Stone Fill Calculator: Volume & Weight

This stone fill calculator works out how much crushed stone, gravel, or similar fill material you need for a project. You enter the length, width, and depth of the area to be filled, and it returns the volume in cubic yards and cubic meters, plus the estimated weight in tons and kilograms based on a typical density. The result helps you order the right amount of material and avoid paying for excess or running short mid-project.

Formula

The calculator uses the basic volume formula for a rectangular prism, then converts to common fill-material units.

Volume (cubic feet) = Length (ft) × Width (ft) × Depth (ft)

Since depth is entered in inches, it is first converted to feet by dividing by 12. The volume in cubic feet is then converted to cubic yards (divide by 27, because 1 cubic yard = 27 cubic feet) and to cubic meters (multiply by 0.0283168).

Weight is estimated by multiplying the volume in cubic feet by the material density in pounds per cubic foot, then converting to US tons (divide by 2000) or kilograms (multiply by 0.453592).

• L = length in feet
• W = width in feet
• D = depth in inches
• Density = material weight per cubic foot (lb/ft³)

Worked Example

Using the default values: length = 10 ft, width = 10 ft, depth = 4 in, density = 100 lb/ft³.

1. Convert depth to feet: 4 in ÷ 12 = 0.3333 ft
2. Volume in cubic feet: 10 × 10 × 0.3333 = 33.33 ft³
3. Volume in cubic yards: 33.33 ÷ 27 = 1.23 yd³ (rounded to 2 decimals)
4. Volume in cubic meters: 33.33 × 0.0283168 = 0.94 m³
5. Weight in US tons: (33.33 × 100) ÷ 2000 = 1.67 tons
6. Weight in kg: (33.33 × 100) × 0.453592 = 1512 kg (rounded to whole number)

The calculator shows 1.23 cubic yards, 0.94 cubic meters, 1.67 US tons, and 1512 kg for the defaults.

How to Use the Results

The volume number is what you order from a supplier. Most crushed stone and gravel is sold by the cubic yard (in the US) or cubic meter (in most other countries). The weight estimate is useful for transport planning – knowing the tonnage helps you decide whether a pickup truck or a delivery truck is needed, and whether your site can support the load.

For a simple rectangular area like a patio base, garden path, or French drain trench, this calculation is accurate. For irregular shapes, break the area into rectangles, calculate each separately, and add them together.

Choosing the Right Density

The density field is the most variable input. The default of 100 lb/ft³ is a reasonable average for many crushed stones, but actual values range from about 90 to 130 lb/ft³. Here are typical ranges:

• Sand: 90–110 lb/ft³
• Gravel (loose, dry): 95–115 lb/ft³
• Crushed limestone: 100–120 lb/ft³
• Crushed granite: 105–130 lb/ft³
• Recycled concrete: 100–120 lb/ft³

If you know the specific material’s density from the supplier, use that. If not, 100 is a safe middle estimate for most fill applications. The weight is an estimate, not a precise measurement – moisture content and compaction change the actual weight.

Common Mistakes and How to Avoid Them

• Mixing units: Entering length in feet but depth in inches without converting leads to errors. This calculator handles that conversion for you, but if you do it manually, always convert depth to feet first.
• Forgetting compaction: When you compact stone, it settles and takes up less volume. Order about 10–15% extra for compacted bases. For example, if the calculator says 1.23 yd³, order about 1.4 yd³.
• Depth measurement: Measure the actual depth of the void, not the depth of the bag or the intended depth after compaction. If you are filling a trench, measure from the bottom to the final surface level.
• Rounding too early: If you round the cubic feet to 33 before multiplying by density, you get a slightly different weight. Keep full precision until the end.

Limitations of the Formula

This calculator assumes a flat, rectangular area with uniform depth. Real-world projects often have slopes, curved edges, or varying thicknesses. For those, you need to measure at several points and average the depth, or break the area into smaller rectangles.

The weight estimate assumes a single uniform density across the entire volume. In practice, the material at the bottom may be more compacted than the top, especially if you are using a plate compactor. The density you enter should be the loose density of the material as delivered, not the compacted density.

Finally, this is a geometric and density calculation – it does not account for waste, spillage, or uneven settling. Adding 5–10% to the final order is standard practice for any fill project.

Frequently Asked Questions

How many cubic feet are in a cubic yard?

There are 27 cubic feet in one cubic yard (3 feet × 3 feet × 3 feet). This is why the volume in cubic feet is divided by 27 to get cubic yards.

How much stone do I need for a 10×10 area, 4 inches deep?

Using the calculator defaults: 10 ft × 10 ft × (4/12) ft = 33.33 cubic feet, which is 1.23 cubic yards. That’s about 1.67 tons at a density of 100 lb/ft³. For a compacted base, order about 1.4 cubic yards to allow for settling.

What is the difference between crushed stone and gravel?

Crushed stone is made by mechanically crushing larger rocks, so it has angular edges. Gravel is naturally rounded, often found in riverbeds. Both are used as fill, but crushed stone locks together better for paths and bases, while gravel drains more easily.

How do I convert cubic yards to tons?

Multiply the volume in cubic yards by the material density in pounds per cubic foot, then divide by 2000 (since there are 2000 lb in a US ton). For example, 1.23 yd³ × 100 lb/ft³ × 27 ft³/yd³ ÷ 2000 = 1.67 tons.

Should I order extra stone?

Yes, for most projects it is wise to order 5–10% extra to cover waste, spillage, and compaction. For a base that will be compacted, add 10–15% because the stone settles into a smaller volume.

Can this calculator handle circular areas?

No, this calculator is for rectangular areas only. For a circle, use the formula π × radius² × depth, then convert to cubic yards. You can do that separately and then use the density to estimate weight.

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in l | Length | ft | 10 | 0
in w | Width | ft | 10 | 0
in d | Depth | in | 4 | 0
in density | Material density | lb/ft³ | 100 | 0
out volume_cy | Volume | cubic yards | (l * w * (d / 12)) / 27 | 2
out volume_m3 | Volume | cubic meters | (l * w * (d / 12)) * 0.0283168 | 2
out weight_tons | Estimated weight | US tons | ((l * w * (d / 12)) * density) / 2000 | 2
out weight_kg | Estimated weight | kg | ((l * w * (d / 12)) * density) * 0.453592 | 0