Laminate Flooring Calculator
Figuring out how many boxes of laminate flooring you need is simple math — but forget the waste allowance and you'll be making a second trip to the store. Our free laminate flooring calculator turns your room's length and width into square feet, boxes to buy, underlayment needed, and an estimated material cost, with the waste factor built in.
Enter your numbers
Your results
| Room area | — |
| Underlayment needed | — |
| Estimated cost | — |
Estimate: boxes round up to whole boxes and include the waste allowance. Actual needs vary with plank size, room shape, and your box coverage. Underlayment is sold in rolls — round up to whole rolls at the store.
How to use this calculator
Measure your room's length and width in feet and enter them above — use the longest dimensions of an L-shaped room and we'll talk about irregular shapes below. Pick your plank layout: Straight auto-fills a 7% waste allowance, Diagonal auto-fills 12% for the extra angled cut-offs, and Custom lets you keep whatever percentage you type.
Enter the coverage per box from your laminate's label (about 20 sq ft is typical, but it varies by product). Optionally add the price per box for an estimated material cost. Results update instantly as you type.
How it works
Room area is simply area = length (ft) × width (ft). The material you must buy adds the waste allowance: material = area × (1 + waste % ÷ 100). Boxes then round up to the nearest whole box: boxes = ceil(material ÷ box coverage), because stores sell whole boxes.
Underlayment equals the room area with no waste factor, since it comes in rolls you cut to fit with little loss. If you enter a price per box, the calculator multiplies boxes × price per box and labels the result an estimate — it doesn't include underlayment, trim, or installation labor.
For L-shaped or irregular rooms, split the floor into rectangles, calculate each separately, and add the box counts together.
Frequently asked questions
How much laminate flooring waste should I add?
Add about 7% waste for a straight plank layout and about 12% for a diagonal layout, which produces far more cut-offs. Bump the waste factor to 10–15% for rooms with lots of doorways, alcoves, or angled walls, or if you are installing your first floor. This calculator auto-fills the 7% and 12% defaults when you pick a layout, and you can type your own percentage.
How many boxes of laminate flooring do I need for 100 sq ft?
With the common 20 sq ft per box: 100 sq ft × 1.07 waste = 107 sq ft, then 107 ÷ 20 = 5.35, which rounds up to 6 boxes for a straight layout. A diagonal layout needs about 12% waste, which also lands on 6 boxes (112 ÷ 20 = 5.6, rounded up). Box coverage varies by product — typically 17 to 30 sq ft per box — so use the number printed on your box label for the most accurate count.
Do I need underlayment under laminate flooring?
In most cases, yes. Underlayment cushions the planks, smooths out minor subfloor imperfections, and cuts down on sound; many products also include a moisture barrier needed over concrete subfloors. Buy underlayment equal to your room area in square feet — this calculator shows that number automatically. Some laminate comes with attached underlayment, in which case you can skip buying it separately.
Can I install laminate flooring over old flooring?
Often yes, as long as the old surface is flat, dry, and stable — vinyl, tile, or an existing laminate layer are usually fine. Never install laminate over carpet, and repair any soft, damaged, or uneven spots in the subfloor first. Check the manufacturer's instructions, since some warranties require removing certain existing materials.
Is a diagonal laminate layout worth it?
It can make a small or oddly shaped room look larger and adds visual interest, but it costs more: plan on about 12% waste instead of 7% because every edge plank gets cut at an angle, and the job takes noticeably longer. If you are hiring an installer, diagonal layouts often carry a higher labor quote.