Crushed Gravel Calculator: How Much You Need

A crushed gravel calculator works out the volume and weight of crushed stone you need for a project based on the area’s length, width, and desired depth. You enter those three measurements (in feet or meters), and the calculator returns the volume in cubic feet, cubic yards, or cubic meters, plus an estimated weight in tons. This lets you order the right amount of material without overbuying or running short.

Formula

The basic formula for crushed gravel volume is:

Volume = Length × Width × Depth

Where:

• Length – the longest side of the area, in feet (or meters)
• Width – the shorter side, in the same unit as length
• Depth – how thick the gravel layer will be, converted to the same unit (inches divided by 12 to get feet)

The result is a cubic measurement. To convert to cubic yards, divide by 27 (since 1 cubic yard = 27 cubic feet). To estimate weight, multiply the volume by the density of crushed stone (typically 100–135 lb/ft³) and divide by 2,000 to get tons.

Worked Example

Using the calculator defaults: a 20 ft × 10 ft area with a 4-inch depth and a density of 105 lb/ft³.

1. Convert depth to feet: 4 in ÷ 12 = 0.333 ft
2. Volume = 20 × 10 × 0.333 = 66.6 ft³
3. Cubic yards = 66.6 ÷ 27 = 2.47 yd³
4. Weight = 66.6 ft³ × 105 lb/ft³ = 6,993 lb
5. Tons = 6,993 ÷ 2,000 = 3.50 tons

So for that area, you’d need about 2.5 cubic yards or 3.5 tons of crushed gravel.

How to Use a Crushed Gravel Calculator

Using the calculator is straightforward, but you need accurate measurements. Here’s the process:

• Measure the length and width of the area in feet. For irregular shapes, break the area into rectangles and calculate each separately, then add them together.
• Decide on the depth. A typical depth for a gravel path is 2–3 inches; for a driveway, 4–6 inches (often with a larger base layer).
• Enter the numbers into the calculator. If you know the density of the specific gravel you’re using, adjust that field; otherwise, 105 lb/ft³ is a reasonable average for crushed stone.
• Read the volume in cubic yards (the unit most suppliers use) and the weight in tons (what you’ll order).

If you’re ordering by the cubic yard, round up to the next whole number to account for compaction and spillage. For weight, add 5–10% as a safety margin.

Choosing the Right Depth and Gravel Type

The depth you need depends on the project:

• Walkways and paths: 2–3 inches of gravel is usually enough.
• Driveways: 4–6 inches, often in two layers (4 inches of larger stone, then 2 inches of finer gravel on top).
• Base for pavers or sheds: 4–6 inches of compacted crushed stone.
• Drainage trenches: 6–12 inches, depending on water flow.

Also, crushed gravel comes in different sizes (e.g., #57 stone, #3 stone, stone dust). Larger stones have more air gaps, so they may require a slightly higher volume to fill the same area. The density field in the calculator can be adjusted: loose gravel might be around 95 lb/ft³, while compacted gravel can reach 125 lb/ft³.

Common Mistakes and How to Avoid Them

People often make these errors when calculating gravel needs:

• Mixing units: If you measure length in feet and depth in inches, you must convert depth to feet. Forgetting this leads to a volume 12 times too large.
• Forgetting to convert cubic feet to cubic yards: Suppliers sell by the cubic yard, not the cubic foot. Divide by 27.
• Ignoring compaction: Gravel settles and compacts, so the final depth will be less than the loose depth. Order 5–10% extra to compensate.
• Assuming all gravel weighs the same: Density varies by stone type and moisture. Check with your supplier if you need a precise weight.

Limits of the Formula

The calculator gives an estimate, not an exact order. The formula assumes a perfectly rectangular area and a uniform depth, which is rarely true in practice. Slopes, curves, and irregular edges all affect the real volume. Also, the density of crushed gravel is not a fixed number – it depends on the specific rock (limestone, granite, trap rock) and how it’s packed. The weight estimate is good for planning, but always confirm with your supplier, especially for large projects.

Frequently Asked Questions

How many cubic yards are in a ton of crushed gravel?

It depends on the density. For a typical crushed stone density of 105 lb/ft³, 1 ton (2,000 lb) equals about 19 ft³, or roughly 0.70 cubic yards. For lighter gravel (95 lb/ft³), a ton is about 0.78 cubic yards; for heavier (125 lb/ft³), it’s about 0.59 cubic yards.

What depth should I use for a gravel driveway?

For a residential driveway, a total of 4–6 inches is typical. Many builders use 4 inches of larger crushed stone (like #3) as a base, then add 2 inches of finer gravel (like #57) on top. For heavy vehicles, go to 6 inches total.

Should I order by weight or by volume?

Most suppliers sell crushed gravel by the cubic yard, but some quote by the ton. If you know the density, you can convert between them. If not, ask the supplier for their material’s density – it varies from around 95 to 125 lb/ft³.

How much extra should I order?

Add 5–10% to your calculated volume to account for compaction, spillage, and uneven ground. For a driveway that will be compacted, 10% is safer. For a small path, 5% is usually enough.

Can I use the calculator for pea gravel or other loose stone?

Yes, but adjust the density. Pea gravel is often around 95–100 lb/ft³, while crushed stone with fines might be 120–130 lb/ft³. The volume calculation stays the same; only the weight estimate changes.

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in length | Length | ft | 20 | 0
in width | Width | ft | 10 | 0
in depth | Depth | in | 4 | 0
in density | Density | lb/ft³ | 105 | 0
out volume_cu_ft | Volume | ft³ | length * width * (depth / 12) | 1
out volume_cu_yd | Volume | yd³ | (length * width * (depth / 12)) / 27 | 2
out weight_tons | Estimated weight | tons | (length * width * (depth / 12) * density) / 2000 | 2