Raised Bed Soil Calculator
Figure out exactly how much soil, compost, and amendments you need to fill your raised garden beds. Results in cubic feet, cubic yards, gallons, and bag counts.
How It Works
The volume of soil you need is simply the volume of your raised bed: length × width × depth. Convert depth from inches to feet by dividing by 12. The calculator then splits the total volume into the components of your chosen soil mix recipe.
Choosing the Right Soil Mix
Balanced (60/30/10): Great all-purpose mix for most vegetables. Topsoil provides structure, compost adds nutrients, perlite improves drainage.
Mel's Mix (1/3 each): Made famous by Square Foot Gardening. Lightweight and nutrient-rich. Peat moss retains moisture but is not renewable — consider coir as an alternative.
Organic (50/30/20): High compost content for heavy feeders. Coir is a sustainable peat alternative.
Lightweight (40/30/30): Extra perlite for containers and beds where drainage is critical (e.g., roofs, wet climates).
Tips
Buy in bulk: Soil is much cheaper by the cubic yard than by the bag. One cubic yard = 27 cu ft = about 13–14 two-cubic-foot bags.
Don't use garden soil alone: It compacts in raised beds and drains poorly. Always mix with compost and a lightening agent.
Leave 1–2 inches at the top: Fill beds to within 1–2 inches of the rim to leave room for watering and mulch.