Soil Calculator — How Much Soil Do I Need?
Enter your dimensions and depth to instantly calculate cubic yards, weight, bag counts, and cost — for any soil type.
🌱 Soil / Topsoil Calculator
💡 New garden beds typically need 6 inches of fresh topsoil. For topdressing an existing lawn or bed, 4 inches is sufficient.
💡 Use this tab for circular tree rings, round planters, or circular herb gardens.
💡 Use this tab if you already have square footage from a landscape plan or contractor quote.
💡 Standard raised beds are 8–12 inches deep. Enter the interior height of your planter box walls for the most accurate estimate. Most vegetables need 8+ inches of root depth.
How to Calculate Soil for Your Garden
Whether you're building a new raised bed, refreshing an old garden, or filling a large planting area, estimating soil accurately saves you extra trips to the store — or the embarrassment of a short load sitting in your driveway. Here's how to use this calculator:
- Choose your shape tab. Rectangular Bed handles standard garden beds and borders. Circular Bed covers tree rings and round planters. Custom Area is for when you already have square footage from a site plan. Raised Bed / Planter Box is for framed raised beds where you fill to a specific wall height.
- Enter your dimensions. Measure the interior of your bed (not the outside of the frame). For a raised bed, use the interior length and width. For irregularly shaped areas, break them into rectangles and use the Custom Area tab with total square footage.
- Set your depth. Use 4 inches for topdressing lawns or existing beds. Use 6 inches for new in-ground garden beds — the recommended default. Use 8–12 inches for raised beds and deep-rooted vegetables like tomatoes, carrots, and squash. The depth preset buttons let you fill in common values with one click.
- Select your soil type. Each type has a different density, which changes the weight and bag count. Potting mix (800 lbs/yd³) is far lighter than clay soil (2,800 lbs/yd³). Volume is the same — only weight, bag count, and cost differ.
- Enter your price per yd³. The calculator auto-fills a reasonable default when you select a soil type. Get a quote from your local nursery or landscape supply for accuracy. Prices vary significantly by region and type.
- Click Calculate. You'll see cubic yards needed (the primary ordering unit for bulk soil), cubic feet, weight in lbs and tons, 40-lb bag count, estimated cost, and a bulk vs. bags comparison table.
Worked example: A 4 ft × 8 ft raised bed filled to 6 inches. Volume = (4 × 8 × 6/12) ÷ 27 = (4 × 8 × 0.5) ÷ 27 = 16 ÷ 27 = 0.59 cubic yards. Using Topsoil (2,200 lbs/yd³): Weight = 0.59 × 2,200 = 1,298 lbs = 0.65 tons. Bags needed (40 lb): 1,298 ÷ 40 = 33 bags. At $35/yd³ bulk, cost = 0.59 × $35 = ~$21.
Planning more than soil? Check the Mulch Calculator for the top-dressing layer, and the Gravel Calculator for path fill or drainage layers. If you're pouring concrete edging around your beds, use the Concrete Calculator.
Soil Types Explained
Not all soil is the same — and choosing the wrong type for your project wastes money and can stunt plant growth. Here's what each type is best for:
| Soil Type | lbs/yd³ | Best For | Avg. Bulk Price |
|---|---|---|---|
| Topsoil | 2,200 | General garden beds, lawn topdressing, fill | $25–$45/yd³ |
| Garden Soil Mix | 1,800 | In-ground vegetable gardens, flower beds | $35–$60/yd³ |
| Compost | 1,000 | Amending existing soil, raised beds, mulching | $40–$70/yd³ |
| Potting Mix | 800 | Containers, pots, very small raised beds | $50–$90/yd³ |
| Fill Dirt | 2,400 | Grading, leveling, non-growing applications | $10–$30/yd³ |
| Sandy Loam | 2,600 | Drainage-needing beds, root vegetables | $25–$50/yd³ |
| Clay Soil | 2,800 | Structural fill, erosion control (poor for plants) | $15–$35/yd³ |
ℹ️ Densities are approximate. Moisture content significantly affects real-world weight.
Topsoil vs. Garden Soil — What's the Difference?
Topsoil is the top 2–8 inches of native earth — it contains organic matter but quality varies widely by source. Screened topsoil removes rocks and clumps; triple-screened topsoil is the finest grade. Garden soil (also called "garden mix" or "planting mix") is topsoil blended with compost and sometimes perlite or peat moss for improved drainage, aeration, and nutrient content. For in-ground vegetable beds, garden soil mix outperforms plain topsoil. For bulk filling or leveling, plain topsoil is the economical choice.
Never Use Potting Mix for Large Areas
Potting mix is designed for containers — it's lightweight, fast-draining, and expensive per cubic yard. Using it to fill a large raised bed costs 2–3× more than a quality garden mix for no additional benefit. Save potting mix for pots, window boxes, and hanging baskets. Use garden soil mix or a 50/50 topsoil-compost blend for raised beds.
How Much Soil for Raised Beds
Raised beds are the most common reason people need to calculate soil volume. Here are amounts for the most popular sizes:
| Bed Size (L × W) | Depth 6" | Depth 8" | Depth 12" |
|---|---|---|---|
| 4 ft × 4 ft | 0.30 yd³ | 0.40 yd³ | 0.59 yd³ |
| 4 ft × 8 ft | 0.59 yd³ | 0.79 yd³ | 1.19 yd³ |
| 4 ft × 12 ft | 0.89 yd³ | 1.19 yd³ | 1.78 yd³ |
| 4 ft × 16 ft | 1.19 yd³ | 1.58 yd³ | 2.37 yd³ |
| 6 ft × 8 ft | 0.89 yd³ | 1.19 yd³ | 1.78 yd³ |
| 6 ft × 12 ft | 1.33 yd³ | 1.78 yd³ | 2.67 yd³ |
These are volumes only — weight and bag count depend on soil type. Use the calculator above with your exact dimensions for the precise number. Always add 10–15% extra for settling; soil compresses over time, especially after watering.
The Mel's Mix Formula (Best Raised Bed Soil)
The gold standard for raised bed filling is "Mel's Mix" from the Square Foot Gardening method: ⅓ compost, ⅓ peat moss (or coco coir), ⅓ coarse vermiculite. This blend drains well, resists compaction, and grows vegetables exceptionally. To calculate how much of each you need: calculate total yd³ with this tool, then divide by 3 for each component. For a 4×8 bed at 12 inches, total = 1.19 yd³ → buy 0.4 yd³ each of compost, peat/coir, and vermiculite.
Soil Buying Guide
Bulk vs. Bagged Soil
The right choice depends almost entirely on project size:
- Bulk topsoil or garden mix (loose, by the cubic yard) is the right call for anything over 1–2 cubic yards. Delivered by dump truck, it costs $25–$70/yd³ depending on type and location. Minimum delivery is usually 1–3 yards. You need to designate a drop zone — bulk soil is heavy and delivery trucks can't access backyard areas.
- 40-lb bagged topsoil (~0.75 cu ft per bag) runs $3–$6 per bag at home improvement stores. That's $108–$216 per cubic yard — 3–5× the cost of bulk. But bags require no delivery minimum, no heavy equipment, and can reach any backyard via wheelbarrow.
- 1 cu ft bagged soil or compost runs $6–$12 per bag ($162–$324/yd³). Premium brands (Black Kow, Espoma, etc.) cost more but include higher compost content.
Break-even point: For most areas, once you need more than 1–2 cubic yards, bulk delivery is cheaper even after delivery fees. The calculator shows the exact dollar comparison for your project.
Where to Buy
- Local landscape supply yards — Best prices on bulk. Will deliver. Often let you pick up with a truck.
- Home improvement stores (Home Depot, Lowe's) — Convenient bags. Good for small projects and premium mixes.
- Garden centers / nurseries — Best quality soil and compost. More expensive but often better screened and sourced.
- Online delivery (by the bag) — Good for specialty mixes (seed starting, cactus, orchid). Not practical for bulk filling.
Regional Price Ranges (2026)
- Northeast (NY, MA, CT): $40–$65/yd³ delivered topsoil
- Southeast (FL, GA, NC): $25–$50/yd³ delivered
- Midwest (OH, IL, MN): $30–$55/yd³ delivered
- South-Central (TX, OK): $25–$45/yd³ delivered
- West Coast (CA, WA, OR): $45–$80/yd³ delivered
Pickup from a landscape yard runs $10–$20/yd³ cheaper than delivered. Minimum delivery loads are typically 1–3 cubic yards; expect a small-load fee of $50–$100 for deliveries under 5 yards.
How Deep Should Garden Soil Be?
Soil depth is the single most important variable — it determines both the amount you need and whether your plants will thrive:
- Topdressing lawns and beds: 4 inches. A light 4-inch layer of compost or screened topsoil refreshes nutrients and improves soil structure without burying existing plants. Apply in early spring or fall and let earthworms work it in. Lightly rake level; do not pile against plant stems.
- New in-ground garden beds: 6 inches. Six inches of fresh topsoil or garden mix gives annual vegetables and flowers enough root space for a full growing season. Mix with the existing native soil below (till or loosen to 8–10 inches total) for best drainage.
- Raised beds for vegetables: 8–12 inches. Tomatoes, peppers, eggplant, and most fruiting vegetables need 10–12 inches of loose, well-draining soil. Leafy greens (lettuce, spinach, basil) do fine with 6–8 inches. Root vegetables (carrots, beets, parsnips) need 12–18 inches of loose, rock-free soil. Most standard raised beds are 8–12 inches tall — this matches the fill height you should use in the calculator.
- Deep planters and large containers: 12–18 inches. Large containers and deep planters that host perennials, small shrubs, or fruiting trees need 12–18 inches of quality potting mix or a topsoil-compost blend. Ensure drainage holes are unobstructed — containers without drainage become waterlogged.
- Lawn leveling and sodding: 4–6 inches. When preparing ground for new sod or seeding, you need 4–6 inches of quality topsoil. Skip this and your lawn will struggle in summer heat and compacted soil. Till the existing ground before adding new topsoil for best root-to-soil contact.
Frequently Asked Questions
A standard 4 ft × 8 ft raised bed filled to 6 inches deep requires 0.59 cubic yards of topsoil. The formula: (4 × 8 × 6/12) ÷ 27 = (4 × 8 × 0.5) ÷ 27 = 16 ÷ 27 = 0.59 yd³. In 40-lb bags of topsoil: 0.59 × 2,200 ÷ 40 = about 33 bags. At 8 inches deep, the same bed needs 0.79 yd³ or about 44 bags. Always add 10% for settling.
It depends on bag size. For 40-lb bags of topsoil (approximately 0.75 cu ft each): one cubic yard = 27 cu ft, so you need about 36 bags per cubic yard. For 1 cu ft bags: you need exactly 27 bags per cubic yard. Bulk topsoil at $35/yd³ is far cheaper than bagged — 36 bags at $4 each costs $144, versus $35 for the same volume in bulk.
Topsoil is screened native earth — cheap, heavy (2,200 lbs/yd³), and variable in quality. Good for bulk filling and leveling. Garden soil mix is topsoil blended with compost and often perlite — better drainage, more nutrients, lighter. Best for in-ground vegetable and flower beds. Compost is fully decomposed organic matter — the lightest (1,000 lbs/yd³), most nutrient-dense, and most expensive per yard. Use compost to amend existing soil or as one component in a raised bed mix. For large raised beds, the ideal blend is ⅓ topsoil, ⅓ compost, ⅓ drainage amendment (perlite or coarse sand).
Most vegetables grow well in 8–12 inches of quality soil. Leafy greens (lettuce, spinach, herbs) need a minimum of 6 inches. Fruiting vegetables (tomatoes, peppers, cucumbers) need 10–12 inches. Root vegetables (carrots, parsnips, beets) need 12–18 inches of loose, rock-free soil. For a general-purpose raised bed that grows everything, fill to 10–12 inches — it accommodates almost all common vegetables and herbs without needing separate beds.
For projects over 1 cubic yard (about 36–40 bags), bulk delivery is almost always cheaper — even after delivery fees. A typical bulk delivery of 2–3 yards costs $70–$150 delivered; the same amount in bags costs $280–$600. The catch: bulk requires a dump-truck-accessible drop zone. Use bags when: your project is under 1 yard, you need backyard access a truck can't reach, or you need a premium specialty mix not available in bulk. Use the comparison table in this calculator for your exact project cost.
One cubic yard of topsoil weighs approximately 1.1 tons (2,200 lbs). Dry topsoil can weigh as little as 1,800 lbs/yd³; wet, clay-heavy topsoil can exceed 2,800 lbs/yd³. For comparison: garden soil mix weighs about 1,800 lbs/yd³; compost weighs only 1,000 lbs/yd³; potting mix is just 800 lbs/yd³. Weight matters for delivery (truck weight limits) and for raised beds sitting on decks or rooftops — a 4×8 bed at 12 inches of topsoil weighs over 1,600 lbs, which most residential decks can't safely support without structural reinforcement.