Rectangular Planter Casting Shell Material calculator.
Count supplied rectangular shell volume without double-counting the corners where side walls meet.
Your inputs
Use measurements from your plan and properties from your chosen product. Any prefilled values are illustrative.
A clear estimate starts here.
Enter your dimensions and product details to see the quantity and purchase breakdown.
Formula and assumptions
How this calculation works.
Shell volume = outer width × length × height − (width − 2 × side thickness)(length − 2 × end thickness)(height − base thickness). Does not choose wall thickness, reinforcement, waterproofing, strength or handling requirements.
A worked example
Illustrative inputs only. Product properties and design dimensions are not recommendations for your project.
- Selected mixed volume yield per kit or bag
- 10 L/bag
- Outer width
- 0.4 m
- Outer length
- 0.6 m
- Outer height
- 0.3 m
- Already supplied side wall thickness
- 50 mm
- Already supplied end wall thickness
- 50 mm
- Already supplied base thickness
- 50 mm
- Identical shells
- 1
Selected mixed-material packages: 4 packages
Outer volume minus one retained inner cavity; shared wall corners are counted once. No drain openings are assumed. Product suitability, curing, strength and mixing specifications are not selected.
Before you purchase
Use dimensions from your plan and properties from your chosen product. Any design spacing, section or fixing pattern must already be specified.
Does not choose wall thickness, reinforcement, waterproofing, strength or handling requirements.
All dimensions, properties and application patterns are user-supplied. No building-code default is inserted.
Method: dimensional arithmetic and user-supplied specifications. Software checks: 2026-10-06. Calculation and review policy.
Check your purchase assumptions
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