Skip to content
BestCalculators
Free online calculators and converters

Home & Construction

Tile Calculator: Tiles, Boxes and Grout

Work out how many tiles and boxes a floor or wall needs, including cuts and breakage. Enter the area and the tile size and get the order quantity.

ft
ft
in

The face size printed on the box, not including the grout joint.

in
%

10% for a straight layout, 15% for diagonal or herringbone, 20% for a room with many cuts.

Printed on the box. Leave as is if you do not know it yet.

$

Tiles to order

132tiles

Covering 120 ft² with 10% allowed for cuts and breakage.

Area to cover
120ft²
Boxes to buy
14boxes
Spare tiles in the last box
8tiles

Keep them. A matching replacement is hard to find years later.

Estimated tile cost
$490

How to use this calculator

  1. Measure the room and enter the Area length and Area width in feet.
  2. Enter the face size of the tile in inches into Tile length and Tile width, leaving out the grout joint.
  3. Select a Waste allowance percentage based on your layout pattern, such as 10% for straight or 15% for diagonal.
  4. Enter the number of Tiles per box and the Price per box if you want to calculate total boxes and cost.
  5. Review the final number of tiles, boxes, and spare extras needed to complete the job.

How the Tile Calculator Works

When you use a tile calculator, you are solving a basic geometry puzzle that involves converting square feet into individual pieces of ceramic, porcelain, or stone. The process starts by multiplying your room length by your room width to find the total area in square feet. Next, the tool calculates the surface area of a single piece by multiplying the Tile length by the Tile width in inches, then dividing that product by 144 to convert inches into square feet. Finally, the total room area is divided by the individual tile coverage to find the base number of pieces required.

Behind the scenes, the tile flooring calculator quietly performs a crucial safety operation: rounding up. Because you cannot buy half a tile online or at the home center, the tool applies a ceiling function to every division step. If your room needs 401.2 pieces, the system rounds up to 402 before applying any waste factors. This prevents you from running short halfway through setting a kitchen floor or a bathroom shower wall.

Accounting for Cuts and Breakage

Every professional installer knows that how many tiles do i need is never answered by the bare floor area alone. Cutting tiles to fit around corners, door frames, and plumbing fixtures creates offcuts that often cannot be reused. Furthermore, chipping during wet-saw cutting or accidental drops will ruin a small percentage of your inventory. This is why the waste allowance percentage is the most critical variable you will enter.

  • 10% waste allowance is the standard baseline for a simple grid layout in a square or rectangular room.
  • 15% waste allowance covers diagonal installations, herringbone patterns, and rooms with multiple corners or obstructions.
  • 20% waste allowance accommodates complex chevron patterns, intricate mosaic sheets, or extremely small spaces with high cut ratios.

Translating Tile Counts into Boxes and Costs

Buying building materials requires bridging the gap between individual units and factory packaging. Manufacturers pack tiles into heavy corrugated cardboard boxes to protect them during transit. When you input the number of tiles per box, the floor tile calculator divides your total required inventory by that box count and rounds up once again. You cannot purchase 3.2 boxes of porcelain; you must buy 4 full boxes, which inevitably leaves you with a handful of spare pieces.

The tile square footage calculator tracks these leftover units explicitly, showing you exactly how many spare tiles remain in your final box. By multiplying the total box count by your price per box, the system generates an estimated material cost. Keep in mind that this financial figure covers only the ceramic or stone products. It excludes setting materials like thin-set mortar, cement backer board, grout, trim pieces, and rented wet-saw equipment.

Layout Patterns and Waste Comparison

Layout PatternRecommended Waste %Cut Complexity
Straight Grid10%Low
Diagonal / Straight15%Moderate
Herringbone15% to 18%High
Complex Mosaic20%Very High

When planning a backsplash tile calculator project for a kitchen, remember that wall surfaces often feature more interruptions than open floors. Outlets, window frames, light switches, and range hoods force continuous cuts along every edge. Even though a kitchen backsplash spans a smaller total square footage than a living room floor, the high frequency of cuts means you should rarely drop below a 15% waste allowance.

The formula

coverage per tile = tile length × tile width ÷ 144tiles = area × (1 + waste) ÷ coverage per tile, rounded upboxes = tiles ÷ tiles per box, rounded up

Frequently asked questions

Should I include the grout lines when measuring my tiles?

No, you should always use the face size printed on the manufacturer's box, which excludes the grout joint. Grout spacing is designed to be filled during installation and does not reduce the actual surface area of the tile itself. Measuring without grout joints ensures your calculation retains a safe margin for error.

Why does the result show extra tiles left over in the final box?

Tiles are sold in sealed factory boxes rather than as individual loose pieces. Because your total room requirement will almost never land on an exact multiple of the box count, the system rounds up to the nearest whole box. This naturally results in a few spare units remaining after the job is finished.

What waste percentage should I choose for a herringbone pattern?

You should select a waste allowance of at least 15% to 18% for any herringbone or chevron layout. Cutting the 45-degree angles required at the perimeter walls generates significantly more offcut waste than a traditional straight grid. Choosing a higher percentage prevents you from running out of material near the end of the installation.

Does this tool calculate the amount of mortar and grout I need?

No, this tool focuses strictly on calculating the number of tiles, boxes, and direct material costs. Mortar, cement board, spacers, and grout depend heavily on subfloor conditions, trowel size, and joint width. You will need to consult separate formulas or product coverage charts on mortar bags for those installation supplies.

When should I ignore these results and ask a professional?

You should consult a professional tile setter if your room features extreme structural irregularities, non-square walls, or curved architectural features. Standard mathematical tools assume flat rectangular planes and cannot anticipate complex custom layouts. An experienced installer should perform an on-site physical measurement for high-end natural stone or large-format slabs.

Last reviewed . Results are for general guidance and are not professional advice.