Soil Calculator: Cubic Feet for Garden Beds

Soil Calculator: Cubic Feet for Garden Beds

Calculate the cubic feet of soil needed for any garden bed. Measure length, width, and depth in feet. Multiply all three.

Formula

Volume (ft³) = Length (ft) × Width (ft) × Depth (ft)

For depth in inches, divide by 12 to convert to feet.

Common Garden Bed Sizes

Bed Size	Depth	Soil Needed (ft³)	Bags (2 ft³ each)
4’ × 4’	6”	8	4
4’ × 8’	6”	16	8
4’ × 8’	12”	32	16
3’ × 6’	8”	12	6
4’ × 12’	6”	24	12

Recommended Soil Depths

• Vegetables: 12–18 inches (lettuce, herbs need less; tomatoes, peppers need more)
• Flower beds: 6–12 inches
• Lawn top dressing: 1–2 inches
• Trees and shrubs: 18–24 inches

Example Calculation

A raised bed measures 4 ft × 8 ft with 12 inches of depth.

• Length = 4 ft
• Width = 8 ft
• Depth = 12 inches ÷ 12 = 1 ft
• Volume = 4 × 8 × 1 = 32 ft³ of soil
• That equals 32 ÷ 27 = 1.19 cubic yards

Buying Soil

Bagged soil sells by the cubic foot (1, 1.5, or 2 ft³ bags). Bulk soil sells by the cubic yard (27 ft³). For beds larger than 20 ft³, bulk delivery is more cost-effective.

Use our Cubic Feet Calculator to find the exact amount of soil for your project.