Tile Calculator
Calculate floor and wall tile square footage, exact individual tile counts, full retail boxes, 50 lb thin-set mortar bags, and layout waste allowances.
Calculation Results
The net flat square footage of floor or wall surface to tile.
Total square footage of tile required including layout cutting scrap.
Coverage of a single tile including the surrounding grout joint.
Total individual tiles needed to complete the room with waste margin.
Full retail cartons rounded up to the nearest unbroken box.
Standard 50 lb bags of modified thin-set mortar (assumes ~50 sq ft coverage with a 1/4"x3/8" square notch trowel).
Total tile purchase cost based on the full box quantity and price per square foot.
How This Calculator Works
Plan your bathroom, kitchen, or patio tiling project in 4 simple steps:
- Measure the Surface: Enter the length and width of the floor or wall area in feet. For rooms with nooks, calculate sections individually and sum the square footage.
- Input Tile & Grout Dimensions: Enter your tile length and width in inches, and choose your grout joint spacing (1/8-inch is standard for most ceramic and pressed porcelain).
- Select Pattern Waste: Choose 10% for straight grid, 12% for subway brick bond, 15% for diagonal, or 20% for herringbone.
- Review Material Takeoff: Order the required full boxes, individual replacement tiles, and 50 lb thin-set mortar bags.
Formula & Calculations
Tile estimates require calculating exact surface square footage, adjusting for grout joints, and rounding up to whole manufacturer packaging boxes:
1. Net Area & Layout Scrap Factor
Net Area (sq ft) = Room Length × Room Width
Gross Area = Net Area × (1 + Waste% / 100)
- Straight Grid (Stack / Jack-on-Jack): 10% waste for perimeter wall cuts.
- Offset / Subway Brick Bond (1/3 or 1/2 step): 12% waste.
- Diagonal (45° Angle): 15% waste due to triangular border off-cuts.
- Herringbone Pattern: 20% waste because 45-degree corner angles generate significant unusable scrap.
2. Individual Tile and Box Counts
Single Tile Area (sq ft) = ((Length + Grout) / 12) × ((Width + Grout) / 12)
Tiles Needed = ceil(Gross Area / Single Tile Area)
Boxes to Order = ceil(Gross Area / Box Sq Ft)
3. Thin-Set Mortar Rule of Thumb
A standard 50 lb bag of polymer-modified dry-set mortar covers approximately 45 to 55 sq ft when applied with a 1/4" × 3/8" square-notch trowel for medium-to-large format tiles.
Step-by-Step Calculation Examples
Master Bathroom Floor (10ft x 12ft, 12x12 Tiles)
Tiling 120 sq ft with 12x12 porcelain tiles, 1/8" grout joints, 10% waste, and 15 sq ft/box at $4.50/sq ft.
- length: 12
- width: 10
- tile_length: 12
- tile_width: 12
- grout_joint: 0.125
- waste: 10
- box_sqft: 15
- cost_per_sqft: 4.5
- net_area: 120.0 sq ft
- gross_area: 132.0 sq ft
- single_tile_sqft: 1.021 sq ft
- tiles_needed: 130
- boxes_needed: 9
- thinset_bags: 3
- estimated_tile_cost: $607.50
Frequently Asked Questions
How many boxes of tile do I need for a 10x10 room?
A 10x10 room is 100 square feet. Adding a 10% waste allowance brings the total required to 110 square feet. If your tile comes packed in 15 sq ft boxes, you will need 8 full boxes (110 / 15 = 7.33, rounded up to 8 boxes, giving 120 sq ft).
Why do I need 15% to 20% extra tile for herringbone layouts?
Herringbone patterns require every single perimeter tile to be cut at a 45-degree angle. Because the cut scrap piece on one side rarely fits the mirror angle on the other wall without exposing a factory edge in the middle of a grout joint, triangular scrap waste is dramatically higher than straight running bonds.
How much thin-set mortar do I need per square foot?
As a rule of thumb, one 50 lb bag of modified thin-set mortar covers roughly 45 to 50 sq ft using a 1/4" x 3/8" square-notch trowel (standard for 12x12 to 12x24 tiles). For smaller mosaic tiles using a 3/16" V-notch trowel, coverage increases to 80-90 sq ft per bag.
Should I deduct doors and windows for shower and bathroom walls?
Yes. For shower walls, calculate each wall panel (Length x Height), sum them together, and subtract any window openings (typically 12 to 15 sq ft) or built-in shower niches before applying the 10% cutting waste factor.
Why should I save extra boxes of tile after installation?
Always save at least one full box of extra tile. Ceramic and porcelain tiles are manufactured in dye lots and run numbers. If a tile cracks later or you need plumbing repairs behind a wall, purchasing the exact same color, shade, and caliber years later is nearly impossible.
What size grout joint should I use for porcelain vs ceramic tile?
Rectified porcelain tiles (mechanically cut with precise 90-degree edges) can be installed with narrow 1/16-inch or 1/8-inch joints. Non-rectified ceramic or handmade terracotta tiles have natural dimensional variance and require wider 3/16-inch or 1/4-inch joints to conceal uneven edges.