Wallpaper Calculator

Add each wall you plan to wallpaper. For rooms with uniform height, just change the width per wall.

Doors

Windows

Calculation Method

The wallpaper calculator estimates the number of rolls needed using these steps:

1. Total wall area = sum of each wall’s width × height
2. Opening area = sum of all door and window areas (width × height × quantity)
3. Coverable area = total wall area − opening area
4. Usable strips per roll = roll length ÷ adjusted strip height (wall height rounded up to the next pattern repeat)
5. Usable area per roll = usable strips × strip width × wall height
6. Rolls needed = coverable area ÷ usable area per roll (rounded up)

Pattern Repeat

When wallpaper has a repeating pattern, each strip must be cut longer than the wall height so the pattern aligns between strips. The effective strip height becomes:

Effective height = ⌈wall height ÷ pattern repeat⌉ × pattern repeat

This extra material is waste from pattern matching. Larger pattern repeats mean more waste per strip and fewer usable strips per roll.

Standard Roll Sizes

• American single roll: 21 in wide × 33 ft long (~56 sq ft)
• American double roll: 21 in wide × 66 ft long (~112 sq ft)
• European roll: 52 cm wide × 10 m long (~5.2 m²)

Tips

• Always buy 1–2 extra rolls for mistakes, future repairs, and dye-lot matching
• Wallpaper with no pattern (solid or random) has zero waste from repeat matching
• Larger pattern repeats (over 12 in / 30 cm) significantly increase waste
• Check whether rolls are sold as single or double rolls — pricing often quotes single rolls but ships in doubles