Wallpaper calculator square feet
Stop guessing – this advanced wallpaper calculator uses your sample measurements, confidence levels, and even model year to give you a reliable estimate. Perfect for international use, based on standard statistical methods, and built for accuracy.
How to use this calculator – simple steps
Just grab a tape measure and follow these steps. You’ll get an estimated range plus a visual breakdown.
- Measure a few walls – pick at least 2–3 walls that represent your room (area in sq ft).
- Enter sample data as a comma‑separated list (e.g., 120, 135, 110).
- Total number of walls – include every wall you plan to cover (even if you didn’t measure all).
- Choose confidence level – how sure you want to be about the range.
- Select model year – affects the assumed roll size (modern rolls are slightly larger).
- Click calculate – see your estimated total area, rolls needed, and the confidence interval.
Enter your measurements & preferences
All fields are required. Use the placeholders as a guide.
Your statistical wallpaper estimate
Based on your sample and confidence level, here’s the projected area and rolls. The graph shows your individual wall samples.
Estimated total area
—
(mean estimate)Confidence interval
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(for total walls)Rolls needed (mean)
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based on roll sizeBar chart: each bar is a wall area from your sample. The dotted line is the sample mean.
Understanding every factor & result
We’ve designed this calculator to be transparent. Below you’ll find detailed tables explaining each input, output, and how to interpret the stats.
Input factors explained
| Field | Description | Example |
|---|---|---|
| Sample data | Areas of individual walls you measured (minimum 2). | 120, 135, 110, 128 |
| Total walls | How many walls you will paper (even if not measured). | 4 |
| Confidence level | Statistical certainty that true average lies in the interval. | 95% |
| Model year | Adjusts roll size (approx. 56 ft² for 2024, +1 ft² per year). | 2024 → 56 ft²/roll |
Output statistics – what they mean
| Result | Interpretation |
|---|---|
| Estimated total area | Sample mean × total walls – your best single guess. |
| Confidence interval (lower – upper) | Range that likely contains the true total area, given your confidence level. |
| Rolls needed (mean / low / high) | Number of rolls based on mean estimate and the interval bounds (rounded up). |
Statistical confidence – plain language
| Confidence level | What it means |
|---|---|
| 90% | If you repeated this sampling many times, 90 out of 100 intervals would contain the true area. |
| 95% | Most common in research – balances certainty and width. |
| 99% | Very high certainty, but the interval will be wider. |
Frequently Asked Questions
How do I measure my walls for this calculator?
Measure the width and height of each wall in feet, then multiply to get square feet. Enter those areas as sample data (comma separated). If you have many identical walls, measure a few as samples.
What confidence level should I use?
95% is standard for most projects. If you want a narrower range (more precision), choose 90%. For maximum certainty (but wider range), choose 99%.
How does model year affect roll size?
Wallpaper roll sizes can vary slightly by year. Our calculator uses a simple trend: 56 ft² for 2024, 57 ft² for 2025, 58 ft² for 2026, and a linear adjustment for other years. You can override by entering a custom year.
What if my sample data doesn’t include all walls?
You need to enter the total number of walls in the project. The calculator uses your sample to estimate the average wall area, then multiplies by that total. The confidence interval reflects uncertainty from the sample.
Can I use metric measurements?
Yes, but all areas must be in square feet. If you have measurements in square meters, multiply by 10.764 to convert to square feet before entering.
Use the Paver Calculator (Square Feet) for accurate paving estimates, or explore the full Feet & Inches Measurement Calculator category for all measurement and feet/inches tools.