Getting ready to install wallpaper is exciting—but before you click “order,” there’s one step you can’t afford to get wrong: measuring your walls. Ordering too little wallpaper can delay your project, while ordering too much wastes money. A precise approach ensures you get exactly what you need the first time.
This wallpaper measurement guide will walk you through the process step-by-step so you can measure confidently and avoid common pitfalls.
Why Accurate Measurement Matters
Wallpaper isn’t like paint. With paint, you can usually buy an extra gallon if needed and blend it in. Wallpaper, however, comes in dye lots and patterns. If you run short, the next batch may not match perfectly—especially with patterned designs.
Accurate measurements help you:
- Avoid visible mismatches between rolls
- Reduce material waste
- Stay within budget
- Keep your project timeline on track
Tools You’ll Need
Before you begin, gather a few basic tools:
- Tape measure (preferably 25 ft or longer)
- Pencil and paper (or notes app)
- Calculator
- Step ladder (for taller walls)
Step 1: Measure Wall Height
Start by measuring the height of your wall from floor to ceiling.
- Measure in multiple places—especially in older homes where ceilings may not be perfectly level.
- Use the tallest measurement to be safe.
Write this number down in inches. Wallpaper calculations are typically more precise when done in inches rather than feet. For ease of calculating rolls, use our Wallpaper Roll Estimator on designcalculators.com
Step 2: Measure Wall Width
Next, measure the width of each wall you plan to cover.
- Measure from corner to corner
- For multiple walls, measure each one separately, then add them together
If your room has windows, doors, or large openings, don’t subtract them just yet. It’s usually safer to include them in your total to account for pattern matching and trimming waste.
Step 3: Calculate Total Square Footage
To estimate your wall area:
- Multiply wall height × wall width for each wall
- Add all totals together
This gives you a general sense of coverage, but wallpaper is sold in rolls—not square feet—so there’s another step.
Step 4: Understand Wallpaper Roll Coverage
Wallpaper typically comes in two standard sizes:
- Single roll: About 20–30 square feet
- Double roll (most common): About 56–60 square feet
Always check the manufacturer’s specifications because roll sizes vary.
However, coverage isn’t just about square footage. You also need to factor in pattern repeat.
Step 5: Account for Pattern Repeat
Pattern repeat is the vertical distance between where a design starts and where it repeats again.
- Small or no pattern: minimal waste
- Large or complex patterns: more waste due to alignment
For example, a 24-inch repeat means you may need extra length per strip to align the pattern correctly.
This is one of the biggest reasons people underestimate how much wallpaper they need.
Step 6: Calculate Number of Strips Needed
Wallpaper is installed in vertical strips (called drops).
To determine how many strips you need:
- Divide total wall width by the width of one wallpaper roll (usually 20–21 inches)
- Round up to the nearest whole number
Step 7: Calculate Strips Per Roll
Now determine how many full strips you can get from one roll.
- Divide the roll length by your wall height (including extra for trimming and pattern repeat)
- Round down to a whole number
Step 8: Determine Total Rolls Needed
Finally:
- Divide total strips needed by strips per roll
- Round up- Always round up—and consider ordering one extra roll for safety.
Common Mistakes to Avoid
Even careful DIYers make these errors:
1. Ignoring pattern repeat
This is the most common issue and leads to under-ordering.
2. Subtracting windows and doors
While it seems logical, this often backfires due to pattern waste.
3. Measuring only once
Always double-check your measurements to avoid costly errors.
4. Forgetting trimming allowance
Add a few extra inches to each strip for top and bottom trimming.
Pro Tips for Better Results
- Measure each wall separately for accuracy
- Take photos and notes if working across multiple rooms
- Label your measurements clearly
- When in doubt, order slightly more—not less
If you want to simplify the math, using a wallpaper roll calculator can speed up the process and reduce errors. Tools like our Wallpaper Calculator can help when coordinating wallpaper ensuring your entire project stays consistent and well-planned.
Final Thoughts
Measuring for wallpaper might seem tedious, but it’s the foundation of a successful project. Taking the time to do it right saves you money, prevents frustration, and ensures a polished result.