Sand Calculator Cubic Feet: How Much Sand Do I Need?

This sand calculator converts your project’s length, width, and depth into the volume of sand needed in both cubic feet and cubic yards. Enter the area dimensions and desired sand depth, and the tool instantly tells you how much sand to order for a sandbox, paver base, or fill project.

Formula

The calculator uses the basic volume formula for a rectangular prism:

Volume (ft³) = Length (ft) × Width (ft) × Depth (in) ÷ 12

Since depth is entered in inches, dividing by 12 converts it to feet. The cubic yard result is then found by dividing the cubic feet by 27 (because 1 yard = 3 feet, so 1 yd³ = 3 × 3 × 3 = 27 ft³). The calculator combines these steps into one expression: l * w * d / 324 (which is 12 × 27).

• l = length of the area, in feet
• w = width of the area, in feet
• d = depth of sand, in inches
• Volume (ft³) = cubic feet of sand required
• Volume (yd³) = cubic yards of sand required (useful for bulk orders)

Worked Example

Using the default values from the calculator: length = 40 ft, width = 25 ft, depth = 3 in.

1. Convert depth to feet: 3 in ÷ 12 = 0.25 ft
2. Calculate area: 40 ft × 25 ft = 1000 ft²
3. Multiply by depth: 1000 ft² × 0.25 ft = 250 ft³
4. Convert to cubic yards: 250 ft³ ÷ 27 = 9.26 yd³

The calculator rounds to 9.26 yd³ and 250.0 ft³, matching the example exactly.

Why Cubic Feet Matter for Sand

Sand is sold by volume, not weight, so knowing the cubic footage is essential. A cubic foot of dry sand weighs roughly 100 pounds (45 kg), but that varies with moisture content. When you order from a bulk supplier, they typically quote in cubic yards; bagged sand (like play sand or paver sand) is sold in cubic feet (often 0.5 or 1 ft³ per bag). Understanding both units lets you compare prices and avoid over- or under-ordering.

How to Measure Your Project Area

For a simple rectangle, measure the length and width in feet. For irregular shapes, break the area into rectangles, calculate each, and add them together. If you have a circular sandbox, use the formula π × r² × depth (with r = radius in feet). For a triangular area, use 0.5 × base × height × depth. Always measure in the same unit; if you measured in inches, convert to feet first (divide by 12).

Choosing the Right Depth

The depth you need depends on the project:

• Sandbox: 4–6 inches of play sand is typical for safe digging.
• Paver base: 1 inch of sand under pavers is common, but some professionals recommend up to 2 inches for leveling.
• Under a pool or trampoline: 2–3 inches of sand provides a cushion and level surface.
• Fill dirt replacement: Depth varies widely; measure the void to be filled.

If you’re unsure, consult a landscape supplier or contractor—they can advise based on local soil and project type.

Common Mistakes and How to Avoid Them

The most frequent error is mixing units. For example, entering depth in feet instead of inches will give an answer 12 times too large. Another mistake is forgetting to convert cubic feet to cubic yards when ordering bulk sand—suppliers often charge per yard, and a yard covers 27 cubic feet. Also, sand compacts when spread; order about 10% extra to account for settling and waste, especially for paver bases.

Bulk vs. Bagged Sand: What to Know

Bulk sand is delivered by the cubic yard and is cheaper per volume, but you need a place to dump it and a wheelbarrow to move it. Bagged sand is easier to handle and store, but you’ll pay a premium. To convert cubic feet to bags, divide the total cubic feet by the bag size (e.g., 0.5 ft³ per bag). For the default example of 250 ft³, you’d need 500 half-cubic-foot bags—that’s a lot, so bulk delivery is usually smarter for large areas.

Frequently Asked Questions

How many cubic feet are in a ton of sand?

A ton of dry sand is about 20 cubic feet, but this varies with moisture and grain size. Wet sand is heavier, so a ton may be less than 20 ft³. Always check with your supplier for the specific weight per cubic foot of the sand they sell.

How do I calculate sand for a circular sandbox?

Measure the radius (half the diameter) in feet, then use the formula: 3.14 × radius × radius × depth (in feet). For example, a 6-foot diameter sandbox with 4 inches (0.33 ft) of sand needs 3.14 × 3 × 3 × 0.33 ≈ 9.3 ft³.

Should I order extra sand?

Yes, add 5–10% to your calculated volume to account for compaction, spillage, and uneven ground. For a sandbox, extra sand is useful for topping up later. For paver bases, a little extra ensures you can level properly.

What’s the difference between play sand and paver sand?

Play sand is washed, fine, and safe for children; paver sand is coarser and often contains stabilizers to prevent shifting. Both are measured in cubic feet, but they are not interchangeable. Use the calculator for volume, then choose the right type for your project.

Can I use this calculator for gravel or soil?

Yes, the volume calculation is identical for any granular material. However, weight per cubic foot differs—gravel is heavier than sand, and soil varies. For weight estimates, multiply the cubic feet by the material’s density (e.g., gravel ≈ 110 lb/ft³, topsoil ≈ 75 lb/ft³).

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in l | Lawn length | ft | 40 | 0 | 100000
in w | Lawn width | ft | 25 | 0 | 100000
in d | Depth | in | 3 | 0 | 120
out yd | Volume | yd³ | l * w * d / 324 | 2
out ft3 | Volume | ft³ | l * w * d / 12 | 1