Flooring Calculator (Square Feet and Boxes)
Enter the room size, a waste allowance and the square feet per carton printed on the box or product page.
How it works
Order area = (length × width + extra − left out) × (1 + allowance). Cartons = order area ÷ coverage per carton, rounded up. This is the method Mohawk Home gives: (room length × room width) × 1.10 ÷ sq ft per carton, then round up. 1 sq ft = 0.09290304 m² (NIST).
Worked example: Mohawk Home: a 12 × 15 ft room is 180 sq ft. With 10%: 198 sq ft. At 17.3 sq ft per carton, 198 ÷ 17.3 = 11.4, so 12 cartons.
Assumptions
- Allowance defaults: 10% for straight and 15% for diagonal installs, as Mohawk's SolidTech Plus instructions recommend. Shaw's solid hardwood guide calls for 5-10% depending on layout, more for diagonal, herringbone or bordered floors. Use your product's figure.
- Coverage default 17.3 sq ft per carton is Mohawk's example product. Cartons vary widely; enter the number on your box.
- Underlayment, transitions, trim and moldings are not included.
- This is a quantity estimate only. Follow the product's installation instructions and check local codes.
Frequently asked questions
How many boxes of flooring do I need for a 12 × 15 room?
Mohawk Home's example: 12 × 15 = 180 sq ft × 1.10 = 198 sq ft ÷ 17.3 sq ft per carton = 11.4, so 12 cartons.
How much extra flooring should I buy?
Mohawk's SolidTech Plus instructions say to add 10% for standard installations and 15% for diagonal ones. Shaw's hardwood guide says 5-10% depending on layout.
Do I subtract cabinets and islands?
Leave out areas under permanent fixtures that will not get flooring. Mohawk's rigid vinyl instructions say permanent cabinets and islands are installed first and the floor goes around them.
Related calculators
Sources
Formulas and reference values are from these sources. Page content last updated 2026-10-19.
- Mohawk Home: General product questions (cartons = area × 1.10 ÷ sq ft per carton, worked example)
- Mohawk SolidTech Plus installation instructions (add 10% for standard, 15% for diagonal installs)
- Shaw solid hardwood installation and care guide (5-10% waste factor, depending on layout)
- NIST Guide to the SI (SP 811), Appendix B.9: conversion factors (foot = 0.3048 m, ton, pound)