Driveways, Bases & Pads · Contractor Estimation Tool

Shed Foundation Gravel Pad Calculator

Calculate washed #57 crushed stone or crusher run needed for a level, free-draining storage shed foundation pad with perimeter overhang.

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How the Shed Foundation Gravel Pad Calculator Works

Washed angular stone (such as ASTM #57, 3/4" clean stone) with minimal fines for high load-bearing capacity and free water drainage. Our Shed Foundation Gravel Pad Calculator computes exact geometric volume in cubic feet and cubic yards, then converts volume into US short tons (2,000 lbs) using the typical bulk density of Crushed Stone (#57 Clean Angular Stone) (2,700 lb/yd³ or 1.35 tons/yd³).

Mathematical Formula for Shed Gravel Pad:
1. Area (sq ft) = Length (ft) × Width (ft)
2. Volume (cu ft) = Area (sq ft) × [Depth (inches) ÷ 12]
3. Volume (cu yd) = Volume (cu ft) ÷ 27
4. Recommended Volume = Base Volume × (1 + 10% Ordering Adjustment)
5. Estimated Tons = Recommended Cubic Yards × 1.35 tons/yd³

Step-by-Step Worked Example

Example Project: 14 ft × 12 ft Area at 4 Inches Depth (+10% Adjustment)

Surface Area: 14 ft × 12 ft = 168 sq ft.
Base Volume: 168 sq ft × (4 ÷ 12) = 56.0 cu ft (2.07 cubic yards).
With +10% Ordering Adjustment: 2.07 yd³ × 1.10 = 2.28 cubic yards.
Weight in US Short Tons: 2.28 yd³ × 1.35 tons/yd³ = 3.08 tons (6,160 lbs).

Primary Applications & Contractor Best Practices

Concrete slab and shed sub-bases: Engineered for reliable coverage, drainage stability, and long-term performance.
Retaining wall backfill and drainage zones: Engineered for reliable coverage, drainage stability, and long-term performance.
Driveway intermediate layer (over coarse base): Engineered for reliable coverage, drainage stability, and long-term performance.
French drains and dry wells: Engineered for reliable coverage, drainage stability, and long-term performance.

Coverage & Tonnage Quick Reference Table (Crushed Stone (#57 Clean Angular Stone))

Estimated cubic yards and US short tons (including +10% ordering adjustment) across common project square footages:

Project Area	2" Depth	3" Depth	4" Depth	6" Depth
100 sq ft	0.92 t (0.68 yd³)	1.38 t (1.02 yd³)	1.83 t (1.36 yd³)	2.75 t (2.04 yd³)
250 sq ft	2.29 t (1.70 yd³)	3.44 t (2.55 yd³)	4.58 t (3.40 yd³)	6.88 t (5.09 yd³)
500 sq ft	4.58 t (3.40 yd³)	6.88 t (5.09 yd³)	9.17 t (6.79 yd³)	13.75 t (10.19 yd³)
1,000 sq ft	9.17 t (6.79 yd³)	13.75 t (10.19 yd³)	18.33 t (13.58 yd³)	27.50 t (20.37 yd³)
1,500 sq ft	13.75 t (10.19 yd³)	20.63 t (15.28 yd³)	27.50 t (20.37 yd³)	41.25 t (30.56 yd³)

Frequently Asked Questions

Multiply your project length (14 ft) by width (12 ft) to get area (168 sq ft). Multiply by depth in feet (4 in ÷ 12 = 0.33 ft) to get 56.0 cubic feet, then divide by 27 to get 2.07 base cubic yards. Adding a 10% ordering adjustment gives 2.28 yd³, which equals 3.08 US short tons at 2700 lb/yd³.

One cubic yard (27 cubic feet) of Crushed Stone (#57 Clean Angular Stone) weighs approximately 2,700 pounds, or 1.35 US short tons (100 lbs per cubic foot). Typical regional quarry densities range between 2,550 and 2,850 lb/yd³.

For most shed gravel pad installations, a typical compacted depth is 4 inches (our default preset uses 4 inches). Always excavate soft organic topsoil and install woven or non-woven geotextile fabric before spreading aggregate.

At 1.35 tons per cubic yard, 1 US short ton equals 0.74 cubic yards (20.0 cu ft). That covers approximately 120 sq ft at 2" deep, 80 sq ft at 3" deep, and 60 sq ft at 4" deep.