Open Box Liner Blank calculator.
Size one rectangular liner blank for an open rectangular box with specified depth and edge allowance.
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.
Size one rectangular liner blank for an open rectangular box with specified depth and edge allowance. Blank dimensions only, not a waterproofing design or installation method.
A worked example
Illustrative inputs only. Product properties and design dimensions are not recommendations for your project.
- Inside base length
- 2 m
- Inside base width
- 1 m
- Specified covered depth
- 0.5 m
- Specified extra allowance at every outer edge
- 0.1 m
Rectangular liner blank area: 7.04 m²
An uncut rectangular blank with corner surplus. Does not provide folding, joining, drainage, waterproofing or material-compatibility instructions.
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.
Blank dimensions only, not a waterproofing design or installation method.
Method: dimensional arithmetic and user-supplied specifications. Software checks: 2026-10-04. Calculation and review policy.