Dirt Calculator

How much dirt do I need?

The amount of dirt you need is the volume of the space you want to fill, plus extra for the way soil settles. Bulk dirt is sold by the cubic yard (or by the ton), and bagged soil by the cubic foot, so the calculator gives you all three: cubic yards to order, an approximate weight, and the number of bags.

Common jobs include raising a low spot or regrading away from a house, filling a hole left by a removed tree or pool, backfilling along a wall or trench, building up the ground before a patio base, and filling raised beds. For jobs that end up under a lawn or garden, many people order fill dirt for the bulk of the depth and finish with a few inches of topsoil, so run the calculator once for each layer.

How to measure

• Area: measure length and width in feet (or metres). For a round hole or tree ring, measure the diameter. For odd shapes, add up the areas of simple pieces and use Known area.
• Depth: measure the finished depth you want to add. On sloping ground, use a string line and a tape at several points and average them. For a hole, take its average depth, not the deepest point.
• Layers: if the fill will be topped with sod, topsoil, gravel or pavers, subtract their thickness from the depth of dirt.

Dirt calculator formula

For a circle, use π × (diameter ÷ 2)² for the area. In metric, multiply metres × metres × depth in metres to get cubic metres, then multiply by the density in tonnes per cubic metre. The calculator shows the weight of the loose dirt you order, since that is what a truck or trailer carries.

Worked examples

Leveling a low area: a 20 × 10 ft patch needs 6 inches of fill dirt, with a 15% compaction allowance.

1. Volume in place: 20 × 10 × 6 ÷ 12 = 100 cu ft, or 100 ÷ 27 = 3.70 yd³.
2. With 15% allowance: 100 × 1.15 = 115 cu ft, and 115 ÷ 27 = 4.26 yd³ to order.
3. Weight at 1.2 tons per cubic yard (loose, dry fill): 4.26 × 1.2 = about 5.1 tons, or roughly 10,200 lb.
4. In bags: 115 ÷ 0.75 = 153.3, so 154 bags of 0.75 cu ft, or 115 bags of 1 cu ft. At this size, bulk delivery is usually far more practical.

Raising the grade: a 30 × 15 ft area raised 4 inches is 150 cu ft (5.56 yd³) in place. With a 20% allowance for compacting in layers, order about 6.7 yd³, which is about 8 tons at 1.2 tons per yard.

Metric: a 6 × 3 m area filled 15 cm deep is 2.7 m³ in place, or 3.1 m³ with 15% extra, about 4.4 tonnes at 1.42 t/m³.

Compaction allowance for fill dirt

Dirt delivered by the truck is loose. Once it is spread, watered, walked on or run over with a plate compactor, the air gaps close and the same soil takes up less space. If you order exactly the finished volume, the filled area ends up low. The compaction allowance adds extra loose dirt to make up the difference.

How much soil shrinks depends on its type, moisture and how hard it is compacted. A 10% to 25% allowance is a common planning range for fill dirt, with clay-rich soil and well-compacted fill toward the upper end. Topsoil for beds that is only raked and lightly firmed settles less, so 5% to 10% is often enough. For best results, spread fill in thin layers (lifts) a few inches thick and compact each one, rather than dumping the full depth at once. Fill that will support a slab, footing, driveway or retaining wall should meet the specification from your engineer or contractor.

How much does dirt weigh?

Use weight to check what a pickup or trailer can safely carry, or when a supplier sells by the ton. The soil type menu loads one of these rounded planning figures, which you can overwrite:

These are assumptions for planning, not measured values for any particular product: loose, dry dirt is roughly 2,000 to 2,700 lb per cubic yard, and water, clay and stones make it heavier while organic matter makes it lighter. The metric column is a unit conversion of the US figure. A small load can still exceed a pickup's payload, so check your vehicle's rating before collecting dirt yourself.

Bags of dirt and topsoil

Bagged topsoil and garden soil are sold by volume. Common US sizes include 0.75 cu ft bags (which often weigh around 40 lb) and 1 cu ft bags; check the label, as products vary. One cubic yard equals 36 bags of 0.75 cu ft or 27 bags of 1 cu ft. In metric mode, the calculator counts 25 L and 50 L bags (1 m³ = 1,000 L, so 40 bags of 25 L). Bags make sense for raised beds and small top-ups; past a yard or two, a bulk delivery is usually easier and often cheaper.

Fill dirt vs topsoil

• Fill dirt is subsoil with little organic matter. It packs down firmly and stays put, which makes it the right choice for raising grade, filling holes and backfilling. It is usually one of the cheaper landscape materials, but it is poor for growing plants.
• Topsoil contains organic matter and supports roots, so it belongs on top: a few inches under new sod or seed, and in garden beds. Because organic matter decomposes, topsoil keeps settling and is not suited to structural fill.
• Screened or blended soils (topsoil mixed with compost or sand) are sold for beds and lawns; their weight and settling vary more, so ask the supplier.

Ask whether fill dirt is clean (free of debris, roots and trash) before you accept a load. For volumes of other materials, use the cubic yard calculator; for a stone base or driveway, use the gravel calculator.

Frequently asked questions

How much dirt do I need?

Multiply length × width × depth in feet to get cubic feet, divide by 27 for cubic yards, then add a compaction allowance. For example, filling a 20 × 10 ft area 6 inches deep takes 100 cu ft, or 3.7 cubic yards in place; with 15% extra, order about 4.3 cubic yards.

What is the difference between fill dirt and topsoil?

Fill dirt is subsoil from below the topsoil layer: mostly sand, clay, silt and small stones with little organic matter. It is used to raise grade, fill holes and backfill, and it compacts into a stable base. Topsoil is the darker upper layer with organic matter that plants need. It is used for lawns, gardens and beds, usually as the top few inches over fill, and is not a good structural fill because the organic matter breaks down and settles.

How much does a cubic yard of dirt weigh?

As a rough planning range, a cubic yard of loose, dry topsoil or fill dirt weighs about 2,000 to 2,700 lb (1 to 1.35 US tons). Moist or clay-heavy soil can weigh about 3,000 lb or more. Ask your supplier for their figure, especially if you are checking a truck or trailer payload.

How many bags of dirt are in a cubic yard?

A cubic yard is 27 cubic feet, so it equals 36 bags of 0.75 cu ft, 27 bags of 1 cu ft or 18 bags of 1.5 cu ft. Bag sizes vary by brand, so check the volume on the label. Bulk delivery is usually more practical once a job needs more than a yard or two.

How much extra fill dirt should I order for compaction?

Loose fill shrinks when it is compacted or settles over time, so order more loose volume than the finished space. A 10% to 25% allowance is a common planning range; clay-rich soil and heavily compacted fill can need more. For fill under slabs, footings or driveways, follow the specification from your engineer or contractor.

How many square feet does a yard of dirt cover?

One cubic yard covers about 324 sq ft at 1 inch, 108 sq ft at 3 inches, 81 sq ft at 4 inches, 54 sq ft at 6 inches and 27 sq ft at 12 inches, before any compaction allowance.

Related calculators

• Cubic Yard CalculatorCubic yards, cubic feet and cubic metres for any material, with waste, weight and bags.
• Mulch CalculatorMulch in bags or cubic yards, and which is cheaper with delivery.
• Gravel CalculatorVolume and weight for driveways and bases, with presets for common gravel types.
• Paver CalculatorPavers to buy, base gravel, bedding sand and edge restraint for a patio.