Pea Gravel Yardage Calculator: How Much You Need

This pea gravel calculator works out the volume of gravel you need in cubic yards and cubic feet. You enter the length and width of the area in feet, plus the depth in inches, and it returns the exact amount to order. It uses the standard formula for a rectangular bed: length × width × depth, converted to cubic yards.

Formula

The calculator uses the volume formula for a rectangular prism: V = L × W × D, where:

• L = length of the area in feet (ft)
• W = width of the area in feet (ft)
• D = depth of the gravel layer in inches (in)
• V = volume in cubic yards (yd³)

Because there are 12 inches in a foot and 27 cubic feet in a cubic yard, the conversion factor is 12 × 27 = 324. So the full formula is:

V (yd³) = (L × W × D) / 324

If you prefer to work in metric, the same formula works with meters and centimeters: V (m³) = L (m) × W (m) × D (cm) / 100. One cubic yard equals approximately 0.7646 cubic meters.

Worked Example

Using the default values from the calculator above – a 40 ft long, 25 ft wide area at 3 inches deep – the calculation goes like this:

1. Multiply length by width: 40 ft × 25 ft = 1,000 ft² (square feet).
2. Multiply by depth in inches: 1,000 ft² × 3 in = 3,000 ft²·in.
3. Divide by 324: 3,000 / 324 = 9.26 yd³.

The calculator shows 9.26 cubic yards (rounded to two decimals), which matches exactly. In cubic feet, that is 3,000 / 12 = 250 ft³. So for a typical small patio or walkway of this size, you would order about 9.5 cubic yards of pea gravel.

Why Depth Matters More Than You Think

Pea gravel is sold by volume, not by weight, so the depth you choose dramatically changes the amount you need. A 2-inch layer is common for a decorative top dressing on existing soil or mulch. A 3-inch layer is standard for a walkway or play area where you want a stable surface. For areas that will support foot traffic or a patio base, 4 inches or more is often recommended.

Going from 2 to 4 inches doubles the volume. For a 10×10 ft area, that is the difference between 0.62 yd³ and 1.23 yd³. This is why the calculator asks for depth in inches – it is the most variable and most commonly miscalculated input. Many people measure the area carefully but then guess the depth, which can lead to ordering 50% too little or too much.

How to Measure Your Space Accurately

For a simple rectangle, measure length and width in feet using a tape measure. For irregular shapes, break the area into smaller rectangles or triangles, calculate each one separately, then add the volumes together. For a circular bed, use the formula π × r² (where r is the radius in feet) to get the area, then multiply by depth and divide by 324.

When measuring, always use the same unit – feet for length and width, inches for depth. A common mistake is mixing feet and inches. For example, a 10 ft by 10 ft area at 3 inches deep is 10 × 10 × 3 / 324 = 0.93 yd³. If you mistakenly enter 3 ft as the depth, the calculator would give 10 × 10 × 3 / 324 = 0.93 yd³ – but that would actually be 36 inches deep, a 12-fold error. Always convert inches to feet by dividing by 12, or keep the calculator’s units straight.

Ordering and Delivery Considerations

Pea gravel is typically sold in bulk by the cubic yard, or in 0.5-cubic-foot bags at home improvement stores. A cubic yard of pea gravel weighs roughly 2,800 to 3,000 pounds, depending on moisture and stone size. That is about 1.4 tons. For a 10×10 ft area at 3 inches deep (0.93 yd³), you would need about 1.3 tons.

If you order by the bag, divide the total cubic yards by 0.0185 (since a 0.5 ft³ bag is 1/54 of a cubic yard). For 0.93 yd³, that is about 50 bags. Bags are practical for small projects, but for anything over 1 cubic yard, bulk delivery is usually cheaper and involves far less lifting. Delivery trucks often spread the gravel in a pile, so plan for a wheelbarrow and shovel to move it into place.

Always order a small surplus – about 5–10% – to account for settling, spillage, and uneven ground. The calculator gives the exact volume for a flat, even layer, but real surfaces are rarely perfectly level. If you are filling a depression or a slope, you will need more.

Common Mistakes and How to Avoid Them

• Mixing units: Always use feet for length/width and inches for depth. The calculator’s formula assumes this.
• Forgetting to convert depth: 3 inches is 0.25 feet, not 3 feet. The calculator handles this, but if you do it by hand, divide inches by 12 first.
• Ignoring compaction: Pea gravel does not compact much, but it does settle slightly. Add 5–10% extra.
• Measuring the wrong area: For a path, measure the actual walking surface, not the entire yard. For a border, measure the strip, not the whole bed.
• Rounding too early: Do the full calculation, then round up to the nearest quarter yard. Rounding down leads to a shortage.

Another common misconception is that pea gravel is measured by weight when ordering. In most regions, bulk suppliers quote by the cubic yard, not by the ton. The weight is only relevant for transport and spreading effort. If a supplier quotes by the ton, multiply the cubic yards by about 1.4 to get tons.

Cost and Budget Considerations

The price of pea gravel varies widely by region and source, so the calculator cannot give a dollar figure. However, you can estimate cost by multiplying the cubic yards by the local per-yard price. As a rough guide, bulk pea gravel often ranges from $30 to $60 per cubic yard, while bags cost more per volume – often $5 to $8 per 0.5 ft³ bag, which translates to $270–$430 per cubic yard. Delivery fees are often separate, so check with local suppliers.

For a 10×10 ft area at 3 inches deep (0.93 yd³), bulk gravel would cost roughly $30–$60, plus delivery. Bags would cost $250–$400. For larger areas, the savings with bulk are significant. Always get quotes from at least two suppliers, and confirm whether the price includes delivery and spreading.

Alternatives to Pea Gravel

Pea gravel is popular for its smooth texture and rounded appearance, but it is not the only option. Crushed stone (angular pieces) locks together better and is less likely to shift underfoot, making it a better choice for driveways or high-traffic paths. Decomposed granite compacts into a firm surface, ideal for patios. River rock is larger and more decorative, but harder to walk on. Mulch is cheaper and organic, but needs replacing every year.

When choosing, consider the project’s purpose. For a play area, pea gravel is soft and safe. For a driveway, crushed stone is more stable. For a garden path, decomposed granite offers a firm, natural look. The calculator works for any of these materials – just use the same volume formula.

Frequently Asked Questions

How many square feet does a cubic yard of pea gravel cover?
At a 3-inch depth, one cubic yard covers about 108 square feet (since 1 yd³ = 27 ft³, and 27 ft³ / 0.25 ft = 108 ft²). At 2 inches, it covers 162 ft²; at 4 inches, 81 ft².

Can I use this calculator for a circular area?
Yes. Measure the radius in feet, calculate the area as π × r², then multiply by depth in inches and divide by 324. For example, a 10-ft diameter circle (radius 5 ft) at 3 inches deep is π × 25 × 3 / 324 ≈ 0.73 yd³.

Should I add extra gravel for settling?
Yes, add 5–10% to the calculated volume. Pea gravel settles slightly after rain or foot traffic, and you will want enough to top up after a few weeks.

How deep should pea gravel be for a walkway?
For a residential walkway, 2–3 inches is typical. For areas with heavy foot traffic or where you want to suppress weeds, 3–4 inches is better. Always lay landscape fabric underneath to prevent weeds from growing through.

What is the weight of a cubic yard of pea gravel?
Approximately 2,800 to 3,000 pounds (1.4 to 1.5 tons), depending on moisture content and stone size. This is useful for estimating delivery weight, but volume is what you order.

Can I mix pea gravel with sand for a base?
Yes, a mix of pea gravel and sand is sometimes used for paver bases, but the proportions depend on the project. For a simple path, pure pea gravel works fine. For a patio base, consult a landscaping professional for the correct mix and compaction.

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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