How to Calculate Material Needs
Material Weight by Type
| Material | lb/ft³ | kg/m³ | Tons/cu yd |
|---|---|---|---|
| Crushed Stone | 100 | 1,600 | 1.35 |
| Pea Gravel | 95 | 1,520 | 1.28 |
| River Rock | 105 | 1,680 | 1.42 |
| Decomposed Granite | 90 | 1,442 | 1.22 |
| Road Base / Crusher Run | 130 | 2,082 | 1.76 |
| Lava Rock | 60 | 960 | 0.81 |
Pro Tip: Always Order Extra
Add 5–10% to your resulting total to account for compaction, settling, and spillage during installation. Suppliers often require minimum delivery amounts, so rounding up to the nearest half or full unit is wise. For driveway and road-base work, compacted thickness can be up to 25% less than loose fill — plan accordingly.
How This Tool Works
Select your project shape (rectangle, circle, triangle, or irregular), then enter the dimensions. The calculator computes area, multiplies by your chosen depth, and converts to volume. Each aggregate type has its own density profile — 100 lb/ft³ for crushed stone, 95 for pea gravel, 105 for river rock, 90 for decomposed granite, 130 for road base, and 60 for lava rock. Results update instantly with no page reload.
The output panel shows four key metrics: volume (switchable between cubic yards, cubic feet, or cubic meters), weight (US tons, pounds, metric tonnes, or kilograms), bag count (for 0.5, 0.75, or 1.0 cu ft bag sizes), and a cost estimator. Enter a price per unit and the total updates in real time. A system toggle lets you flip between imperial and metric units across all inputs and outputs at once.
Material densities are based on published engineering references and industry standards. Real-world values vary by region, moisture content, and supplier — always confirm with your local supplier and add a 5-10% surplus to your order for compaction and settling.
Frequently Asked Questions
How do I figure out what quantity I need?
Multiply length × width × depth (all in feet), then divide by 27 to get volume in cu yd. This tool handles all of that math instantly — just enter your dimensions above.
What volume for a 10×10 area at 3 inches deep?
A 10×10 ft space at 3 in (0.25 ft) deep holds 25 cu ft, which equals about 0.93 cu yd. That's roughly 1.16 US tons of crushed stone.
How do I convert volume into weight?
After getting your volume in cu yd, multiply by the material density. Crushed stone sits around 100 lb/ft³, so 1 cu yd weighs about 1.35 US tons. The converter here does the math for you.
What depth is recommended for each use case?
For decorative paths and gardens: 2–3 in. For driveways: 4 in. For playgrounds: 6 in (ASTM F1292 safety minimum). For French drains: 6–12 in.
What do different materials typically cost?
Crushed stone runs $15–$75 per US ton depending on type and delivery. Pea gravel is $25–$50/ton. Enter your local price in the cost estimator to get an instant project total.
How are cubic yards different from tons?
Cu yd measure volume; tons measure weight. The conversion factor depends on material density. Crushed stone: 1 cu yd ≈ 1.35 US tons. Pea gravel: 1 cu yd ≈ 1.28 US tons.
How many bags will I need?
Divide total cu ft by the bag size. Standard bags hold 0.5 cu ft. For a 10×10 space at 3 in deep (25 cu ft), you would need about 50 bags. This tool shows counts for 0.5, 0.75, and 1.0 cu ft bag sizes.