Solve backwards
How much floor will my rolls of underlayment cover?
- 5 rollsThe example worked below
- Laminate/Vinyl Plank Floor Underlayment Roll CalculatorEvery figure is its own
You have
How much floor underlayment?
Worked by the Laminate/Vinyl Plank Floor Underlayment Roll Calculator at the settings below.
The settings it uses
- Roll Coverage Area
- 100 sq ft
What it will do
500 sq ft of floor
46.5 m²
One floor. Enough for a floor about 22.4 × 22.4 ft.
Or several. About 1 floor of the size the Laminate/Vinyl Plank Floor Underlayment Roll Calculator opens on: a floor about 20.7 × 20.7 ft.
Check it forwards
- Floor Area
- 500 sq ft
- It asks for
- 5 rolls
- You have
- 5 rolls
The Laminate/Vinyl Plank Floor Underlayment Roll Calculator asks for 5 rolls at that size, and 6 rolls one step larger.
If you had more, or less
Around your amount
Each worked by the Laminate/Vinyl Plank Floor Underlayment Roll Calculator at the same settings.
Half
3 rolls
300 sq ft
a floor about 17.3 × 17.3 ft
Yours
5 rolls
500 sq ft
a floor about 22.4 × 22.4 ft
Half as much again
8 rolls
800 sq ft
a floor about 28.3 × 28.3 ft
Double
10 rolls
1,000 sq ft
a floor about 32 × 32 ft
Common amounts
What each amount of floor underlayment covers
The sizes it is usually sold in, each worked by the Laminate/Vinyl Plank Floor Underlayment Roll Calculator at the settings above.
| You have | It covers | As one floor | Average floors |
|---|---|---|---|
| 1 roll | 100 sq ft(9.29 m²) | a floor about 10 × 10 ft | under 1 |
| 2 rolls | 200 sq ft(18.6 m²) | a floor about 14.1 × 14.1 ft | under 1 |
| 5 rolls | 500 sq ft(46.5 m²) | a floor about 22.4 × 22.4 ft | 1 |
| 10 rolls | 1,000 sq ft(92.9 m²) | a floor about 32 × 32 ft | 2 |
Check the back of the board first
A great many laminate and click-vinyl boards ship with a pad bonded to the back. Adding a separate underlayment under one of those stacks two cushions under a click joint: the joint over-flexes, the tongue works loose and the seams gap, and most makers void the warranty for it. The area here matters only once the board says you need a roll.
The roll's stated coverage, not its size
The calculator opens at 9.3 m² a roll, 100 square feet, and takes your product's stated coverage in its place, because rolls are sold by the area they cover rather than a fixed width. The calculator takes no lap off — foam rolls are commonly butted edge to edge and taped — so the answer is the floor the stated coverage buys.
Over concrete, the vapour rating decides
On a slab on or below grade, what governs is the underlayment's vapour rating — a 6-mil polyethylene film or a combination product with an integral barrier, lapped, taped and turned up the wall. A plain foam roll of identical coverage provides none of it; the slab wicks, the planks cup, and it reads afterwards as a flooring fault.
How the answer is worked
Nothing here is a second formula. The Laminate/Vinyl Plank Floor Underlayment Roll Calculator runs forwards — a size in, a quantity out — and this page grows its own starting floor in proportion until the quantity it asks for is what you have. Where it rounds up to whole containers, the answer is the largest size before the next one would be needed.
Where the calculator adds an allowance for cuts or breakage when you order, the same allowance comes off here, because it is the same calculator: a stack you already own finishes less than its face value. Where it adds none, neither does this page — the settings beside the answer say which.
Laminate/Vinyl Plank Floor Underlayment Roll Calculator
runs it forwardsCalculate how many underlayment rolls are needed beneath a laminate or vinyl plank floor.
Work out what to buy insteadSolve backwards
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Solve backwards
Start from what is already in the yard
Paint, sheets, rolls, bags and pieces, each read the other way by the calculator that orders it.
The calculator's own figures
Nothing is estimated twice: the page runs the same calculator you would order with.
The largest size that fits
Where a calculator rounds up to whole containers, the answer stops before the next one.
Both unit systems
Gallons and litres, square feet and square metres, side by side.
Frequently asked questions
- How much floor does 5 rolls of floor underlayment cover?
- At the Laminate/Vinyl Plank Floor Underlayment Roll Calculator's own settings, 500 sq ft (46.5 m²) — a floor about 22.4 × 22.4 ft. That is about 1 floor of the size the calculator opens on: a floor about 20.7 × 20.7 ft. Every figure follows the settings, which you can change in the calculator.
- How many square feet does a roll of laminate underlayment cover?
- It depends on the product — rolls are sold by stated coverage, commonly 100 square feet (9.3 m²), with larger rolls common too. The calculator opens at 100 and takes your roll's figure; divide the floor area by that coverage and round up to whole rolls.
- Do I need underlayment if my vinyl plank has a pad attached?
- Usually not, and usually you must not. A second cushion under a board with an attached pad lets the click joint flex until it fails, and most manufacturers void the warranty. A thin vapour film over concrete may still be required — the board's installation instructions say which.
- Can underlayment level an uneven floor?
- No. Underlayment bridges small texture, it does not fill dips. Board makers commonly ask for flatness around 3 mm under a 2 m straightedge (about an eighth of an inch over 6.5 feet); grind the high spots and fill the low ones first, or the plank rocks and the joint breaks.