How this calculator works
It finds your room area, adds 5% for overlap and trimming, then divides by the square footage each roll of underlayment covers.
Worked example — a 12 ft × 10 ft room, 100 sq ft per roll:
120 sq ft × 1.05 = 126 ÷ 100 = 2 rolls.
120 sq ft × 1.05 = 126 ÷ 100 = 2 rolls.
Match it to your floor
Laminate, vinyl and hardwood each call for a specific underlayment. Some click floors come with padding pre-attached — check before buying separate rolls.
Frequently asked questions
How much underlayment do I need?
About the same as your floor area plus a small overlap allowance — divide by the roll’s coverage.
Do I need underlayment under vinyl plank?
Only if the planks don’t already have an attached pad — and never double up.