How to use this calculator
- Measure each rectangular room or non-overlapping floor section. Use the same units within each input.
- Enter the actual product specifications, your chosen allowance and usable quantity already owned. Enter zero explicitly where appropriate.
- Assign rooms to product entries. Matching names alone do not combine products.
- Resolve every incomplete or invalid group. Review the quantity to buy and all assumptions.
- Take the current material's CSV or print summary. Save or back up JSON to continue editing the complete project.
A reproducible test example
18 m², 8% entered allowance and 2.2 m² per box → 19.44 m² plan and nine complete boxes.
These are test inputs, not recommended product values. Use “Try the test example” to inspect them; it replaces the current project only after confirmation when edits are unsaved.
Supported scope and limitations
Area coverage per complete box. Split irregular floors into non-overlapping rectangular sections. This is not a cutting plan and does not calculate adhesive, grout or installation requirements.
Clearing browser storage can remove saved projects. Downloads remain in your files. No account, cloud storage or background upload is provided.
Read the detailed flooring guide · Review calculation methods · Understand local storage
Sources and scope
For definitions of wallpaper match, repeat and packaging, see Brewster's product properties and Graham & Brown's wallpaper FAQ. Product instructions take precedence over generic examples. Unit conversions use the exact international foot (0.3048 m) and US liquid gallon (3.785411784 L); see NIST conversion factors.