How to Determine Backsplash Square Footage

Determine the exact square footage needed for a new backsplash installation with this comprehensive guide. Learn techniques to accurately measure wall space, calculate tile needs, and get the perfect amount of backsplash for your kitchen or bath.


Installing a stylish backsplash is one of the best ways to update your kitchen or bathroom. But before starting any backsplash project, it’s essential to determine the total square footage you’ll need to cover. Knowing the precise backsplash area will help you buy enough tile and materials to complete the job.

Calculating backsplash square footage isn’t difficult, but it does require careful measurement and planning. In this guide, we’ll walk you through the entire process step-by-step. You’ll learn how to measure awkward wall spaces, subtract for windows and appliances, and account for pattern matching and grout. We’ll also provide some handy tips to make your measurements more precise.

Having the right backsplash area figure will save you time, money, and headaches down the road. So let’s get started determining your exact backsplash square footage.

Measuring Wall Length and Height

The first step in finding your backsplash area is accurately measuring the length and height of each wall you want to cover. Here are some tips for getting precise measurements:

Use a Steel Measuring Tape

Avoid flimsy cloth tape measures which can stretch and provide inaccurate readings. Opt for a sturdy retractable steel tape measure instead. Make sure the tape measure’s markings are still legible and double check that it hasn’t stretched or worn out over time.

Measure Multiple Times

Don’t just measure once and assume your number is correct. Measure each wall length at least two or three times to ensure accuracy. Try measuring from different starting points and in both directions. Compare your figures and take an average if they vary slightly.

Account for Uneven Walls

Some walls have dips, bump-outs, or angles that make measurement tricky. In these cases, break the wall into smaller segments and measure each section separately. Then add the figures together to get the total.

Consider Height

Most backsplashes are 4 inches tall, covering the area between countertops and cabinets. But make sure to confirm the desired height with homeowners. Measure from the lowest point of where the backsplash will start to the highest ending point.

Mark Lengths

Use a pencil to lightly mark start and end points on the wall as you measure. This allows you to double check figures later and ensures you measured the correct area.

Record Accurately

Jot down each measurement accurately before moving to the next wall. Rounding up or estimating instead of getting precise figures will throw your final calculation off.

Calculating Total Square Footage

Once you have all the wall length and height numbers measured, it’s time to calculate the total square footage. Here’s a simple formula:

Wall Length x Wall Height = Area of That Wall

To get the total backsplash area:

  1. Multiply the length by height of Wall 1 and write it down.
  2. Do the same for each additional wall area needing backsplash.
  3. Add all wall square footage numbers together.
  4. The final sum is your total backsplash area.

Be sure to account for all backsplash areas in your kitchen or bath, including behind sinks, on accent walls, inside window recesses, and any other spaces that need tiling. Taking your time to precisely measure and calculate will pay off later when you have enough materials purchased.

Dealing with Doors, Windows, and Openings

The previous measurements were based on bare wall spaces. But most rooms also have doors, windows, and other openings that reduce usable backsplash area. Here are some tips for handling these:

Ignore Small Holes

For small holes like electrical outlets or light switches, just ignore the missing space. Trying to subtract a few square inches here and there becomes complicated and won’t affect tile needs much.

Subtract for Doors and Large Openings

Measure doors and openings like inserts for stoves, sinks, etc individually. Get their height and width to find area, then subtract this square footage from your overall walls total.

Measure Window Sills

Determine the length and depth of each window sill that needs tiles. Multiply to get the area and add to your total square footage.

Account for Window Height

For regular windows, simply subtract the window’s height and width measurements from the overall wall space. But for taller windows, only deduct the amount above the planned 4 inch backsplash area.

Adjusting for Outlets, Switches, and Obstacles

Other objects like light switches, electrical outlets, pipes, and vents also take up backsplash space. But trying to subtract tiny measurements for each item becomes tedious and may leave gaps in your tile layout.

Instead of deducting, use this time-saving formula:

Total Wall Space x 0.80 = Adjusted Space for Obstacles

So if your total backsplash area based on wall measurements was 80 square feet, multiply this by 0.80 to account for an estimated 20% taken up by outlets, switches, etc.

This provides a quick 15-20% deduction rather than painstakingly measuring every tiny object. Be sure to account for larger obstructions like ducting separately by subtracting their individual area.

Planning Repeating Patterns

Many backsplashes use decorative tiles set in repeating grids or patterns. To ensure you purchase enough tiles to complete the pattern across all walls, here are some tips:

  • Determine the dimensions of the tile itself first (12 x 12 inches, 4 x 4 inches, etc).
  • Sketch how the tiles will be laid out on each wall space. Plan where the pattern will need to repeat.
  • Measure the length and height of one full pattern repeat section.
  • Calculate the square inches or feet for one full pattern.
  • Divide your total backsplash area by the pattern repeat area.
  • Round up decimals to determine how many full pattern repeats you need.
  • Multiply this by individual tiles needed per repeat to find the total number of tiles required.

Planning repeats helps prevent frustration from running out of tiles partway through the job.

Allowing for Grout Lines and Cuts

When calculating tile needs, be sure to account for the spacing between tiles. Grout lines consume additional area, meaning you’ll need more tiles:

  • Determine grout line width based on the tile size and design. Common grout lines are 1/8 or 1/16 inch.
  • Multiply your total backsplash square footage by 105% for 1/16 inch grout or 110% for 1/8 inch grout.
  • This provides 5-10% more tiles to accommodate grout spacing.

Also factor in tiles that will need to be cut for edges and openings. Add an extra 10% onto your tile count for cuts to be safe.

Measuring Carefully for Diagonal Layouts

Laying tiles on a diagonal requires extra planning and precision. Diagonal patterns need roughly 30% more tiles than a straight grid layout.

To calculate diagonal area:

  • Mark a test diagonal section on the wall using a level and tape measure. Make diagonal lines the exact size and angle you want.
  • Measure from corner to corner horizontally and vertically within this diagonal space.
  • Multiply the two measurements and divide by 2 to get the diagonal section area.
  • Use this process in each part of the wall to get the total diagonal square footage.
  • Multiply the total diagonal area by 1.3 to account for the extra tiles needed.

Adding a Design Margin

Most pros recommend purchasing 10-15% extra tiles beyond what you calculated to be safe. This provides a cushion for:

  • Breakage or damaged tiles you need to replace
  • Alignment issues requiring additional cuts
  • Pattern extensions or mistakes in layout
  • Future repairs if tiles become cracked or missing

Carefully planning upfront means you shouldn’t need the extra tiles, but having spares is useful in case any surprise issues come up.

Double Checking Figures

Always double check your final square footage measurements and tile counts before making purchases. It’s easy to miss a calculation step or have minor errors add up.

Review all of your figures to confirm:

  • Original wall measurements are accurate with multiple checks
  • You subtracted openings and obstacles correctly
  • Any patterns or diagonals were calculated precisely
  • You added proper percentages for grout and spares

Having a second set of eyes review the figures is helpful too. Follow this entire process correctly and you’ll determine the perfect backsplash square footage.


How do I measure for backsplash in irregular spaces?

For odd shaped walls, break the area into smaller rectangles or squares that you can measure individually. Measure any protruding nooks or crevices separately, then add all the measurements together for the total.

What’s the best way to measure height?

Use a steel tape measure and have someone hold the end at the top point. Be sure the tape is straight up and down, not angled. Mark the bottom point with pencil then measure to get the exact height.

What if my backsplash design has multiple materials?

Make separate calculations for each material or tile type needed following the same square footage measuring process. Determine amounts needed based on where each product will be installed.

Can I install backsplash over existing tile?

Yes, you can install a new backsplash over existing tile or another finished wall surface. Be sure to use appropriate adhesives, prepare the surface properly, and account for the extra thickness in your measurements.

How do I calculate for a mosaic backsplash?

Measure area as you would for normal tile. Determine the mosaic sheet size and how sheets will be laid out. Multiply area by 1.15 to account for 15% grout and cuts. Round up and multiply by the number of mosaic sheets needed per square foot to determine quantity.

What’s the standard height for a backsplash?

Most backsplashes install between 4-6 inches high. Measure from the countertop or vanity top up the wall to find your exact backsplash height. Standard backsplash height protects the wall from splashes without overwhelming the space.

How do I know how much tile to buy?

Multiplying the backsplash square footage by the number of tiles needed per square foot will tell you how many tiles are required. Add 10% for cuts and breakage. Check tile requirements for the pattern or design you choose.

What if I ordered too much tile?

Keep any unopened tile boxes stored safely for future repairs or additions. You may also be able return extra tiles to the store if you have receipts. Only open the number of boxes immediately needed so tiles won’t disappear or get damaged before being installed.


Determining the right amount of backsplash takes careful planning and measurement. Follow this guide to accurately calculate your wall space, account for openings and obstacles, plan patterns, and add extras as needed. Taking time upfront to determine backsplash square footage exactly will help your project go smoothly.

With some simple math and tile layout mapping, you’ll get the perfect tile count to finish your backsplash beautifully. Just be sure to double check all figures and allow a cushion for mistakes or changes down the road. Use these tips to measure like a pro so you can install a stunning new backsplash that transforms your space.