Gravel Calculator: Sq Ft & Cubic Yards

A gravel calculator for square feet tells you how much gravel you need to cover a given area. You enter the length and width of the space in feet (or inches), the desired gravel depth in inches, and the calculator returns the volume in cubic feet and cubic yards, plus the approximate weight in tons. This lets you order the right amount of material for a driveway, walkway, or garden bed without overbuying or running short.

Formula

The core formula is simple: multiply length by width to get the area in square feet, then multiply by the depth (converted to feet) to get the volume in cubic feet. Then divide by 27 to convert to cubic yards, since one cubic yard equals 27 cubic feet.

In symbols: V_ft³ = L × W × D, where L is length in feet, W is width in feet, and D is depth in feet (inches divided by 12). Then V_yd³ = V_ft³ / 27.

For weight, the calculator multiplies the cubic yards by 1.4 tons per cubic yard. This is a common average for gravel; actual density ranges from about 1.2 to 1.7 tons per cubic yard depending on the stone type and moisture content.

Worked Example

Using the default values from the calculator: length = 20 ft, width = 10 ft, depth = 3 in.

1. Convert depth to feet: 3 in ÷ 12 = 0.25 ft.
2. Calculate area: 20 ft × 10 ft = 200 sq ft.
3. Calculate volume: 200 sq ft × 0.25 ft = 50 cu ft.
4. Convert to cubic yards: 50 cu ft ÷ 27 = 1.85 cu yd.
5. Estimate weight: 1.85 cu yd × 1.4 tons/cu yd = 2.59 tons.

The calculator rounds the volume to 1.85 cubic yards and the weight to 2.59 tons. If you order from a supplier, you would likely order 2 cubic yards and accept the small surplus, or round up to 3 if you want extra for compaction.

How to Measure Your Area

Accurate measurements are the difference between a good estimate and a wasted trip to the quarry. Use a tape measure or a laser distance measurer, and follow these steps:

• For a rectangle, measure the longest length and widest width in feet. If your space is irregular, divide it into rectangles, calculate each, and add them together.
• For a circular bed, measure the diameter (distance across the center) in feet, then use the formula area = Ï€ × (diameter/2)².
• For a triangular area, measure the base and height in feet, then multiply base × height × 0.5.
• Always measure in the same unit. If you have inches, convert to feet by dividing by 12 before entering.

If you are covering an existing surface with loose gravel, measure the depth of the old layer to decide whether you need to add more or replace it entirely.

Choosing the Right Depth

The depth you need depends on what the gravel is for. Too shallow and the gravel shifts or exposes the ground; too deep and you waste money and make walking difficult.

• Walkways and paths: 2–3 inches is typical for a stable surface.
• Driveways: 4–6 inches for passenger vehicles, often layered with a base of larger stone.
• Under pavers or as a base: 4–6 inches of compacted gravel, depending on the soil.
• Decorative garden beds: 2–3 inches is enough to suppress weeds while still showing the stone.

If you are unsure, check with a local landscaping supplier—they know the typical depth for your area and soil type. For a driveway, consider that a single layer of gravel will sink into soft soil; a geotextile fabric underneath can prevent that.

Common Mistakes and How to Avoid Them

The most frequent errors are unit mix-ups and ignoring compaction. Here are the pitfalls to watch for:

• Mixing feet and inches: Depth is usually given in inches, but length and width in feet. Always convert depth to feet (divide by 12) before multiplying.
• Forgetting to divide by 27: Cubic yards are the standard unit for gravel orders, but many people calculate cubic feet and then order the wrong amount.
• Ignoring compaction: Freshly spread gravel settles and compacts by about 10–20%. If your project needs a precise final depth, order 10–15% extra to account for settling.
• Assuming all gravel weighs the same: Pea gravel is lighter than crushed stone of the same volume. The 1.4 tons per cubic yard is an average; check the specific gravity of the stone you plan to buy.
• Rounding too early: Round only at the end. If you round 1.85 cubic yards down to 1.5, you will be short.

If you are ordering by the ton, use the weight estimate from the calculator, but confirm with the supplier—they often quote by the ton and can tell you the exact weight of their gravel per cubic yard.

What the Result Means When You Order

Gravel is sold by the cubic yard (for bulk deliveries) or by the 50-pound bag (for small projects). A cubic yard is a volume measure: 3 feet long × 3 feet wide × 3 feet deep. One cubic yard of gravel weighs roughly 2,800 pounds (1.4 tons), so a standard pickup truck can typically carry about 1–1.5 cubic yards depending on its payload capacity.

For a small project, a 50-pound bag covers about 3–4 square feet at a 3-inch depth. That means a 200 sq ft path at 3 inches deep would need roughly 50–67 bags—far more expensive than ordering a bulk delivery. For anything over about 20 square feet, bulk delivery is usually cheaper and more practical.

When you call a supplier, give them the cubic yards (not the square feet) and ask if they deliver by the yard or by the ton. If they quote by the ton, multiply your cubic yards by the density they specify (often 1.4–1.5 tons per yard).

Alternatives to Traditional Gravel

Gravel is not the only option for paths and driveways. Depending on your goal, one of these might suit better:

• Decomposed granite (DG): Finer and more compactable than gravel; gives a smoother, more stable surface for walkways, but needs a binder to prevent dust.
• Crushed stone #57: A common choice for driveways because it interlocks well; the calculator works the same for any angular stone.
• Pea gravel: Rounded and easier on bare feet, but it shifts more and is not ideal for driveways.
• Rubber mulch or wood chips: Lighter and softer, but they decompose or need replacement more often than stone.
• Pavers or concrete: More expensive and permanent, but no ongoing maintenance or displacement.

If you are comparing costs, remember that gravel is cheap per cubic yard but may need replenishing every few years. Pavers cost more upfront but last decades with minimal care.

Frequently Asked Questions

How many square feet does a cubic yard of gravel cover? At a 3-inch depth, one cubic yard (27 cu ft) covers 108 square feet (27 ÷ 0.25). At 4 inches, it covers 81 square feet; at 2 inches, 162 square feet. The formula is: square feet = 27 / (depth in feet).

How do I convert square feet to cubic yards for gravel? Multiply the square footage by the depth in feet to get cubic feet, then divide by 27. Example: 200 sq ft × 0.25 ft = 50 cu ft ÷ 27 = 1.85 cu yd.

How much gravel do I need for a 10×10 area? For a 10×10 ft area (100 sq ft) at 3 inches deep, you need 100 × 0.25 = 25 cu ft, which is 0.93 cubic yards. At 2 inches, it is 0.62 cubic yards. Use the calculator with your specific depth.

Should I order by the ton or by the cubic yard? It depends on how your supplier quotes. Most bulk suppliers sell by the cubic yard, but some quote by the ton. If by the ton, multiply your cubic yards by 1.4 (average) or ask for their exact density. Ordering by the ton is more accurate for weight-limited vehicles.

Does the calculator account for compaction? No, it gives the theoretical volume of loose gravel. When gravel is spread and compacted (especially in driveways), it settles by about 10–15%. To end up at your desired final depth, order 10–15% extra.

Can I use this calculator for pea gravel or crushed stone? Yes, the volume calculation is the same for any granular material. The only difference is the weight estimate—pea gravel is lighter (about 1.2 tons per cu yd) and crushed stone is heavier (up to 1.5 tons per cu yd). Adjust the tons per cubic yard in the formula if you know the exact density.

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in length | Length | ft | 20 | 0
in width | Width | ft | 10 | 0
in depth | Depth | in | 3 | 0
out cubic_ft | Volume | cu ft | length * width * depth / 12 | 2
out cubic_yd | Volume | cu yd | (length * width * depth / 12) / 27 | 2
out tons | Estimated weight | tons | ((length * width * depth / 12) / 27) * 1.4 | 2