Flooring Calculator
Estimate flooring boxes and square footage needed.
Results update as you type.
How it works
A flooring calculator tells you how many boxes of flooring to buy for a room and the total square footage to order, starting from the room's dimensions and the coverage printed on each box. It multiplies length by width for the floor area, adds a waste allowance, then divides by the per-box coverage and rounds up to whole boxes. The waste step is the part people skip and regret: laying planks or tiles wastes material at the end of every row, where the offcut is often too short to begin the next row, and more is lost to cuts around doorways, hearths and irregular walls, plus the odd damaged or off-color board pulled from the run. Ordering only the exact area almost always leaves you short, and a later top-up may come from a different dye lot or batch that does not match. The built-in ten percent allowance suits a simple rectangular room laid straight; diagonal or herringbone patterns and rooms with many jogs and alcoves waste more and deserve a higher margin. Because coverage varies enormously between products — wide planks, narrow strips, large tiles — entering the figure from the box you are actually buying is what keeps the count right. Homeowners, installers and renovators use it to price a floor and buy enough the first time, ideally with a spare box set aside for future repairs from the same batch.
Area = length × width; total = area × (1 + waste%); boxes = ⌈total ÷ coverage per box⌉
Room length times width gives the floor area in square feet. Multiplying by one plus the waste fraction adds an allowance for the planks lost to end cuts, the offcut at the end of each row that often cannot start the next, and boards culled for defects. Dividing that adjusted area by the square footage one box covers — printed on the carton — gives how many boxes are required, and rounding up buys whole boxes since flooring is not sold loose. Entering the coverage from the exact product matters because box coverage varies widely between plank sizes and flooring types.
Source:Standard construction estimation (area method)
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter room length and room width.
- 2
Adjust the options
Adjust coverage per box and waste allowance if they apply — sensible defaults are already set.
- 3
Read your result
Boxes to buy updates instantly as you type — no button to press.
Frequently asked questions
How much flooring waste should I allow?
Ten percent is the usual starting point for a simple rectangular room laid in straight rows, and it is built into this calculator. Diagonal and herringbone layouts, rooms with many corners, alcoves or angled walls, and long narrow planks all waste more, so step up to 15 percent or higher for those. The margin covers end-of-row offcuts, cuts around obstacles, and boards culled for damage or color. It is cheaper to buy a spare box than to reorder mismatched stock.
Why does box coverage vary so much?
Because flooring comes in many plank and tile sizes and materials, each box holds a different total area. A carton of wide, long planks may cover 25 square feet, while narrow strips or small tiles cover less per box. The coverage is printed on every carton. Always enter that exact figure rather than a generic number, since using the wrong coverage is the biggest source of error in a flooring estimate.
Should I keep spare flooring after installing?
Yes. Set aside at least a spare box, or a few extra planks, from the same purchase and batch. Flooring color and finish shift subtly between production runs and dye lots, so a future repair using freshly bought stock can stand out against the original floor. Labeled spares stored flat and dry let you swap a damaged plank years later with a piece that matches the rest of the room exactly.
How do I measure a room for flooring?
For a rectangular room, multiply the length by the width to get the floor area in square feet. For an L-shaped or irregular room, divide it into rectangles, calculate each, and add them together. Measure into doorways and closets you intend to floor, and round dimensions up rather than down. Then let the waste allowance handle the cuts, so a slightly generous measurement is safer than a tight one.
Does this calculator include underlayment?
No. It estimates only the flooring boxes and area; underlayment, transition strips, trim and adhesive are separate items you buy to suit the product and subfloor. Underlayment is usually sold by the roll with its own coverage, so calculate it from the same room area. Check whether your flooring has an attached pad, since that can eliminate the need for a separate underlayment layer beneath it.