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Underlayment Calculator

Estimate underlayment rolls or sheets from floor area, product coverage, overlap, and waste.

Reviewed
2026-09-05
Units
US + metric

Calculated result / live

2 packages

Order 2 packages for 110.0 ft² of planned coverage; verify the selected product's package yield.

100.0 ft² area, 100.0 ft² per package, and 10% waste. The package coverage is an editable planning assumption.

Input panel

Project measurements

Secondary quantities
Measured area100.0 ft²
Planned coverage110.0 ft²
Package coverage100.0 ft²
Packages to order2

Calculation trace

Formula with your numbers

100.0 ft² × (1 + 10 ÷ 100) = 110.0 ft² ÷ 100.0 ft²/package = 2 packages

2 packages
01

What this underlayment calculator calculates

A 300 ft² floor with 10% overlap and waste needs 330 ft² of planned underlayment coverage.

Formula

Floor area × (1 + overlap and waste percent) ÷ product coverage = packages, rounded up.

Worked example

If a roll covers 100 ft² after overlap, 330 planned ft² requires 4 rolls.

Ordering decision

Follow the product's seam, perimeter, vapor-barrier, and subfloor instructions.

The page cites the applicable Uzi Tools reference table beside the calculator. Product labels, current editions, local code, and a licensed professional govern structural, electrical, and life-safety work.

02

How to use it

  1. Enter the measured dimensions and keep the displayed units beside each field.
  2. Review the floor underlayment rolls or sheets result and the substituted formula before ordering.
  3. Adjust waste for the layout, cut pattern, product package, and site conditions.
  4. Copy or print the material list, then verify the cited product data and local requirements.
03

Floor underlayment rolls or sheets

Use this underlayment calculator to convert floor area into rolls or sheets after overlap and waste. Product width and coverage belong in the input, not in a generic tile assumption.

04

Limits and professional review

Measurements, product yield, waste, moisture, and site conditions can change the order quantity. Local code and a licensed professional govern structural and electrical work.

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Related calculations

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Questions specific to this estimate