Measure for Bathroom Tile Accurately: What You’ll Need & Tips

by Lee Wallender

How to measure for bathroom tile correctly—and get the quantity and type tile that’s just right for your bathroom

measure for bathroom tile(Above) Mitzie + Jenifer’s Sweeten renovation

Numbers are stable facts that control our world. So, to measure for bathroom tile on floors or the walls, it would seem that everything is clear-cut, with nothing left open for interpretation. Right?

In this guide, Sweeten outlines how to measure space for bathroom tile, so that in the end, you will have a measurement that lets you purchase the correct quantity of tile. You’ll also calculate for enough extra to make the installation smoother. Sweeten matches home renovation projects with vetted general contractors, offering advice, support, and financial protection—at no cost to the homeowner.

When measuring bathroom dimensions and matching numbers to a physical product—tile—questions will come up.

  • Overage is required, but how much?
  • Should you tile under large bathroom components (like tubs and vanity cabinets)?
  • Does tile seam width change the purchase amount?
  • For wall tile, how far up does the tile go?

What you will measure: 

  1. You will begin with one set of measurements: those that cannot be changed.
  2. Next, you tighten up that set of numbers by taking variables into account.

What you will need to measure for bathroom tile:

Begin with a tape measure, preferably one with a metal blade 1-inch wide or more for rigidity. Do not use a vinyl measuring tape of the type used for clothing and other fabrics. A laser measuring device is a great add-on but is not necessary.

You will also need a simple way to jot down numbers. Pen and paper work best, but if you are working with an app or program, you can use that. Having an extra hand, too, eases the process and produces more accurate numbers.

Getting the fixed dimensions

Certain dimensions in a bathroom are fixed; meaning, they cannot be changed. Begin there.

To measure the bathroom floor tile:

  • Measure the dimensions of the entire bathroom. Measure from one wall to the opposite wall. Then, measure the other walls from side to side. If the room has alcoves or areas in addition to that larger floor space, measure those separately as if they were separate rooms.
  • Measure the available floor space that will be tiled. Measure only the floor area that will be tiled. Rather than subtracting non-tiled areas (such as bathtubs) from the overall dimensions of the room, measure the floor space on its own.

To measure the bathroom wall tile:

  • Full-wall tile runs from the floor to the ceiling. Areas near showers and bathtubs often receive tile from floor to ceiling.

What is a tile wainscot?

  • Tile wainscot is a tile field that runs partially up the bathroom wall. Forty-two inches is a common wainscot height for a bathroom with a 7-foot or 8-foot ceiling. Even better, measure the height of the ceiling, then divide by one-third and use that as your wainscot height.

black and white shower tile

(Above) Jessica + Jessie’s Sweeten renovation

To measure the shower wall and floor tile:

  • Measure all shower walls from side to side and top to bottom. Do not account for the shower pan or shower curb.
  • For the shower pan, measure from side to side in both directions to produce the area measurement.
  • If the curb or threshold will be tiled, assume a height on both sides of at least 2 inches and width of at least 2 inches. Shower curbs may not rise more than 9 inches.

Tips to control for variables:

  • The tape measure will sag, so keep it as straight and level as possible. This is the benefit of having an assistant: to keep the tape measure tight. A laser measuring tool is helpful for distances over 8 to 10 feet, as it produces a straight line.
  • Ignore baseboards, as tile overlaps baseboards. Be sure to measure from wall to wall, not from baseboard to baseboard.
  • Subtract cutouts down to the square foot. Items less than a square foot, such as the toilet flange or shower drain, should not be subtracted.
  • If the sink cabinet will stay in place and you are certain that the bathroom layout will never change, do not tile under the cabinet. Subtract the cabinet from the flooring area.
  • If you think that you will change the bathroom layout in the future, tile underneath the sink cabinet.
  • Tile usually does not run under the shower or bathtub. Do not figure shower or tub floor space into your measurements.
  • Interior tile grout widths range from 1/16-inch to 1/4-inch. Unless this is an unusually large bathroom, do not use grout widths as a variable when measuring for bathroom tile.
  • Site-built showers do not always need tiled shower pans and curbs. You may subtract this quantity of tile if you expect to use a prefabricated shower pan.

Using your measurements to purchase bathroom tile

Once you have a solid set of numbers in hand, it is time to buy the bathroom tile. You will need to consider a few issues before you make the final purchase.

Tile overage: How much extra bathroom tile should I buy?

After you adjust the fixed quantity of tiles with the control variables, you now have the total amount of tile required—almost! The last step is to plan for a standard overage amount of 10% or more.

For example, a 100 square foot bathroom with 10% overage results in a purchase of 110 square feet of tile.

Products may arrive damaged or otherwise unusable. Too many unusable products must be returned, but a broken tile or two may not be worth the effort. More importantly, it is nearly impossible to order exactly the amount of tiles that will be laid down. Field tile edges are typically cut to fit the space. While tile installers strive to recycle cut pieces in other areas of the project, some pieces cannot be used. Boxed tile, too, often ends up with extra tiles left in the box.

Special-shape or unique-size tiles and layout designs

Most tiles are square or rectangular, and most layouts are grid or brick patterns. What happens if you vary the tile size or layout?

Unique tile shapes and sizes require that you purchase more tile. If the tile cannot produce a straight edge when laid, increase the overage to 20% or more.

Layouts that differ from grid or brick patterns also require more tile. Diagonal, herringbone, or chevron patterns, for example, result in cut pieces in a variety of triangular sizes. Some triangles can be used elsewhere, but most cannot.

Other factors for measuring bathroom tile

The ease with which you can return the tiles is an important factor in measuring bathroom tile. A brick-and-mortar store may accept sealed, full-box returns for full value or for full value minus a stocking fee. Online tile suppliers may require you to pay to ship back unused tile.

Having some extra tile on hand has its benefits. Over time, installed tile may crack and need to be replaced. Or you may wish to use the tile for smaller applications within the bathroom, such as for a sink backsplash.

Best tile and applications for bathroom flooring

All bathroom flooring tiles should be specified as such by the manufacturer in the product description or in the technical specifications. Wall-only tile cannot be used for floors, as it is too thin for foot traffic and often too slippery.

Another clue is the COF (or coefficient of friction) slip ratings published by tile manufacturers. For foot traffic, higher numbers are better than lower numbers. Look for a COF rating of 0.50 or more for your floor tile.

Grout seams are necessary between floor tiles. Wide seams impart more friction, thus a safer floor. More seams, too, give the foot friction. This is one reason why mosaic tiles are so popular for floor tiles: the increased proportion of grout to tiles.

Best tile and applications for bathroom walls

Like floor tile, manufacturers often label bathroom wall tile. However, in most cases, you can use bathroom floor tiles for bathroom walls.

One exception is with showers, bathtubs, and other high-moisture areas. Look for tiles with a water absorption rate of 0.5 percent or lower. Tiles labeled specifically with the name “porcelain,” as certified by the Porcelain Tile Certification Agency (PTCA), are guaranteed to fall under the absorption rate range.

Given the visibility of bathroom wall tile, it is often best practice to keep tile seams narrower, to use more routine layouts, and to use tiles with less complex visuals. Highly ornate tiles are acceptable, but are best limited to use in borders or for smaller applications, like backsplashes.

Having a shortage of tile will cause delays, while ordering too much tile affects your budget. Use this guide to measure for bathroom tile accurately and you’ll get even closer to the exact tile quantity you need!

Two ways to keep a renovation project on track and save money: avoid order and delivery hiccups. Read more here.

Sweeten handpicks the best general contractors to match each project’s location, budget, scope, and style. Follow the blog, Sweeten Stories, for renovation ideas and inspiration and when you’re ready to renovate, start your renovation with Sweeten.

Explore other stories