Wallpaper Size Required Calculator
Wallpaper Size Required Calculator – Measure & Estimate Easily
Decorating your home with wallpaper can transform plain walls into stunning design features. But before you purchase wallpaper rolls, it’s important to know how much wallpaper you actually need. Buying too little means you’ll run short in the middle of installation, while buying too much wastes money.
That’s why we created this Wallpaper Size Required Calculator – a simple tool to help homeowners, DIY enthusiasts, and professionals quickly estimate the number of wallpaper rolls needed for any room.
In this guide, we’ll cover:
- ✅ Why wallpaper measurement is important
- ✅ How to calculate wallpaper size manually
- ✅ Common mistakes to avoid when measuring walls
- ✅ A free Wallpaper Calculator (with code) you can use directly on your website
- ✅ Practical examples and usage tips
- ✅ FAQs about wallpaper roll coverage and installation
By the end, you’ll know exactly how to measure, calculate, and purchase the right amount of wallpaper rolls with confidence.
Why Do You Need a Wallpaper Size Calculator?
Wallpaper is usually sold in rolls, and each roll has specific dimensions (length × width). Depending on your wall size, windows, doors, and patterns, the number of rolls required varies.
Without proper calculation:
- ❌ You may underestimate and run out of wallpaper halfway.
- ❌ You may overestimate and waste money on extra rolls.
- ❌ Pattern matching may be ignored, leading to visible mismatched seams.
A wallpaper calculator solves these problems by taking your wall measurements, roll size, and wastage allowance into account.
How to Calculate Wallpaper Size Manually
If you prefer manual calculation, here’s a step-by-step method:
Add Wastage (10–15%)
Always add extra for pattern matching, trimming, and mistakes.
Measure the Walls
- Measure the height and width of each wall.
- Multiply height × width to get the area.
- Add all wall areas together.
Wall 1: 10 ft wide × 8 ft tall = 80 sq. ft
Wall 2: 12 ft wide × 8 ft tall = 96 sq. ft
Total = 176 sq. ft
Subtract Doors & Windows
Door: 3 × 7 ft = 21 sq. ft
Window: 4 × 5 ft = 20 sq. ft
Adjusted wall area = 176 – 41 = 135 sq. ft
Check Wallpaper Roll Coverage
Standard wallpaper roll: 21 inches wide (1.75 ft) × 33 ft long = 57.75 sq. ft coverage
Divide Wall Area by Roll Coverage
135 ÷ 57.75 ≈ 2.3 rolls → Buy 3 rolls
How to Use the Wallpaper Calculator
- Measure the height of your wall (in feet).
- Enter the total width of all walls you want to cover (in feet).
- Enter your wallpaper roll width (in inches) and length (in feet).
- Add the total area of doors and windows (in sq. ft) if you want to subtract them.
- Click Calculate.
- The tool shows:
- Total wall area
- Coverage per roll
- Recommended number of rolls (with 10% wastage included)
Common Mistakes When Measuring Wallpaper
- Forgetting openings: Always subtract large windows and doors.
- Ignoring pattern repeat: Some wallpapers require more material to align patterns.
- Not rounding up: Always round up rolls – one extra roll is safer than falling short.
- Mixing units: Be consistent (use feet for height/length, inches for roll width).
Example Calculation
- Wall height: 8 ft
- Total wall width: 20 ft
- Roll size: 21 in (1.75 ft) × 33 ft
- Openings: 30 sq. ft
Wall area = 160 – 30 = 130 sq. ft
Roll coverage = 57.75 sq. ft
130 ÷ 57.75 = 2.25 → Buy 3 rolls
Wallpaper Buying Tips
- Always order rolls from the same batch number to avoid color variation.
- Order at least 1 extra roll for future repairs.
- Consider accent walls vs. full-room coverage.
- Professional installers often recommend 15% extra allowance.
FAQs About Wallpaper Size Calculator
Q1. How many rolls do I need for a 12×12 room?
A: With 8 ft ceilings, total wall area is about 384 sq. ft. A standard roll covers ~57 sq. ft, so you’ll need around 7 rolls (add 1–2 extra for safety).
Q2. Can I use this calculator for peel-and-stick wallpaper?
Yes. As long as you know the roll width and length, the calculation works.
Q3. What if my walls have many windows?
Enter the total square footage of windows/doors in the “Openings” field to subtract them.
Q4. Does pattern matching affect results?
Yes. If your wallpaper has a large repeat (e.g., 25 in), you may need extra rolls. Add 15% extra for safety.
Q5. Should I measure in meters instead of feet?
This calculator uses feet/inches, but you can easily adapt by converting your measurements.
Conclusion
The Wallpaper Size Required Calculator makes it easy to estimate how much wallpaper you’ll need for any room. Instead of guessing or overbuying, you can calculate wall area, subtract windows, check roll coverage, and know exactly how many rolls to purchase.
Whether you’re covering a feature wall or redecorating your entire home, this tool saves time, money, and stress.
👉 Try the calculator above, measure carefully, and order an extra roll to stay safe. With the right planning, your wallpaper project will be smooth, accurate, and beautiful.