Calculate exactly how much soil, compost, and amendments you need to fill raised garden beds. Supports rectangular, circular, and L-shaped beds with custom soil mix ratios. Enter your bed dimensions and get volumes in cubic feet, cubic yards, and bags. Free to use — no signup required.
Planning your first raised bed? Read our complete raised garden bed building guide for step-by-step instructions.
Soil volume for common raised bed sizes at 12 inches deep.
| Bed Size | Cu Ft | Cu Yd | 1 cu ft Bags | 2 cu ft Bags |
|---|---|---|---|---|
| 2 × 4 ft | 8 | 0.30 | 8 | 4 |
| 3 × 6 ft | 18 | 0.67 | 18 | 9 |
| 4 × 4 ft | 16 | 0.59 | 16 | 8 |
| 4 × 8 ft | 32 | 1.19 | 32 | 16 |
| 4 × 12 ft | 48 | 1.78 | 48 | 24 |
| 3 ft diameter (round) | 7.1 | 0.26 | 8 | 4 |
Filling a standard 4×8 foot raised bed to 12 inches deep requires 32 cubic feet of soil — that's about 1.19 cubic yards. Using the All-Purpose mix (60% topsoil, 30% compost, 10% perlite), you'd need roughly 19 cu ft of topsoil, 10 cu ft of compost, and 3 cu ft of perlite. Buying bulk topsoil at $35/yard and bagged compost at $5 per cubic foot, expect to spend about $90–$110 per bed. If you're filling 3 beds, budget around $270–$330 total.
| Material | Typical Price |
|---|---|
| Bulk topsoil (per cu yd) | $25 – $50 |
| Bulk garden compost (per cu yd) | $30 – $60 |
| Bagged topsoil (1 cu ft) | $3 – $6 |
| Bagged compost (1 cu ft) | $4 – $7 |
| Bagged peat moss (3.8 cu ft) | $12 – $20 |
| Bagged perlite (2 cu ft) | $15 – $25 |
| Bagged vermiculite (2 cu ft) | $20 – $30 |
| Coconut coir (1.4 cu ft brick) | $10 – $18 |
Most vegetables do well in 12 inches of soil. Root vegetables like carrots and potatoes prefer 18 to 24 inches. Herbs and lettuce can thrive in as little as 6 to 8 inches. If your bed sits on soil (not concrete or decking), roots can grow deeper than the bed itself.
A good all-purpose mix is 60% topsoil, 30% compost, and 10% perlite or vermiculite. Mel's Mix (equal thirds compost, peat moss, and vermiculite) is popular for square foot gardening. Avoid using 100% garden soil — it compacts too much and drains poorly in a raised bed.
At 12 inches deep, a 4×8 bed holds 32 cubic feet of soil. That's 32 one-cubic-foot bags or 16 two-cubic-foot bags. Buying bulk is usually much cheaper — 32 cubic feet is just under 1.2 cubic yards, which most landscape supply yards deliver for $35–$60 per yard.
Bulk soil is significantly cheaper — typically $30–$50 per cubic yard delivered, versus $3–$6 per cubic foot bagged. If you're filling more than 1 cubic yard (about 2 standard 4×4 beds at 12" deep), bulk delivery almost always saves money. Bags are more practical for small beds or if you need precise mixes.
Yes — many gardeners use the Hügelkultur method, filling the bottom third with rotting logs, branches, straw, or leaves. This saves on soil cost and improves drainage as the organic matter decomposes. Use the "Partial fill" option in this calculator to account for the reduced soil depth.
A single 4×8 foot bed at 12 inches deep costs roughly $40–$70 using bulk soil delivery, or $100–$200 using individual bags from a garden center. Adding compost and amendments increases the total. Filling multiple beds in one bulk order is the most cost-effective approach.
Typical Results
💡 Soil compacts 10–20% after watering — order slightly extra or mound above the rim when filling.
Common Mistakes