Bathroom Remodel Materials Estimate: Floor, Walls, Shower, and Paint
October 21, 2026
Bathrooms are small, but they pack a lot of cost into very few square feet, because they combine plumbing, waterproofing, tile, fixtures, ventilation, and electrical work. Estimating materials by surface area is a reliable way to start a budget. Measure each surface, apply waste factors, and then add fixtures and labor.
In this example, a bathroom measures 5 feet by 8 feet with 8-foot ceilings. The tub or shower occupies one 5-foot end, and the rest of the room has a vanity and toilet.
Skip the math and get your answer instantly:
Open the Square Footage Calculator →Floor Area
The floor is 5 × 8 = 40 square feet. Subtract the footprint of the tub if you will not tile under it (a 5-foot tub is 5 × 2.5 = 12.5 square feet), but keep in mind that you may need waterproofing and a pan under a shower. Add 10% waste for tile: 40 × 1.1 = 44 square feet for the floor if you treat the whole floor as tiled. For a smaller tiled area of 27.5 square feet, you would buy about 30.
Choose tiles suited to wet floors. Small mosaics and textured finishes give better traction, as measured by slip resistance ratings such as DCOF 0.42 or higher.
Shower or Tub Surround
For a three-wall surround running from the floor to 8 feet, the wall area is 2 side walls of 2.5 × 8 = 20 square feet each, plus the back wall of 5 × 8 = 40 square feet, for 80 square feet. A full-height shower is typical; a tub surround might only go to 6 or 7 feet. Subtract the window and door openings. Add 15% waste for wall tile because of the many cuts: 80 × 1.15 = 92 square feet.
If you tile the whole bathroom walls to 4 feet as a wainscot, the perimeter of 26 feet gives 26 × 4 = 104 square feet before subtracting openings.
| Surface | Net area | Waste | Order quantity |
|---|---|---|---|
| Floor | 40 sq ft | 10% | 44 sq ft |
| Shower or tub surround (3 walls x 8 ft) | 80 sq ft | 15% | 92 sq ft |
| Wainscot tile (26 ft perimeter x 4 ft) | 104 sq ft | 15% | 120 sq ft |
Paint and Drywall
Wall area above the tile: for the part of the room not tiled, say 26 × 8 = 208 square feet minus the shower wall area, door, and window. Bathrooms need moisture-resistant paint with a satin or semi-gloss finish. One gallon typically covers 350 to 400 square feet, so a single gallon covers two coats on 150 to 180 square feet. The ceiling is another 40 square feet.
If you replace damaged drywall, use moisture-resistant (green board) or cement board behind tile. A 4 × 8 sheet is 32 square feet, so the three shower walls need about three sheets.
Fixtures, Plumbing, and Ventilation
Allow for a vanity, toilet, faucets, shower valve, lighting, mirror, accessories, and an exhaust fan sized for the room. A common guideline is 1 CFM (cubic feet per minute) per square foot, with a minimum of 50 CFM, so a 40-square-foot bathroom needs at least 50 CFM. Venting to the outdoors prevents moisture damage and mold.
Moving plumbing fixtures adds cost, so keep them in the same locations when possible.
Budget and Contingency
Renovation surprises are common: hidden rot, outdated wiring, or out-of-plumb walls. Set aside a contingency of 15% to 20% of the estimated cost. Get several quotes for labor, and compare the scope line by line. Order tile first because lead times can be long, and the dimensions of other materials depend on it.
Order of Work
Demolition, rough plumbing and electrical, framing repairs, waterproofing, backer board, tile, grout, paint, then fixtures. Following this order prevents damage to finished surfaces. Inspections may be required after the rough work.
Frequently Asked Questions
How much tile do I need for a 5x8 bathroom floor?
40 square feet of floor plus 10% waste, about 44 square feet.
How much waste should I allow for wall tile?
Typically 15% because of cuts around corners, niches, and fixtures.
What size exhaust fan do I need?
About 1 CFM per square foot, with a minimum of 50 CFM.
Should I use green board behind shower tile?
Cement board or a waterproof membrane system is the recommended backer in wet areas.
How much contingency should I plan?
15% to 20% of the estimated cost is a sensible cushion.