Gravel Calculator
Calculate how many tons or cubic yards of gravel you need for any driveway, path, or landscaping project.
Planning a new driveway or landscaping upgrade? Instantly figure out the precise amount of crushed stone or pea gravel required for your coverage area to avoid over-ordering or falling short during construction.
Run a gravel calculator for a driveway and the math is straightforward volume and weight. Run the numbers for an aquarium instead, and the whole approach changes — gravel for a fish tank is sized by footprint and depth, not by gallons, which trips up more people than almost any other part of this topic.
The core gravel volume formula
Cubic yards = (Length × Width × Depth in feet) ÷ 27, then multiply by the material’s density to get weight. Depth in inches has to convert to feet first — 4 inches becomes 0.333 ft — before it goes into the formula.
Worked example: a 12 ft × 24 ft gravel path at 4 inches deep. 288 sq ft × 0.333 = 96 cubic feet, or 96 ÷ 27 = 3.56 cubic yards. At a typical crushed stone density of 1.4–1.5 tons per cubic yard, that’s roughly 5–5.3 tons before adding anything for compaction.
Why a pea gravel calculator can’t reuse the same density
Density swings more across gravel types than most people expect, which means tonnage for the same volume changes depending on what’s actually being ordered:
| Material | Density (per cubic yard) |
|---|---|
| Pea gravel | 2,500–2,700 lb (1.25–1.35 tons) |
| Standard crushed stone | 2,800–3,000 lb (1.4–1.5 tons) |
| Crushed limestone | 2,800–3,200 lb (1.4–1.6 tons) |
Pea gravel patio example: 10 ft × 12 ft at 2 inches deep. 120 sq ft × 0.167 = 20 cubic feet = 0.74 cubic yards. At 1.35 tons per cubic yard, that’s about 1.0 ton — noticeably less than the same volume in crushed stone would weigh.
Sizing gravel for a gravel driveway
A driveway isn’t one layer — it’s a stack of three, each doing a different job: a 4-inch base of larger #3 crushed stone for structure, a 3-inch middle layer of #57 stone for drainage, and a 2-inch top layer of #8 stone or pea gravel for the finished surface. Total depth across all three runs 6–9 inches.
Calculate each layer separately rather than averaging them into one blended depth — the base stone and the decorative top layer have different densities and different per-ton prices, so combining them into a single number tends to under- or over-order one layer to compensate for the other.
Cubic yards or tons: what a gravel calculator gives you either way
Landscaping suppliers quote small residential orders by the cubic yard; quarries and bulk deliveries quote by the ton. The conversion only needs the material’s density: multiply cubic yards by density per cubic yard, then divide by 2,000 for tons. For standard gravel at roughly 2,835 lb per cubic yard, that works out to about 1.42 tons per cubic yard as a quick mental shortcut.
Add 10–15% to whatever volume the raw formula gives you before ordering. Compaction settles loose gravel below the depth it was poured at, and irregular excavation edges almost never come out to a perfectly clean rectangle.
Fish tank gravel doesn’t scale with gallons the way people assume
The common shortcut — “one pound of gravel per gallon” — breaks down the moment two tanks hold the same water volume but different shapes. A 20-gallon long tank (30″ × 12″ footprint) and a 20-gallon tall tank (24″ × 12″ footprint) hold identical water, but the long tank’s bottom is 25% larger, so it needs noticeably more gravel to reach the same depth.
The footprint, not the gallon count, is what actually determines how much substrate covers the bottom at a given depth. A more reliable formula: Pounds of gravel ≈ (Tank length × width in inches ÷ 15) × Desired depth in inches.
Applied to both 20-gallon shapes at a 2-inch depth: the long tank needs (360 ÷ 15) × 2 ≈ 48 lb, while the tall tank needs (288 ÷ 15) × 2 ≈ 38 lb — a real 10-pound difference between two tanks sold under the identical “20-gallon” label. Fish-only setups generally call for 1–2 inches of depth; planted tanks do better with 2–3 inches to give root systems somewhere to anchor.
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For a standard gravel driveway, plan for a 4 to 6-inch base layer of compacted crushed stone plus a 2 to 3-inch top layer. A 12×50 foot driveway at 4 inches deep requires approximately 7.4 cubic yards or about 10 tons of material, depending on gravel type. Always add 10–15% to your calculated volume to account for compaction and settling.
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It depends on the gravel type. Pea gravel weighs approximately 1.3 tons per cubic yard, crushed stone about 1.35 tons, and dense-graded aggregate (crusher run) around 1.48 tons per cubic yard. Lava rock is much lighter at about 0.68 tons per cubic yard. Always confirm the density with your specific supplier, as it varies by source and moisture content.
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A new gravel driveway should have a total depth of 6 to 9 inches — typically a 4 to 6-inch compacted base layer of dense-graded aggregate and a 2 to 3-inch surface layer of crushed stone or pea gravel. Using only a surface layer without a compacted base leads to ruts, soft spots, and rapid deterioration under vehicle traffic.
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At 2 inches deep, 1,000 square feet requires approximately 6.2 cubic yards. At 3 inches, it's about 9.3 cubic yards. At 4 inches, approximately 12.3 cubic yards. Divide your square footage by 324 for a 1-inch depth in cubic yards, then multiply by the number of inches you need — this is the fastest manual shortcut for any coverage estimate.