Practical guide · Reviewed September 14, 2026
Choosing a material allowance
An allowance increases the measured need to cover cutting, breakage, touch-ups or installation constraints. It is different from the surplus created by buying whole packs. RoomLedger displays both concepts separately.
No universal percentage
The initial 10% is an editable example, not an industry guarantee. A straight installation in a regular room and a diagonal layout through several doorways may need different allowances. Follow the product label, layout plan and installer advice.
Test two scenarios
A 20 m² floor at 10% allowance requires 22 m² before rounding. At 15% it requires 23 m². If one pack covers 2 m², those scenarios require 11 and 12 packs. The price difference may matter more than the one-square-metre change suggests.
Tile limitations
The tile tool estimates boxes by area. It does not optimise cuts, model grout joints, calculate adhesive or guarantee a layout. Use a physical or CAD layout where cuts and patterns dominate material use.
Keep a clear record
Save your project before ordering. If you later change the allowance, download a new backup and keep the old one if you need a version history. Cloud versioning is not included in this release.
Arithmetic examples are illustrative. Verify measurements and the product label before purchasing.
Use these numbers in a project ↗