Raised Bed Soil Calculator - Calculate Cubic Yards, Feet & Bags

Bed Length (Feet)

Standard garden beds are usually 4, 6, or 8 ft

Bed Width (Feet)

3 to 4 ft allows easy reaching from both sides

Bed Depth / Soil Height (Inches)

Typical depth: 6"–12" for greens; 12"–18" for root crops

Number of Beds

Calculate for multiple identical beds

Soil Blend / Recipe

Breaks down exact amounts needed per component

Settling Buffer

Fresh soil settles 10-15% after the first watering

Soil Required

35.2

Cubic Feet (cu ft)

1.30

Cubic Yards (cu yd)

2.0 cu ft Bags

Bags Needed by Size

Bag Size	Common Mixes / Amendments	Total Bags Needed
0.75 cu ft	Bagged manure, organic amendments	47 bags
1.0 cu ft	Compost, worm castings, vermiculite	36 bags
1.5 cu ft	Bagged raised bed mix, soil blends	24 bags
2.0 cu ft	Standard potting soil, topsoil bags	18 bags

Component Breakdown: Equal-Thirds Mix

How to Calculate Raised Bed Soil Volume

Calculating how much soil you need for your raised garden bed comes down to geometric volume converted to standard retail units (cubic feet or cubic yards).

Volume (Cubic Feet) = Length (ft) × Width (ft) × [Depth (inches) ÷ 12]
Volume (Cubic Yards) = Volume (Cubic Feet) ÷ 27

For example, a classic 8 ft by 4 ft raised bed with a 12-inch depth:

8 ft × 4 ft × 1 ft (12 inches) = 32 cubic feet
32 ÷ 27 = 1.19 cubic yards
Adding a 10% settling factor gives 35.2 cubic feet (about 18 bags of 2 cu ft soil).

Bulk Delivery vs. Bagged Soil: Which is Cheaper?

As a rule of thumb:

Under 1 cubic yard (under 27 cu ft): Buy bags from your local nursery or home center. Buying 10 to 14 bags is clean, easy to transport in an SUV or car trunk, and avoids bulk delivery drop fees ($40–$100).
Over 1.5 to 2 cubic yards (over 40–54 cu ft): Bulk delivery from a local landscape supplier is almost always significantly cheaper per yard (typically $35 to $65 per cubic yard vs. $100 to $160 per yard in individual retail bags).

The Hugelkultur Base: How to Save 30%–50% on Deep Beds

If your raised beds are 18 to 32 inches deep, you do not need to fill the entire bed with premium potting soil. The root systems of most annual vegetables (tomatoes, peppers, greens) rarely go deeper than 12 to 14 inches.

Bottom Layer (30%–40%): Hardwood logs, thick branches, untreated wood chunks, and cardboard. As this wood slowly rots over 3–5 years, it acts as a subterranean sponge holding moisture and feeding beneficial mycorrhizal fungi.
Middle Layer (20%): Grass clippings, dry leaves, straw, or unfinished compost.
Top Layer (10–12 inches): High quality raised bed mix or equal-thirds blend where your plants' roots actively grow.

Recommended Soil Blends

Equal-Thirds Mix (1/3 compost, 1/3 peat/coir, 1/3 vermiculite): 1/3 blended compost (from 3+ diverse sources), 1/3 coarse horticultural vermiculite, and 1/3 peat moss or coconut coir. Lightweight, retains water, resists compaction.
Traditional 50/50 Garden Mix: 50% screened topsoil and 50% finished organic compost. Economical and provides good mineral mass.