Floating Floor Underlayment Calculator
Rolls of underlayment for a floating floor.
Enter your values
ⓘ Live results
Results
- Rolls needed
- 3
- Room area
- 192 sq ft
- Area with waste
- 201.6 sq ft
- Total coverage bought
- 300 sq ft
Quick answer
Underlayment quantity is room area plus waste, divided by the coverage of one roll.
rolls = ceil((area x (1 + waste%)) / coverage per roll)
How to use the Floating Floor Underlayment Calculator
- 1Measure the room area.
- 2Check the roll coverage on the underlayment packaging.
- 3Add 5-10% waste for seams and trimming around the edges.
Worked example
Using the values the calculator loads with:
Inputs
- Room length16 ft
- Room width12 ft
- Coverage per roll100 sq ft
- Waste allowance5 %
Results
- Rolls needed3
- Room area192 sq ft
- Area with waste201.6 sq ft
- Total coverage bought300 sq ft
Frequently asked questions
Do I always need underlayment?
Most floating laminate and vinyl floors require it for sound and moisture control unless the plank already has an attached pad.
Can I overlap seams?
No, most underlayments are taped edge to edge, not overlapped, to keep the floor flat.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.