Laminate Flooring Calculator
Laminate-specific estimate: boxes of planks, underlayment rolls and vapor barrier, quarter round, transitions, expansion gap and last-row width.
Your estimate
10 boxes
Boxes of laminate (incl. 10% waste)
- Floor area
- 168 sq ft
- Coverage purchased
- 199 sq ft
- Underlayment
- 2 rolls
- Rows across the room
- 18 full + 2 ripped to 4.13 in
- Quarter round
- 49 ft (7 pcs)
- The last row would only be 0.75 in wide. Rip the first and last rows to about 4.13 in each so both edges look even and lock properly.
Show the math
- Area = 14 ft × 12 ft = 168 sq ft
- × (1 + 10%) = 184.8 sq ft ÷ 19.9 sq ft per box → 10 boxes
- Rows: (width − 2 × 3/8 in gap) ÷ 7.5 in = 19.1 → 18 full + 2 ripped to 4.13 in
- Quarter round = perimeter − 1 × 3 ft = 49 ft
Shopping list & cost
| Item | Spec | Qty | Cost |
|---|---|---|---|
| Laminate flooring | 19.9 sq ft per box | 10 boxes | — |
| Foam underlayment | 100 sq ft rolls, butted not overlapped | 2 rolls | — |
| Quarter round / shoe molding | 8 ft pieces, minus doorways | 7 pcs (49 ft) | — |
| T-molding / transition strip | one per doorway | 1 | — |
| Spacers, tapping block, pull bar | 3/8 in expansion gap | 1 kit | — |
Prices are what you enter under Advanced options. Estimates only — check stock and pricing with your supplier.
Quick answer A 14 × 12 ft room in laminate at 19.9 sq ft per box needs 10 boxes with 10% waste, plus 2 rolls of underlayment, 49 ft of quarter round and a ⅜ in expansion gap at every wall. With 7.5 in planks the rows across the room work out as 18 full + 2 ripped to 4.13 in, so a sliver last row is avoided. A 4.2 × 3.6 m room needs 9 boxes at 1.97 m² per pack.
Method & assumptions
Boxes = Length × Width × (1 + waste %) ÷ Coverage per box Rows = (Width − 2 × gap) ÷ Plank face width If the last row < ⅓ plank: rip first and last rows to (last + plank) ÷ 2 Underlayment rolls = Area ÷ roll coverage Quarter round = Perimeter − 3 ft per doorway
- Expansion gap
- space at every wall and fixed object for the floating floor to move; ¼–⅜ in (6–10 mm)
- Face width
- visible width of the plank, without the tongue
- Vapor barrier
- 6-mil polyethylene over concrete slabs
Assumptions & limits
- Floor area is taken wall to wall; the expansion gap is too small to reduce the box count.
- Foam underlayment is butted, not overlapped (100 sq ft / 10 m² rolls typical); poly is overlapped 8 in and run up the wall, adding about 10%.
- Quarter round is sold in 8 ft (2.4 m) lengths; 10% added for miters.
- Many brands limit unbroken runs to about 30–50 ft; longer rooms need a T-molding expansion break — check your guide.
Rounding: purchase quantities are always rounded up to whole units as sold. See our methodology.
Diagram
How to use this calculator
- Measure the room length (the direction the planks will run — usually toward the main window) and the width.
- Enter the coverage per box from the carton and keep 10% waste (12–15% for many doorways or a diagonal layout).
- Enter the plank face width and the expansion gap from the installation guide; the calculator checks the width of the last row.
- Pick the underlayment. Over concrete, use a 6-mil poly vapor barrier under foam, or a combo underlay — unless the planks have an attached pad that the maker says replaces it.
- Count doorways for T-moldings or transitions and use the quarter-round line for the expansion gap cover.
Worked examples
Imperial: 16 × 13 ft living room, 7.5 in planks, 19.9 sq ft/box
- 208 sq ft × 1.10 = 228.8 ÷ 19.9 = 11.5 → 12 boxes
- Rows: (156 − 0.75) ÷ 7.5 = 20.7 → 20 full + a 5.25 in last row (fine)
- Underlayment: 3 × 100 sq ft rolls; quarter round 55 ft
Metric: 5 × 3.2 m bedroom, 192 mm planks, 1.97 m²/pack
- 16 m² × 1.10 = 17.6 ÷ 1.97 = 8.9 → 9 packs
- Rows: (3,200 − 20) ÷ 192 = 16.6 → 16 full + 108 mm last row
In depth: laminate flooring planning notes
What makes laminate different from other floors
Laminate is a floating floor: the planks click together into one sheet that rests on an underlayment and is never fastened to the subfloor. As humidity changes, that whole sheet expands and contracts, which is why the manufacturer specifies an expansion gap — usually ¼–⅜ in — at every wall, pipe, door frame and cabinet. Pin it in place with a heavy island, nail through it, or butt it tight to a wall and it will buckle in summer. Very long runs move more, so many brands require a T-molding expansion break once a run exceeds roughly 30–50 ft, and at most doorways.
Because the core is high-density fiberboard, laminate also cares about moisture from below. Over a concrete slab, you need a vapor barrier — 6-mil polyethylene overlapped about 8 in and taped, or an underlayment with a built-in film. Many planks now come with an attached pad; some makers say that replaces separate underlayment, others still want poly over concrete. Read your brand's guide before you buy rolls. If your project is vinyl plank or hardwood instead, the general flooring calculator is the better fit.
Rows, last-row width and the shopping list
Planks normally run the length of the room, toward the main source of light, so the joints are less visible. Divide the room width (less the gap at both walls) by the plank's face width and you know how many rows you will lay — and how wide the last row will be. A last row only an inch or two wide is hard to lock and looks like a mistake, so the standard fix is to rip the first row narrower so the first and last rows match. The calculator flags that and gives the balanced width.
Boxes are the area plus about 10% waste divided by the carton coverage; offcuts from the end of each row usually start the next one, which keeps waste low on straight lays. Add underlayment rolls (butted, not overlapped), quarter round or shoe molding to cover the gap where baseboard stays in place, a T-molding or reducer at each doorway, and a spacer and tapping-block kit. Let the boxes acclimate flat in the room for the time the maker specifies — often 48 hours — and mix planks from several boxes as you go to avoid patches of one shade.
Reference table
| Situation | Waste |
|---|---|
| Simple rectangle, straight lay | 8–10% |
| Several doorways, closets or a hallway | 10–12% |
| Diagonal layout | 15% |
| Herringbone laminate | 15–20% |
| Keep for repairs | 1 unopened box |
Key facts
- Expansion gap
- ¼–⅜ in (6–10 mm) at walls, pipes and door frames
- Acclimation
- typically 48 hours in the room, boxes flat
- Over concrete
- 6-mil poly vapor barrier unless built in
- Last row
- at least ⅓ plank or about 2 in wide
Tips & common mistakes
- Stagger end joints at least 8–12 in between rows and avoid "H" patterns; start each row with the offcut from the last.
- Undercut door casings with a jamb saw so planks slide under rather than being scribed around.
- Never nail or glue a floating laminate floor to the subfloor, and don't pin quarter round into the laminate — nail it to the baseboard.
- Check the subfloor is flat to the brand's spec (often 3/16 in in 10 ft) before you buy underlayment.
Frequently asked questions
How many boxes of laminate flooring do I need?
Room area × 1.10 ÷ the coverage per box. A 14 × 12 ft room (168 sq ft) with 19.9 sq ft boxes needs 184.8 ÷ 19.9 = 9.3 → 10 boxes.
How much expansion gap does laminate need?
Usually ¼–⅜ in (6–10 mm) around the whole perimeter and at fixed objects like pipes and door frames. Large rooms may need more — follow your brand's installation guide.
Do I need underlayment for laminate?
Yes, unless the planks have an attached pad. Over concrete you also need a moisture barrier: 6-mil poly or an underlayment with a built-in vapor barrier.
How much extra laminate should I buy?
10% for most rooms, 15% for diagonal layouts. Keep one unopened box for future repairs — matching a discontinued line is very hard.
What if the last row of laminate is too narrow?
Divide the shortfall: rip the first row so the first and last rows are equal, each at least a third of a plank (or about 2 in). The calculator does this for you.
Is laminate the same as vinyl plank?
No. Laminate has a fiberboard core and is sensitive to standing water; vinyl plank (LVP) is plastic-based and more water-resistant. For vinyl plank or hardwood, use the general flooring calculator.
Sources
- Pergo – Installation Essentials Guide (PDF) — accessed : “Add 10% to your square footage for standard installations.”
- Pergo – Project planner checklist (PDF) — accessed : “Add a 10% waste factor to your total square footage … square feet × 1.10 = total required”
- North American Laminate Flooring Association (NALFA) – installation — general reference — not cited for a specific figure
- Mohawk – laminate installation guide — general reference — not cited for a specific figure
Default values (yields, coverage rates and densities) are typical figures from manufacturer literature. Always check the label on the product you buy.
Related calculators
- Flooring CalculatorCalculate boxes of vinyl plank, hardwood or engineered flooring, including a 12×12 room, with layout waste, underlay and baseboard.
- Baseboard CalculatorLinear feet of baseboard (skirting) for a room minus door openings, converted to 8, 12, 14 or 16 ft pieces with waste, nails and caulk.
- Carpet CalculatorHow much carpet do you need? Square yards cut from 12 or 15 ft rolls, number of seams, pad, tack strip and seam tape for any room.
Learn more in our guides
Method, waste and worked examples: Flooring area: waste, boxes and roll width.
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DIYCalcLab. “Laminate Flooring Calculator.” Oct 19, 2026. https://diycalclab.com/flooring/laminate-flooring-calculator/
Estimates only. Verify quantities with your supplier and local building codes. For structural, electrical or safety-critical work, consult a licensed professional. Full disclaimer.