Bathroom Tile Calculator — Floors, Walls, Shower & Tub Surround
Bathrooms tile more surfaces than any other room: the floor, the shower walls, the tub surround, the vanity backsplash, and sometimes even the ceiling. Each surface has its own tile rating, waste factor, and measurement quirks. This page covers every bathroom surface so you can arrive at a single shopping list — and not discover you're a box short at 8 p.m. on installation day.
Measure each bathroom surface separately — floor area (length × width), each shower wall (width × height), and the backsplash strip. Subtract windows and door openings larger than 10 sq ft. Sum all surfaces, divide by the tile area, and add the appropriate waste factor per surface.
In this guide
1Bathroom floor tile — measuring and waste factors
Bathroom floors are simple rectangles in the calculator but rarely simple in practice. Toilets, vanities, and tub alcoves all interrupt the floor area — and each one adds cut complexity.
Measure the full floor length × width, including under the toilet and any freestanding furniture. Subtract only permanently installed base cabinets and built-in tub surrounds that sit on the subfloor. Leave the toilet footprint in the calculation — toilets move for repairs, and you want tile underneath.
Straight / grid: 10–12% (standard bathroom). Brick / running bond: 12–15% (very common for 12×24 plank-style floor tile). Diagonal / 45°: 15–20% (visually expands a small bathroom but cuts every perimeter tile at an angle). Herringbone: 18–22% (premium look, premium waste in small rooms).
A shower floor is almost always a different tile from the shower walls (smaller, higher COF for slip resistance). Measure the shower pan dimensions — typically 3×3 ft or 3×5 ft — and add it as a separate area with 15–20% waste. Mosaic or penny-round tile on a sloped pan produces unusually high waste.
Example: 5×8 ft bathroom floor = 40 sq ft. Subtract the 3×3 ft shower base (9 sq ft) if the shower floor is a different tile = 31 sq ft of main floor. Add 12% waste = 35 sq ft. For the shower base: 9 sq ft + 20% waste = 11 sq ft of mosaic tile. Total order: 35 + 11 = 46 sq ft across two tile types.
2Shower walls — measuring each wall separately
Shower walls require per-wall measurement because corners, the niche, the valve, and the door opening all sit on specific walls — and the cuts around them pile up.
For a standard shower: back wall (width × full tile height), two side walls (depth × tile height). If you have a fourth tiled wall outside the shower threshold, measure it separately. Tile height is typically floor to ceiling, or from the pan to a chair-rail line if you're doing a half-height tile.
Subtract a recessed niche opening if it's tiled inside with a different accent tile (calculate the niche tile separately). Do not subtract the mixing valve, showerhead, or grab bar holes — the cut waste around hardware roughly equals the area saved. Only subtract door openings larger than 10 sq ft.
A 12×24 inch niche has a back panel (2 sq ft) and four jamb strips (totaling about 2 sq ft) — roughly 4 sq ft of tile even though the opening is only 2 sq ft. If you're using mosaic or accent tile inside the niche, calculate it as its own area with a 20% waste factor.
Our wall tile calculator covers shower walls, accent walls, and any other vertical tile surface — including window and fixture subtractions, vertical patterns, and edge-finish math.
3Tub surround — the three-wall calculation
A tub surround tiles three walls from the tub rim to an endpoint (typically 6 feet above the rim, or to the ceiling). It's the second most common bathroom tile project after a full shower.
| Tub size | Back wall | Two side walls | Total area | With 12% waste |
|---|---|---|---|---|
| Standard 5×3 ft tub, tile to 6 ft | 30 sq ft | 36 sq ft (2 × 18) | 66 sq ft | 74 sq ft |
| Standard 5×3 ft tub, tile to ceiling (8 ft) | 40 sq ft | 48 sq ft (2 × 24) | 88 sq ft | 99 sq ft |
| Japanese soaking tub (4×4 ft), tile to 6 ft | 24 sq ft | 48 sq ft (2 × 24) | 72 sq ft | 81 sq ft |
| Freestanding tub (no surround needed) | — | — | Feature wall only | Calculate as accent wall |
Tile height is measured from the top of the tub rim (or the tub deck for a platform tub), not from the floor. The gap between floor and tub rim is usually covered by the tub's integral skirt or a separate tile skirt — measure and calculate that strip separately if it's tiled.
4Tile ratings — which tiles go where in a bathroom
Not every tile can go everywhere. Two ratings matter in a bathroom: PEI (wear resistance) for floors and COF (slip resistance) for wet areas.
| Location | PEI rating | COF needed | Notes |
|---|---|---|---|
| Bathroom floor (main) | PEI 3–4 | 0.5+ (0.6+ wet) | Light to moderate residential traffic |
| Shower floor / pan | PEI 1–3 | 0.6+ wet | Small tile preferred — easier to slope to drain |
| Shower walls | PEI 0–2 | N/A | Must be impervious or vitreous for water resistance |
| Tub surround walls | PEI 0–2 | N/A | Above waterline — vitreous or better |
| Vanity backsplash | PEI 0–2 | N/A | Dry area, any wall-rated tile |
| Heated floor | PEI 3+ | 0.5+ | Check manufacturer compatibility with in-floor heat |
A high PEI rating doesn't mean the tile is waterproof. Shower walls and tub surrounds need a waterproof membrane (Schluter KERDI, RedGard, or similar) behind the tile, regardless of the tile's rating. The membrane, not the tile, stops water from reaching the framing.
5Small bathrooms — typical tile counts by room size
Use this table for a quick sanity-check before plugging real numbers into the calculator. Figures assume 12% waste on a subway-pattern shower and 10% waste on a straight-grid floor.
| Bathroom type | Floor sq ft | Shower/tub walls sq ft | Vanity backsplash | Total (approx.) |
|---|---|---|---|---|
| Powder room (no shower) | 20–25 | — | 3–5 sq ft | 25–30 sq ft |
| 3/4 bath (shower, no tub) | 35–45 | 75–85 sq ft | 3–5 sq ft | 115–135 sq ft |
| Full bath (tub surround) | 40–50 | 70–80 sq ft | 3–5 sq ft | 115–135 sq ft |
| Master bath (separate shower + soaking tub) | 80–120 | 150–200 sq ft | 5–8 sq ft | 235–330 sq ft |
We have dedicated tile-quantity guides for the most searched bathroom room sizes. See how much tile for a 5×8 room and how much tile for an 8×10 room.
6Ordering one batch for the whole bathroom
If you're using the same tile everywhere (a common approach for visual continuity), you can order all surfaces in one batch — but keep a per-surface breakdown so you can verify the total makes sense.
Even if you order one SKU, calculate each surface's waste separately. A 15% waste rate for shower walls applied to the floor area over-orders tile; a 10% rate on the walls leaves you short. The breakdown also helps you check the count after delivery.
Sum all raw square footages (floor + walls + backsplash), then apply waste to the total, not to each surface individually. Applying waste separately per surface rounds up on each one — typically 3–5% more tile than you need. Add surfaces first, waste second.
The biggest advantage of one batch: a single dye lot. Color variation between lots is most visible where floor and wall tile meet. If you order floor and wall tile from two separate lots of the same SKU, the junction line may show a tone difference — especially in natural stone or handmade-look tile.
Pro Tips
- ✓Start with the shower or tub surround. Shower tile takes the most time and produces the most complex cuts. Order and confirm shower tile first; use the leftover margin time to finalize floor and backsplash orders. A shower delay stalls the whole bathroom.
- ✓Use a waterproofing membrane rated for the tile you chose. Large-format tiles require stiffer waterproofing assemblies. KERDI-DS (the thicker version) is recommended for tiles over 15 inches in any dimension. Check the membrane manufacturer's spec before you set a 24×48 slab tile over a standard shower pan.
- ✓Tile the shower floor to the drain, not from the drain outward. Setting layout from the drain produces a ring of small slivers at the shower edge — ugly and hard to grout. Instead, center the layout on the shower pan and let the cuts fall at the perimeter, closest to the walls where the eye won't land.
- ✓Reserve attic stock from every surface. Keep 4–6 spare tiles per surface type. Bathroom tiles crack — soap dishes get hung wrong, toilets fall over during repairs, kids throw things. Matching a tile years later from the same dye lot is nearly impossible once a line is discontinued.
- ✓Use the calculator's surface-mode toggle. The TilePro Calculator has separate wall and floor surface modes. Switch between them to build a per-surface shopping list. Each mode adjusts waste defaults and pattern options for that surface type.
Calculate your bathroom tile in seconds
Enter floor dimensions, shower wall measurements, and tub surround size to get exact tile counts for every bathroom surface. Works for complete remodels and single-surface updates.
Written by the TilePro Editorial Team
Tile-installation researchers and calculator engineers — every guide is grounded in real waste-per-pattern data from the calculator.