Topsoil Calculator

The formula

Coverage and yield assumptions

Bagged topsoil is commonly sold in 0.75 cu ft (about 40 lb) bags; garden soil and raised-bed mixes in 1–2 cu ft bags. Loose screened topsoil weighs roughly 1.0–1.3 tons per cubic yard depending on moisture and clay content; the calculator uses 1.1.

How much depth do you need?

For new lawns, 4–6 in of good topsoil over loosened subsoil gives roots room to grow. Overseeding an existing lawn needs only a 1/4–1/2 in top dressing. Vegetable beds benefit from 8–12 in of rich soil, and raised beds are filled to their full height. Penn State Extension recommends testing soil before amending so you know what pH and nutrient changes are needed.

Topsoil, garden soil and fill dirt

Fill dirt is subsoil with little organic matter, used for grading and filling holes. Screened topsoil has stones and roots removed and is good for lawns. Garden soil or blended mixes contain compost for planting. Raised-bed mix is lighter and drains better. For large leveling jobs, use fill for the bottom layers and topsoil only on the top 4–6 in.

Settling and compaction

Loose soil settles 10–20% as it is watered and walked on. When filling depressions, overfill slightly and roll the area. Avoid working soil when it is wet, which destroys its structure and creates clods.

Delivery and spreading

• One cubic yard covers about 81 sq ft at 4 in deep.
• Have it dumped on a tarp near the work area.
• Spread with a landscape rake, then lightly roll before seeding.
• Grade soil to slope away from the house foundation.

Common mistakes to avoid

• Using fill dirt for the top layer of a lawn.
• Not allowing for settling after watering.
• Grading soil toward the house foundation.
• Spreading soil when it is wet and sticky.
• Skipping a soil test before amending.

Waste factor

10% accounts for settling and uneven ground. Use 15–20% for filling low areas that will compact a lot, and 5% for top dressing.

Imperial and metric

Switch the toggle above the inputs to enter ft ↔ m, in ↔ cm. The page converts metric entries to imperial before calculating, using NIST factors (1 ft = 0.3048 m, 1 in = 2.54 cm), and shows key results in both systems.

Worked examples

Leveling 20 × 10 ft, 4 in

Inputs: area length 20 ft; area width 10 ft; topsoil depth 4 in; waste factor 10%.

Result: You need 2.72 cubic yards of topsoil.

• Units to buy (rounded up): 2.75 cu yd
• Area: 200 sq ft (18.6 m²)
• Volume: 73.3 cu ft (2.08 m³)
• Approx. weight: 2.99 tons
• 0.75 cu ft bags: 98

New lawn 50 × 30 ft, 4 in

Inputs: area length 50 ft; area width 30 ft; topsoil depth 4 in; waste factor 10%; cost per unit $45.

Result: You need 20.37 cubic yards of topsoil.

• Units to buy (rounded up): 20.5 cu yd
• Area: 1,500 sq ft (139.4 m²)
• Volume: 550 cu ft (15.57 m³)
• Approx. weight: 22.41 tons
• 0.75 cu ft bags: 734
• Estimated material cost: $922.50

Raised bed 8 × 4 ft, 12 in

Inputs: area length 8 ft; area width 4 ft; topsoil depth 12 in; waste factor 10%.

Result: You need 1.3 cubic yards of topsoil.

• Units to buy (rounded up): 1.5 cu yd
• Area: 32 sq ft (3 m²)
• Volume: 35.2 cu ft (1 m³)
• Approx. weight: 1.43 tons
• 0.75 cu ft bags: 47

Quick reference for common sizes

The table repeats the first worked example at smaller and larger sizes, keeping every other setting the same, so you can see how the topsoil calculator result scales.

Limitations

Weight depends heavily on moisture and soil type. Volume is the reliable number for ordering. The calculator assumes an even depth.