Use inside planter dimensions for fill and outside dimensions for board cuts.
Can the same outside dimensions be used unchanged for both material quantities?
Use the matching calculator
Use this decision sequence
- Use the supplied outside length and width to read the specified wall cut arrangement.
- Deduct both opposing wall thicknesses to obtain inside length and width.
- Use the specified finished fill height rather than automatically using the untrimmed stacked board height.
- Keep bottom, supports and lining outside the open-bottom wall model unless separately specified.
Keep the quantities distinct
| Quantity or assumption | How to use it |
|---|---|
| Long wall cuts | Full outside length in the supplied arrangement. |
| Short wall cuts | Fit between the long walls. |
| Fill footprint | Uses inside dimensions, not either wall cut directly. |
Worked comparison
An illustrative 2 m by 1 m outside container with 0.05 m walls has a 1.9 m by 0.9 m inside plan. At 0.5 m specified fill height, capacity is 0.855 m³ rather than the 1 m³ outside envelope. Boards of 0.2 m face height need three courses before top trim, but that 0.6 m stacked height should not silently replace the specified finished height.
Check before using the estimate
Wall sizes and arrangement are supplied; support, fixing, lining and material suitability are not selected.
All dimensions, product properties, prices and specifications in this example are illustrative arithmetic inputs. Use the values from your measured plan, selected product data sheet and supplier quote. This guide does not choose construction specifications or certify safety.
Calculation and scope checked 2026-10-04. Methods and scope.