Potting Soil Calculator
Calculate the volume of potting soil needed for your containers, raised beds, and planters
Calculate Potting Soil Volume
Rectangular Container Dimensions
Container Settings
How many containers to fill
Leave 20% for roots and watering
Volume Formulas
where r = bottom radius, R = top radius
Example Calculation
Rectangular Raised Bed
Dimensions: 120cm × 80cm × 30cm
Quantity: 1 container
Fill percentage: 80% (leave room for watering)
Calculation
Volume = 120 × 80 × 30 = 288,000 cm³
Adjusted for 80% fill = 288,000 × 0.8 = 230,400 cm³
Soil needed = 230.4 liters
Container Types
Soil Mix Guide
Potting Tips
Fill containers 80% to leave room for watering
Add drainage holes to prevent waterlogging
Use quality potting mix for better results
Consider plant root space requirements
Mix in slow-release fertilizer if needed
Understanding Container Volume Calculations
Container Shapes Explained
Rectangular Containers
Used for raised beds, window boxes, and rectangular planters. The volume is calculated using the simple formula: length × width × depth.
Round Containers
Cylindrical pots and barrels. Volume is calculated using the cylinder formula: π × radius² × depth.
Flower Pots (Truncated Cone)
Traditional tapered pots that are wider at the top than the bottom. Uses the truncated cone formula for accurate volume calculation.
Planning Considerations
Fill Percentage
Don't fill containers completely. Leave 10-20% space for watering and root expansion. Soil may also settle over time.
Soil Compression
Soil volume can change when compressed or kept loose. These calculations provide a good starting estimate.
Existing Plants
If transplanting existing plants, account for root ball volume which will displace soil.
Soil Purchase Guide
Small Projects
Up to 50 liters: Buy bagged potting soil from garden centers. More convenient for small quantities.
Medium Projects
50-500 liters: Consider bulk bags or multiple large bags. Compare prices per liter for best value.
Large Projects
500+ liters: Bulk delivery is most economical. Order 10-15% extra to account for settling and future needs.