Tile Calculator
Enter your room dimensions and tile size to instantly calculate how many tiles, boxes, grout, and adhesive you need — including your chosen waste factor.
Room Dimensions
Tile Specifications
Shopping List
| Item | Quantity | Notes |
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* Tile count assumes a zero-width grout joint; the waste factor covers cuts and breakage. Grout coverage varies by manufacturer and joint size. A standard 25 lb bag typically covers 50–200 sq ft depending on tile size and joint width — verify on the bag label before purchasing. Thin-set adhesive coverage is approximately 40–50 sq ft per 50 lb bag for floor tile; verify with your product's technical data sheet.
How the Formula Works
Every result above is calculated live using the formulas below. No rounding occurs until the final box count.
Step 1 — Room area
room_area_sqft = length_ft × width_ft If metres selected, each dimension is multiplied by 3.28084 before the area calculation.
Step 2 — Single tile area
tile_area_sqft = (tile_length_in / 12) × (tile_width_in / 12) Step 3 — Tiles needed (with waste)
tiles_needed = ⌈ (room_area_sqft / tile_area_sqft) × (1 + waste_pct / 100) ⌉ Ceiling (⌈…⌉) means always round up — you cannot buy a fraction of a tile.
Step 4 — Boxes to buy
boxes = ⌈ tiles_needed / tiles_per_box ⌉ Step 5 — Grout estimate (lbs)
grout_lbs = ((tile_L + tile_W) / (tile_L × tile_W)) × joint_width × 0.375 × 14.4 × room_area_sqft Standard industry grout weight formula. Tile depth assumed at 3/8" (0.375 in). Factor 14.4 is an empirically-calibrated constant for sanded grout derived from industry coverage data — it is not a direct density conversion (100 lb/ft³ would give ~8.33, not 14.4). Always verify against the coverage table on your specific grout bag.
Other Flooring Calculators
Guides & Resources
- How Much Tile Do I Need? (Step by Step With Waste Factor)
- Tile Waste Percentage Explained (10% vs 15% vs 20%)
- How to Measure a Room for Tile (Irregular Rooms & Niches)
- Tile Size Guide: Common Sizes and Where Each Works
- How to Estimate Grout and Thinset for a Tile Job
- Subway Tile Layout Patterns and How They Change Quantity
- Bathroom Tile Estimating Checklist (Floor + Walls + Wainscot)
- Flooring Calculators Hub (Laminate, Vinyl Plank, Hardwood)
- How Much Paint Do I Need? (Room Paint Estimating Guide)
- Underlayment & Backer-Board Estimating Guide
- How Much Wallpaper Do I Need? (Rolls & Repeat Guide)
Frequently Asked Questions
Divide the room area (length × width in square feet) by the area of one tile, then multiply by your waste factor (1.10 for 10% waste is standard). Round up to the nearest whole tile, then divide by the number of tiles per box and round up again. This calculator does all of that for you automatically.
Use at least 10% waste for a straightforward rectangular room with a simple grid layout. Use 15% for rooms with many cuts (around cabinets, toilets, alcoves). Use 15–20% for diagonal or herringbone patterns that require more cut tiles. Always buy at least one full box extra to keep for future repairs.
It varies widely. Small mosaic tiles (1×1 or 2×2 in) may have 100+ per box. Standard 12×12 in floor tiles often come 10–20 per box. Large-format 24×24 in tiles may have only 4–6 per box. The box label always lists the tile count and total square footage. Enter your actual box count in the "Tiles per Box" field above.
Grout quantity depends on tile size, joint width, and tile thickness. The calculator uses the standard industry formula shown in the "How the Formula Works" section below the tool. Bag coverage varies widely by brand and joint size — always verify on the bag label before purchasing.
Yes — enter the wall height as "length" and wall width as "width." For a backsplash, measure the area to be tiled (e.g. 2 ft tall × 8 ft wide = 16 sq ft). The formula is identical regardless of orientation. You may want a lower waste factor (5–10%) for backsplash work because fewer cut tiles are typically needed.