Accurately estimate the wallpaper needed for your project.
Wallpaper Area Calculator
Enter the length of the room in feet.
Enter the width of the room in feet.
Enter the height of the room in feet.
Sum of the areas of all windows (width x height).
Sum of the areas of all doors (width x height).
Standard wallpaper roll width is typically 20.5 inches.
Standard wallpaper roll length is typically 33 feet.
Your Wallpaper Needs
Total Wallpaper Needed (sq ft)—
Total Wall Area (sq ft)—
Paintable Wall Area (sq ft)—
Rolls Needed (approx.)—
Wallpaper Sq Ft per Roll—
Formula: Wall Area = (2 * Room Length + 2 * Room Width) * Room Height. Paintable Area = Wall Area – Window Area – Door Area. Wallpaper Needed (sq ft) is calculated by dividing the Paintable Area by the wallpaper's pattern repeat coverage factor (assumed 0.75 for waste/matching). Rolls Needed = Total Wallpaper Needed / Wallpaper Sq Ft per Roll.
Wallpaper Usage Breakdown
Paintable Area Non-Paintable Area (Windows/Doors) Waste/Pattern Match
Estimated breakdown of wallpaper area requirements.
Input Summary
Parameter
Value
Unit
Room Length
—
ft
Room Width
—
ft
Room Height
—
ft
Total Window Area
—
sq ft
Total Door Area
—
sq ft
Wallpaper Roll Width
—
inches
Wallpaper Roll Length
—
ft
Summary of the dimensions and wallpaper specifications entered.
Understanding Your Wallpaper Needs: A Deep Dive into the Square Feet Calculator for Wallpaper
What is a Wallpaper Square Feet Calculator?
A Wallpaper Square Feet Calculator is a specialized tool designed to help homeowners, designers, and contractors accurately estimate the total amount of wallpaper required for a specific room or area. It takes into account the dimensions of the walls, subtracts areas that won't be wallpapered (like windows and doors), and then calculates how many rolls of wallpaper are needed based on the dimensions of a standard wallpaper roll. The primary goal is to prevent under-buying, which leads to costly delays and potential pattern matching issues, or over-buying, which results in unnecessary expense and waste.
Who should use it: Anyone planning to wallpaper a room, including:
DIY homeowners embarking on a decorating project.
Interior designers specifying materials for clients.
Professional painters and decorators ensuring they have adequate supplies.
Renovators and flippers estimating project costs.
Common misconceptions: A frequent misunderstanding is that simply measuring the perimeter of the room and multiplying by the height will suffice. This overlooks crucial factors like window/door cutouts, the need for extra material for pattern matching (pattern repeat), and trimming waste. Another misconception is that all wallpaper rolls are the same size; while standards exist, variations can occur.
Wallpaper Square Feet Calculator Formula and Mathematical Explanation
The calculation involves several steps to determine the final wallpaper quantity. The core idea is to find the total area to be covered and then divide it by the usable area provided by each roll of wallpaper, factoring in waste.
Step 1: Calculate the Total Gross Wall Area. This is the combined surface area of all four walls before accounting for openings.
Total Wall Area = (2 * Room Length + 2 * Room Width) * Room Height
Step 2: Calculate the Paintable Wall Area. This subtracts the areas that will not be covered by wallpaper.
Paintable Wall Area = Total Wall Area - Total Window Area - Total Door Area
Step 3: Calculate the Usable Square Footage Per Roll. This considers the standard dimensions of a wallpaper roll and accounts for pattern matching and waste. A common industry practice is to assume about 75% usability due to pattern repeats and trimming, though this can vary.
First, convert roll width from inches to feet: Roll Width (ft) = Roll Width (inches) / 12
Square Feet Per Roll (Gross) = Roll Width (ft) * Roll Length (ft)
Usable Square Feet Per Roll = Square Feet Per Roll (Gross) * 0.75 (This 0.75 is an assumed waste factor).
Step 4: Calculate the Total Wallpaper Needed (in Square Feet). This is the paintable area, often increased slightly to ensure enough material for cuts and pattern alignment.
Total Wallpaper Needed (sq ft) = Paintable Wall Area / 0.75 (This 0.75 factor assumes you'll need ~25% extra for matching and waste. Some prefer to use a higher factor or simply add a percentage).
Step 5: Calculate the Number of Rolls Needed.
Rolls Needed = Total Wallpaper Needed (sq ft) / Usable Square Feet Per Roll
Since you can't buy partial rolls, the result is typically rounded up to the nearest whole number. Our calculator provides an approximation based on these principles.
Variables Table:
Variable
Meaning
Unit
Typical Range
Room Length
The longer dimension of the room's floor plan.
Feet (ft)
5 – 50+
Room Width
The shorter dimension of the room's floor plan.
Feet (ft)
5 – 50+
Room Height
The vertical distance from floor to ceiling.
Feet (ft)
6 – 15+
Window Area
The total surface area of all windows to be excluded.
Square Feet (sq ft)
0 – 100+
Door Area
The total surface area of all doors to be excluded.
Square Feet (sq ft)
0 – 50+
Wallpaper Roll Width
The width of a single roll of wallpaper.
Inches (in)
18 – 36 (Commonly 20.5)
Wallpaper Roll Length
The length of a single roll of wallpaper.
Feet (ft)
20 – 35 (Commonly 33)
Total Wall Area
Gross surface area of all walls.
Square Feet (sq ft)
Calculated
Paintable Wall Area
Net area to be covered by wallpaper.
Square Feet (sq ft)
Calculated
Wallpaper Sq Ft per Roll
Usable area from one roll, accounting for waste.
Square Feet (sq ft)
Calculated (e.g., ~50-70 sq ft)
Total Wallpaper Needed
Estimated total sq ft required, including waste.
Square Feet (sq ft)
Calculated
Rolls Needed
Number of wallpaper rolls to purchase.
Whole Rolls
Calculated (rounded up)
Practical Examples (Real-World Use Cases)
Example 1: Standard Living Room
Consider a living room with the following dimensions:
Room Length: 15 ft
Room Width: 12 ft
Room Height: 8 ft
Total Window Area: 20 sq ft
Total Door Area: 21 sq ft
Wallpaper Roll Width: 20.5 inches
Wallpaper Roll Length: 33 ft
Calculation:
Total Wall Area = (2 * 15 + 2 * 12) * 8 = (30 + 24) * 8 = 54 * 8 = 432 sq ft
Paintable Wall Area = 432 – 20 – 21 = 391 sq ft
Wallpaper Sq Ft per Roll (Gross) = (20.5 / 12) * 33 ≈ 1.71 * 33 ≈ 56.4 sq ft
Usable Square Feet Per Roll ≈ 56.4 * 0.75 ≈ 42.3 sq ft
Total Wallpaper Needed (sq ft) = 391 / 0.75 ≈ 521.3 sq ft
Rolls Needed = 521.3 / 42.3 ≈ 12.3 rolls
Result: You would need to purchase 13 rolls of wallpaper. This accounts for the paintable area plus an estimated 25% for waste and pattern matching.
Interpretation: This calculation highlights that simply covering the paintable area (391 sq ft) is insufficient. The buffer for waste and pattern matching significantly increases the total required amount, making it crucial to factor in.
Example 2: Small Bedroom with Minimal Openings
Consider a smaller bedroom:
Room Length: 10 ft
Room Width: 10 ft
Room Height: 8 ft
Total Window Area: 10 sq ft
Total Door Area: 19 sq ft
Wallpaper Roll Width: 20.5 inches
Wallpaper Roll Length: 33 ft
Calculation:
Total Wall Area = (2 * 10 + 2 * 10) * 8 = (20 + 20) * 8 = 40 * 8 = 320 sq ft
Paintable Wall Area = 320 – 10 – 19 = 291 sq ft
Wallpaper Sq Ft per Roll (Gross) ≈ 56.4 sq ft
Usable Square Feet Per Roll ≈ 42.3 sq ft
Total Wallpaper Needed (sq ft) = 291 / 0.75 ≈ 388 sq ft
Rolls Needed = 388 / 42.3 ≈ 9.17 rolls
Result: You would need to purchase 10 rolls of wallpaper.
Interpretation: Even in a smaller space, the waste factor significantly impacts the quantity. It's always better to have a little extra for mistakes or future repairs than to run short.
How to Use This Wallpaper Square Feet Calculator
Using this calculator is straightforward. Follow these steps to get accurate wallpaper estimates:
Measure Your Room: Use a tape measure to accurately determine the length, width, and height of the room in feet.
Measure Openings: Measure the width and height of each window and door that you will not be wallpapering. Calculate their individual areas (Width x Height) and sum them up to get the Total Window Area and Total Door Area.
Note Wallpaper Specs: Check the packaging or product description for your chosen wallpaper to find its roll width (usually in inches) and roll length (usually in feet). Standard sizes are pre-filled but verify.
Enter Data: Input all the measured values into the corresponding fields in the calculator.
Calculate: Click the "Calculate" button.
How to read results:
Total Wall Area (sq ft): The total surface area of the walls without deductions.
Paintable Wall Area (sq ft): The actual area that will be covered by wallpaper after deducting windows and doors.
Wallpaper Sq Ft per Roll: The estimated usable area you can get from a single roll, considering standard waste.
Total Wallpaper Needed (sq ft): The overall square footage required, including an allowance for pattern matching and trimming.
Rolls Needed (approx.): The final number of rolls you should purchase. This is always rounded up to the nearest whole number.
Decision-making guidance: Always round up the number of rolls needed. It's far better to have one or two extra rolls than to run short, especially if the wallpaper is no longer in production or dye lots differ. Keep leftover rolls for future repairs.
Key Factors That Affect Wallpaper Square Feet Results
Several elements influence the amount of wallpaper you'll need beyond basic room dimensions. Understanding these can lead to a more precise estimate:
Pattern Repeat: This is arguably the most critical factor after wall area. Wallpaper designs often have a "pattern repeat" – the vertical distance before the pattern starts to align again. Larger repeats require more paper to be cut off to achieve a match, significantly increasing waste. Always check the pattern repeat on the wallpaper specifications.
Room Shape and Complexity: Rooms with many corners, alcoves, or architectural details (like wainscoting or chair rails) require more cuts and potentially more waste than simple rectangular rooms.
Obstructions: Beyond standard windows and doors, other features like radiators, built-in cabinets, fireplaces, or large wall-mounted fixtures might need to be worked around, increasing cutting and fitting challenges.
Wallpaper Roll Size Variations: While 20.5 inches wide and 33 feet long is common (US standard), rolls in other regions or for specialty papers can differ (e.g., European rolls are often narrower and shorter). Always verify the dimensions of the specific product you are using.
Installation Skill Level: An experienced installer might be able to minimize waste more effectively than a beginner. However, it's wise for anyone to add a small buffer for potential errors, especially on the first few strips.
Ceiling Height Variations: While most rooms have consistent ceiling heights, sloped ceilings or multi-level rooms require more complex calculations and potentially more material due to angled cuts.
Direction of Pattern Match: Some patterns require a straight match (where the pattern aligns perfectly on adjacent strips), while others might need a drop match (where the pattern needs to be shifted vertically). Drop matches generally lead to more waste.
Purchasing Strategy: Buying wallpaper in batches is crucial. Ensure all your rolls come from the same dye lot to guarantee consistent color. Ordering slightly more than calculated accounts for unforeseen issues and ensures uniformity. Consider bulk discounts if available for larger projects.
Frequently Asked Questions (FAQ)
Q1: How do I calculate the area of a window or door?
Multiply the height of the window/door by its width. For example, a window that is 4 feet high and 3 feet wide has an area of 12 square feet (4 * 3 = 12).
Q2: What is a "pattern repeat" and why is it important?
A pattern repeat is the vertical distance on the wallpaper where the design starts to replicate itself. A larger repeat means you'll likely discard more wallpaper from each strip to ensure the pattern aligns correctly across seams, increasing the total amount needed.
Q3: Should I always round up the number of rolls?
Yes, absolutely. It's standard practice to round up to the nearest whole roll. Running short is a common and costly mistake, as dye lots can vary between batches, making it difficult to find a perfect match later.
Q4: What does "dye lot" mean in wallpaper?
A dye lot is a batch number assigned during the manufacturing process. Wallpaper from the same dye lot will have consistent color. It's crucial to ensure all the rolls you purchase for a project share the same dye lot to avoid color discrepancies on your walls.
Q5: Can I use this calculator for ceilings?
This calculator is primarily designed for vertical walls. Calculating wallpaper for ceilings involves different geometry and potentially different waste factors, especially if the ceiling is not flat. You would typically calculate the ceiling area (Length x Width) and then add a significant percentage (20-30% or more) for waste and cuts.
Q6: What if my room has a standard 8-foot ceiling? Do I need special calculations?
No, the calculator handles standard ceiling heights perfectly. Just input the height accurately. For very high ceilings (over 10-12 feet), the total wall area increases significantly, requiring more wallpaper.
Q7: How much extra wallpaper should I buy for a complex pattern?
For complex patterns or large pattern repeats, consider adding an extra 10-20% to your calculated needed square footage (or factor this into your waste percentage in the calculator if it allows). It's always better to err on the side of caution.
Q8: What are the standard dimensions for a wallpaper roll?
In the US, a standard single roll is typically 20.5 inches wide and 33 feet long, yielding approximately 56.4 square feet of paper. However, it's crucial to remember that usability is reduced by pattern matching and trimming, often bringing the effective coverage down to around 40-50 square feet per roll.
Q9: What if I want to wallpaper around a large feature like a fireplace?
Treat the non-wallpapered area around the feature as you would a large window or door. Measure its dimensions, calculate the area, and subtract it from the total wall area. You might also need to factor in extra cuts for fitting around the feature.