The calculator above tells you exactly how many tiles to buy, how much grout and thinset to order, and what the project will cost. Enter your room dimensions, pick your tile size, set your grout joint, and choose a layout pattern. This guide explains how every number in the output is calculated so you understand what you are ordering and why.
Table of Contents
- How to use this tile calculator
- How to measure your room
- Tile sizes and how to choose
- Waste factor by layout pattern
- Grout joint width and grout type
- How much thinset you need
- Cost by tile type and pattern
- Tips before you order
- Frequently Asked Questions
How to Use This Tile Calculator
Start by selecting your room shape at the top. The calculator supports four options.
Rectangle covers most single rooms. Enter length and width and the calculator multiplies them to get your floor area.
L-Shape handles rooms with a step-out section. Measure both rectangular portions separately and enter all four dimensions. The calculator adds the two areas together.
Two Rooms lets you combine a bathroom and a hallway, or any two separate tiled spaces, into one order so you can buy from a single lot.
Custom Area works when you already know your square footage. Type it directly and skip the dimension inputs.
Switch between feet and meters with the unit toggle. All outputs update immediately. After entering dimensions, pick your tile size from the presets or type custom dimensions. Set your grout joint with the slider. Choose your layout pattern. Then click Calculate.
How to Measure Your Room
Measure wall to wall at the widest point. Do not stop at cabinetry or fixtures. A vanity sits on top of the tile, not under it, so you tile the full floor area.
For walls such as shower surrounds, measure each wall separately. Length times height gives you the tiling area per wall. Add all four walls together. Subtract large openings like a shower niche or window, but do not subtract soap dishes or small recesses.
Use a tape measure rather than a laser for anything under 20 feet. Lasers bounce off glass and chrome at odd angles. Write measurements in feet and decimal fractions, not feet and inches. A room that is 9 feet 6 inches is 9.5 feet, not 9.6.
Tile Sizes and How to Choose
The calculator includes six common presets. You can also type any custom size.
The 12×12 inch tile is the most widely available size. It covers exactly 1 square foot per tile and is easy to verify by hand.
The 12×24 inch format is popular in bathrooms and hallways. It makes small spaces look larger when the long side runs the length of the room.
The 18×18 inch tile works well in open living areas. Fewer grout lines give the floor a cleaner look. This size requires a flat subfloor because tiles larger than 15 inches bridge low spots and crack at the edges.
The 24×24 inch format is common in kitchens and large entryways. It demands medium-bed mortar and back-buttering on every tile. Standard thinset alone does not provide enough adhesion for large-format tile.
Smaller tiles like 4×4 or 6×6 subway are common in wet areas and backsplashes. More grout lines mean more grout and more installation time per square foot.
Waste Factor by Layout Pattern
Every tile job wastes material. Tiles get cut at walls, around obstacles, and to fit angles. The waste factor adds a buffer so you do not run short.
Straight layout at 10% waste. Tiles run parallel to the walls. This is the fastest and most material-efficient pattern.
Diagonal at 15% waste. Tiles rotate 45 degrees. Every wall edge requires a diagonal cut. Those triangular offcuts cannot be reused. A 10×10 room in a diagonal pattern needs the same material as roughly an 11×11 room in a straight pattern.
Offset or brick pattern at 15% waste. Each row shifts by a set amount, usually 33% or 50% of the tile length. Cuts at both ends of each row drive the waste. This pattern is popular with rectangular subway tile.
Herringbone at 20% waste. Tiles alternate direction at 90 degrees. The angle cuts are the most complex of any standard pattern. Even experienced installers lose 18% to 22% of material on herringbone floors. This pattern also takes the most labor time.
Buy from a single production lot regardless of pattern. Tile color varies between manufacturing runs. If you run short and order a second batch, it will not match.
Grout Joint Width and Grout Type
The grout joint slider runs from 1/16 inch to 1 inch. Your choice affects how much grout you buy and which type you need.
For joints narrower than 1/8 inch, use unsanded grout. The fine texture flows into tight gaps without pinholes. Unsanded grout is also required for polished natural stone like marble because sand particles scratch the surface.
For joints 1/8 inch and wider, use sanded grout. The sand particles prevent shrinkage and cracking in wider gaps. Sanded grout handles foot traffic better. For joints 3/8 inch or wider, use a wide-joint mixture with a higher aggregate content.
For shower walls and wet areas with polished stone or glass tile, epoxy grout outperforms both options. It is waterproof, stain-resistant, and does not require sealing. The working time is short and cleanup requires a proprietary solution, so read the product instructions before mixing.
The grout estimate in the calculator is derived from a TCNA formula scaled by your joint width and tile size. For 12×12 tiles with a 1/4 inch joint, the estimate runs about 0.5 lbs per 10 square feet. Wider joints and smaller tiles increase that number. Verify against the coverage table on the specific product you buy.
Wait 24 to 48 hours after setting tile before grouting. Grouting over uncured thinset traps moisture and causes grout joints to crack.
How Much Thinset You Need
The calculator estimates thinset at roughly 4.5 lbs per square foot as a general baseline. Check this against the coverage rate on your specific thinset bag before purchasing.
Standard unmodified thinset works for interior ceramic tile on cement board. Use modified polymer-enriched thinset for porcelain, any tile larger than 15 inches, plywood substrates, and heated floors.
For tiles larger than 18 inches, installers typically use a 1/2 inch square-notch trowel. Smaller tiles use a 3/16 or 1/4 inch V-notch. The trowel notch size determines how much mortar sits under each tile, which changes your thinset consumption per square foot.
Back-buttering, spreading a thin layer of thinset directly on the back of each tile before setting, is required for large-format tile. It increases thinset use by 15% to 25%. Add that to your estimate if your tile is 18 inches or larger.
Cost by Tile Type and Pattern
The cost bar under the calculator takes your material cost and install cost per square foot and multiplies against the waste-adjusted area. Enter them separately so you see where your budget splits.
2025 installed cost ranges by tile type:
- Ceramic tile: $7 to $25 per square foot installed. Material runs $1.50 to $5 per square foot. The most budget-friendly option for low to moderate traffic areas.
- Porcelain tile: $10 to $30 per square foot installed. Material costs $3 to $10 per square foot. Denser than ceramic, absorbs less water, and handles heavy traffic.
- Natural stone (marble, slate, travertine): $15 to $50 per square foot installed. Material costs $10 to $30 per square foot. Requires sealing and specific grout types that do not scratch the surface.
The national average tile installation project costs $2,116, with most projects falling between $950 and $3,429 per HomeAdvisor data. A 200 square foot kitchen floor typically runs $2,000 to $7,000 depending on tile choice and pattern.
Herringbone and diagonal patterns cost $8 to $20 per square foot in labor because precise cuts take longer. If your budget is tight, a straight or offset pattern uses the same tile at a lower installation cost.
Tips Before You Order
Buy from one dye lot. Tile color varies between production runs. Check the lot number on the box. Order every tile you need from the same lot in one purchase. If a replacement box has a different lot number, return it.
Order one extra box. Damaged tiles happen during installation and years later from impacts. A spare box from the original lot lets you replace a broken tile without sourcing a discontinued product.
Seal grout after installation. Most cement-based grouts are porous. Apply a penetrating grout sealer 72 hours after installation. Reseal every two to three years in wet areas.
Check your subfloor before ordering. Tile cracks when the subfloor flexes. The TCNA standard allows no more than 1/8 inch of variation across a 10 foot span. Fix high spots with a grinder and low spots with floor-leveling compound before tile goes down.
Mix tiles from multiple boxes. Open three or four boxes at once and pull tiles from each randomly as you set them. Subtle color and texture variation exists within a single lot. Mixing boxes distributes that variation so it is not concentrated in one area.
Use tile spacers consistently. A 1/4 inch spacer set on edge gives a 1/8 inch joint. The same spacer laid flat gives a 1/4 inch joint. Confirm the orientation your spacers require before you begin setting tile.
Frequently Asked Questions
How do I calculate how many tiles I need?
Divide your room’s square footage by the square footage of one tile. Multiply the result by 1.10 to add a 10% waste buffer. Round up to the nearest whole tile. For diagonal or herringbone patterns, use 1.15 or 1.20 instead.
How much grout do I need for tile?
For 12×12 tiles with a 1/4 inch joint, plan for roughly 0.5 lbs per 10 square feet. Wider joints and smaller tiles increase that number. The calculator estimates grout weight based on your tile size and joint width. Confirm against the coverage table on your specific product before buying.
What is the standard grout joint width for floor tile?
Most floor tile uses a joint between 1/8 and 3/16 inch. Rectified tile with precise edges can go as narrow as 1/16 inch. Large-format tiles (18 inch and up) typically use 3/16 to 1/4 inch joints.
Should I use sanded or unsanded grout?
Use unsanded grout for joints narrower than 1/8 inch and for polished stone like marble. Use sanded grout for joints 1/8 inch or wider, floors, and high-traffic areas. Sanded grout is stronger and resists cracking in wider joints.
How much does tile installation cost per square foot?
Standard tile installation runs $5 to $15 per square foot including labor and materials. Herringbone and diagonal patterns cost $8 to $20 per square foot due to extra labor. The national average project cost is around $2,116 for a typical bathroom or kitchen floor.
