Garden Bed Calculator
Calculate the exact area, soil volume needed, and how many plants will fit in your garden bed. Plan your raised bed or in-ground garden with precision - get accurate measurements for ordering materials and spacing plants perfectly.
About This Calculator
This free garden bed calculator helps you plan raised beds and garden plots by calculating exact area, soil volume, and plant count. Whether you're building a new raised bed or refilling an existing one, get precise measurements to purchase the right amount of materials.
What You Can Calculate
- Garden bed area in square feet, meters, and yards
- Soil volume needed in cubic yards and cubic feet
- Number of bagged soil required (1, 2, or 3 cu ft bags)
- Plant count based on spacing requirements
Pro Tips
- Order 10-15% extra soil for settling and compaction
- Keep beds 4 feet wide for easy center access
- Standard raised bed depth is 6-12 inches
- Root vegetables need at least 12 inches of soil
Popular Raised Bed Sizes
| Bed Size | Area | Soil (12" deep) | Best For |
|---|---|---|---|
| 4' x 4' | 16 sq ft | 0.6 cu yd | Small spaces, beginners, square foot gardening |
| 4' x 8' | 32 sq ft | 1.2 cu yd | Most popular size, great for vegetables |
| 3' x 6' | 18 sq ft | 0.7 cu yd | Narrow spaces, easier reach |
| 4' x 12' | 48 sq ft | 1.8 cu yd | Large gardens, row planting |
| 2' x 8' | 16 sq ft | 0.6 cu yd | Against walls/fences, herbs |
Garden Bed Planning Tips
Optimal Width
Keep beds 4 feet wide or less so you can reach the center from either side.
Soil Mix
Fill with 60% topsoil, 30% compost, 10% aeration material.
Depth Matters
Most vegetables need 6-12" of soil. Root crops need 12"+.
Location
Place beds where they get 6-8 hours of direct sunlight daily.
How to Calculate Garden Bed Size and Soil Needs
Planning a new garden bed requires accurate calculations to ensure you have enough soil, the right amount of plants, and optimal spacing. Whether you're building a raised bed, creating an in-ground garden plot, or planning a flower bed, this calculator helps you determine exactly what you need.
Calculating Garden Bed Area
For rectangular beds, multiply length x width. A 4' x 8' bed = 32 square feet. For circular beds, use pi x radius squared (pi is approximately 3.14159). A 6-foot diameter circular bed has a radius of 3 feet, giving an area of about 28.3 square feet.
How Much Soil Do I Need?
To calculate soil volume, multiply the bed area by the depth. For example, a 4' x 8' bed filled 12 inches deep needs:
- Volume: 32 sq ft x 1 ft = 32 cubic feet
- In cubic yards: 32 / 27 = 1.19 cubic yards
- With 10% extra: Order 1.3 cubic yards
Recommended Soil Depths
| Plant Type | Minimum Depth | Recommended |
|---|---|---|
| Lettuce, Herbs, Greens | 6 inches | 8-10 inches |
| Peppers, Beans, Cucumbers | 8 inches | 10-12 inches |
| Tomatoes, Squash | 12 inches | 18 inches |
| Carrots, Potatoes, Root Vegetables | 12 inches | 18-24 inches |
Benefits of Raised Garden Beds
- Better drainage: Excess water drains away, preventing root rot
- Warmer soil: Raised beds warm up faster in spring for earlier planting
- Less weeding: Easier to control weeds with defined boundaries
- Improved soil quality: Fill with ideal soil mix, not native clay or sand
- Easier access: Less bending and kneeling, great for accessibility
- Higher yields: Intensive planting in quality soil produces more food
Related Tools
Check out our Garden Measurement Calculator for unit conversions, or use our Plant Spacing Calculator to determine how many plants fit in your garden.