(j)(2))
OSHA Maximum Allowable Slopes (Appendix B, Table B-1)
| Stable Rock | Vertical — 90° |
| Type A | 3/4H:1V — 53° |
| Type A (short-term, ≤ 12 ft depth) | 1/2H:1V — 63° |
| Type B | 1H:1V — 45° |
| Type C | 1½H:1V — 34° |
Methodology, interpretation & sources
Purpose. Calculates the maximum allowable sloping angle, required horizontal offset, and top excavation width, per OSHA 29 CFR 1926 Subpart P, Appendix B (Sloping and Benching).
Primary references. Use the current edition/version that applies to your jurisdiction and organization:
Editorial note. Prepared and maintained by Impact Tech Solutions. Editorially updated 28 September 2026. No individual professional credential is claimed on this page; high-consequence, statutory, tax, engineering or health decisions should be independently verified against the current primary source and, where required, a qualified professional.