Flooring calculator

Carpet calculator

Carpet coverage and whole-roll quantity using the selected product's net coverage.

Calculator result and formula

Carpet rolls or cuts to order: 2 rolls

Formula: L × W × (1 + waste) ÷ stated coverage

Formula ID: FLOOR-CARPET-001 · Version 1.0.0 · Published · Last reviewed Aug 26, 2026.

Inputs

  • Floor length: Finished carpet area length Default: 18.
  • Floor width: Finished carpet area width Default: 14.
  • Roll coverage: Net coverage of the selected carpet roll or cut Default: 180.
  • Waste factor: Allowance for seams, pattern matching and cuts Default: 10.

How this calculator works

This calculator divides finished carpet area plus seam and cut allowance by the selected roll or cut's stated net coverage.

  1. Measure the finished room dimensions.
  2. Enter usable coverage for the selected carpet roll or quoted cut.
  3. Increase allowance when seams, directional pile or pattern matching require it.

Worked example: Example: an 18 ft × 14 ft room with 10% allowance and 180 ft² roll coverage rounds to 2 rolls or cuts.

Assumptions and limitations

  • Coverage should use the selected manufacturer's product label or quoted net coverage.
  • Waste is added before whole-unit purchase rounding.
  • Complex layouts, seams or patterns can require a higher documented allowance.

Common mistakes to avoid

  • Confirm the measurement basis and units before using the result.
  • Keep waste or allowance visible and adjust it for the actual job conditions.
  • Confirm supplier packaging, delivery increments, specifications, and final site requirements before ordering.

Calculator disclaimer

This planning calculator does not determine structural design, code compliance, installation requirements, or guaranteed pricing. Confirm final requirements with the appropriate responsible professional, authority, manufacturer, and supplier.

Formula review and sources

Internal QA complete · independent external review pending · 1 source reference.

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