Field Guide
How Much Gravel Do I Need? The Complete US Contractor & DIY Guide
Whether you're ordering a tri-axle of crusher run for a new driveway or picking up a few bags of pea gravel for a garden path, the math is the same: measure the volume, account for compaction, and convert to weight using the right aggregate density.
1. How to Calculate Gravel Tonnage (The Math Explained)
Gravel is sold by volume (cubic yards) or by weight (short tons). Your measurements come in feet and inches, so you'll convert in four steps. Here's the exact process this calculator uses.
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1
Convert depth from inches to feet
Depth is usually specified in inches, but length and width are in feet. Divide inches by 12.
Depth (ft) = Depth (in) ÷ 12 Example: 4 in ÷ 12 = 0.333 ft -
2
Calculate area, then cubic feet
Find the surface area in square feet, then multiply by depth to get the raw (loose) volume. Rectangles use length × width; round areas such as fire pits and tree rings use the circle formula.
Rectangle: Area = Length (ft) × Width (ft) Circle: Area = π × Radius² (Radius = Diameter ÷ 2) Cubic Feet = Area (sq ft) × Depth (ft) Example (rectangle): 50 × 12 = 600 sq ft × 0.333 = 200 ft³ Example (12 ft circle): 3.1416 × 6² = 113.1 sq ft -
3
Add compaction & waste, then convert to cubic yards
Loose stone settles and compacts. Add a factor (typically 5–15%), then divide by 27 — there are 27 cubic feet in one cubic yard (3 ft × 3 ft × 3 ft).
Final Volume = Raw Volume × (1 + Compaction % ÷ 100) Cubic Yards = Final Cubic Feet ÷ 27 Example: 200 × 1.10 = 220 ft³ → 220 ÷ 27 = 8.15 yd³ -
4
Convert cubic yards to tons
Multiply cubic feet by the material's density in pounds per cubic foot, then divide by 2,000. US quarries sell by the short ton (2,000 lbs), not the metric tonne (2,204.6 lbs).
Pounds = Final Cubic Feet × Density (lbs/ft³) Tons = Pounds ÷ 2,000 (or Cubic Yards × tons/yd³) Example (Crusher Run @ 110 lbs/ft³): 220 × 110 = 24,200 lbs 24,200 ÷ 2,000 = 12.10 tons
Quick unit conversions
- 1 cubic yard = 27 cubic feet
- Density (lbs/ft³) = Density (tons/yd³) × 2,000 ÷ 27 ≈ tons/yd³ × 74.07
- Density (tons/yd³) = Density (lbs/ft³) × 27 ÷ 2,000 = lbs/ft³ × 0.0135
- Example: 110 lbs/ft³ × 0.0135 = 1.485 ≈ 1.49 tons/yd³ (about 1.5 tons per yard)
- One 50 lb retail bag ≈ 0.5 cubic feet of gravel
2. Gravel & Aggregate Density Reference Table
How much does a cubic yard of gravel weigh? It depends on the stone. These are average dry, loose densities for common US landscape and construction aggregates. Wet stone can weigh 5–10% more, and every quarry's rock is a little different, so confirm with your supplier's scale ticket data.
| Material | Typical Size | Lbs / ft³ | Tons / yd³ | Best Uses |
|---|---|---|---|---|
| Pea Gravel | 3/8" | ≈ 105 | 1.42 | Walkways, play areas, dog runs, fire pit surrounds |
| Crushed Stone | 3/4" | ≈ 100 | 1.35 | Driveway top coat, drainage, concrete aggregate |
| Decomposed Granite | 1/4" minus | ≈ 115 | 1.55 | Pathways, patios, xeriscape, deck footing pads |
| River Rock | 1"–3" | ≈ 98 | 1.32 | Dry creek beds, edging, downspout splash areas |
| Crushed Concrete Base | 1-1/2" minus | ≈ 95 | 1.28 | Recycled sub-base for driveways, pads & parking areas |
| Crushed Base / Crusher Run | 3/4" minus | ≈ 110 | 1.49 | Default calculator preset: driveway & paver sub-base |
| Sand & Gravel Mix | Blended | ≈ 120 | 1.62 | Fill, backfill, pipe bedding |
| #57 Crushed Stone | 3/4"–1" | ≈ 104 | 1.40 | French drains, drainage layers |
3. Recommended Gravel Depth Guide
How deep should gravel be? Ordering the wrong depth is the #1 cause of rutted driveways, sunken pavers, and drains that clog in a season. Use these field-tested ranges as your starting point, and go to the deeper end over clay, wet, or freeze-thaw-prone soils.
Standard installed depths by project
2–3 in
Walkways & Footpaths
Pea gravel or decomposed granite
Foot traffic only. Lay over landscape fabric with steel, paver, or timber edging so stone stays put.
3–4 in
Patio Bases & Fire Pits
Compacted crushed base; pea gravel for fire pit surrounds
Under pavers, compact crushed base in one lift and add 1 in of bedding sand. For round fire pit pads, switch the zone shape to Circle / Round.
4–6 in
Residential Driveways
Crusher run base + optional 2 in #57 top coat
Use 4 in on firm, well-drained soil for passenger cars; go to 6 in over clay, in freeze-thaw regions, or for trucks. Compact in 3 in lifts.
8–12 in
French Drains & Drainage
Clean #57 crushed stone
Wrap the trench in filter fabric and surround the perforated pipe with stone. Never use crusher run here; its fines clog the drain.
Heavy equipment & construction entrances: trucks, RVs, and job-site traffic need 6–12 in of base, installed in 3–4 in lifts with larger stone (#3 or #4) below and crusher run on top.
Compaction factors: crusher run vs. drainage stone
Loose material delivered by the truck occupies more volume than it will after it's compacted and settled. That's why every serious estimate includes a compaction and waste factor.
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Crusher run / dense grade: 10–15%. Fines lock together under a plate compactor and the material consolidates significantly. Use 15% on soft or freshly excavated subsoil.
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#57 stone & drainage aggregate: 5–8%. Clean, angular stone self-locks with minimal settling. The factor mainly covers spillage and uneven trench bottoms.
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Pea gravel & river rock: 5%. Rounded stone doesn't compact much, but it migrates. Budget a little extra for edges and future topdressing.
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Decomposed granite: 10–20%. Stabilized DG compacts heavily when wetted and rolled in lifts.
Pro tip from the field
Running short by half a ton means paying a second delivery fee — often $75–$150. Rounding your order up to the next half or whole ton is almost always cheaper than a return trip.
4. Frequently Asked Questions
How many tons of gravel are in a cubic yard?
Most gravel weighs about 1.3 to 1.6 short tons per cubic yard (95–120 lbs/ft³). This calculator's default crushed base / crusher run uses 110 lbs/ft³, which is 1.49 tons per cubic yard, so about 1.5 tons per yard is a reliable rule of thumb for budgeting.
Lighter materials include crushed concrete base (≈ 1.28 tons/yd³), river rock (≈ 1.32), and 3/4" crushed stone (≈ 1.35). Pea gravel runs ≈ 1.42, decomposed granite ≈ 1.55, and a sand & gravel mix ≈ 1.62 tons per cubic yard.
How many square feet does a ton of gravel cover?
At 110 lbs/ft³, one ton is about 18.2 cubic feet of stone. Spread at common depths, that covers roughly:
- 2 in deep: ~109 sq ft
- 3 in deep: ~73 sq ft
- 4 in deep: ~55 sq ft
- 6 in deep: ~36 sq ft
Lighter stone like river rock covers a little more per ton; heavier blends cover a little less.
How much gravel do I need for a 10×10 area?
A 10 ft × 10 ft area (100 sq ft) at 4 in deep is 33.3 cubic feet, or 1.23 cubic yards. At 110 lbs/ft³ that weighs about 1.83 tons, or roughly 2.0 tons after a 10% compaction allowance. At 2 in deep you would need about half that: 0.62 cubic yards, or 0.92 tons before compaction.
How do I calculate gravel for a circular area like a fire pit?
Use the circle formula: Area = π × radius², where the radius is half the diameter. A 12 ft round fire pit pad has a 6 ft radius, so its area is 3.1416 × 36 = 113.1 sq ft. At 3 in deep (0.25 ft) that is 28.3 cubic feet, or 1.05 cubic yards: about 1.48 tons of pea gravel at 105 lbs/ft³. In the calculator above, switch a zone to Circle / Round and enter either the diameter or the radius.
How much area does a 50 lb bag of pea gravel cover?
A standard 50 lb bag holds roughly 0.5 cubic feet. Coverage depends on depth:
- 1 in deep: ~6 sq ft per bag
- 2 in deep: ~3 sq ft per bag
- 3 in deep: ~2 sq ft per bag
For anything over about 1 cubic yard (54 bags), bulk delivery is usually far cheaper per ton than bagged stone.
What is the difference between #57 stone and Crusher Run?
#57 stone is clean, washed, angular stone sized about 3/4" to 1" with no fines. Water drains straight through it, making it ideal for French drains, behind retaining walls, and as a driveway top layer.
Crusher run (also called dense grade aggregate, DGA, #411, ABC, or road base) is crushed stone blended with stone dust. It compacts into a hard, nearly impervious base, which is perfect under pavers, patios, and driveways but poor for drainage.
A common driveway build uses 4–6 in of compacted crusher run topped with 2 in of #57 stone.
How many cubic yards fit in a pickup truck or dump truck?
Weight, not bed size, is the limit. A half-ton pickup should carry no more than about 1 ton (~0.7 yd³) of gravel; a 3/4-ton about 1.5 tons. A tri-axle dump truck typically hauls 15–22 tons depending on state weight limits. This calculator uses a conservative 15 tons per load.