Floor underlay.
Measure the layer's coverage area and supplied strip direction or overlap.
Read the right quantitative data
Pack area or roll width and length, and layer thickness if checking a supplied height stack.
Check this ordering assumption
Net pack area and overlapped roll coverage represent different quantity bases.
Keep each layer independent and use only already specified overlap and thickness.
A worked quantity method
This illustrative set of supplied inputs demonstrates Underlayment Calculator. Replace the example measurements and product figures with your own before ordering.
| Supplied input | Metric display | US display |
|---|---|---|
| Underlay supply format | NaN | NaN |
| Length | 4 m | 13.12 ft |
| Width | 5 m | 16.4 ft |
| Effective coverage per roll / pack | 10 m² | 107.6 ft² |
| Waste allowance | 10 % | 10 % |
Packs to purchase: 3 packs
- Floor area
- 20 m²
- Coverage needed
- 22 m²
Your measurement and product-data sheet
Record what you know and mark verified items ready. Notes save on this browser after you edit them. Download a copy before clearing browser data.
Measure the layer's coverage area and supplied strip direction or overlap.
Pack area or roll width and length, and layer thickness if checking a supplied height stack.
Net pack area and overlapped roll coverage represent different quantity bases.
Input for Underlayment Calculator. Record the value with its unit and quantity basis. Available choices: Packs by usable area; Rolls with seam overlap
Input for Underlayment Calculator. Record the value with its unit and quantity basis.
Input for Underlayment Calculator. Record the value with its unit and quantity basis.
Use usable coverage after any specified overlaps.
Input for Underlayment Calculator. Record the value with its unit and quantity basis.
Choose your next calculation
Underlayment Calculator
Estimate underlay packs by effective area or rolls from room width and your specified seam overlap.
Roof Membrane Roll Lap Calculator
Count membrane courses and rolls for supplied roof-plane dimensions and specified side and end laps.
Floor Layer Height Calculator
Add specified layer thicknesses and compare a finished floor height to an adjoining threshold.
Turn the estimate into an order
- Confirm that all quantities use the same measured basis and the selected product's current data.
- Keep different products, finishes and handed variants in separate purchase lines.
- Review exact demand and whole-pack purchase quantities before entering your quoted prices.
- Record compatible stock already on hand, then save the remaining order in your browser project.
Measurement and purchase guides
Other materials in this family
Reviewed 6 October 2026. Geometry and purchase arithmetic use your measurements and selected specifications. Calculation scope.