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Wallpaper Calculator

The pattern repeat decides how many rolls. So does this.

Wallpaper estimates go wrong on the pattern repeat, not the wall area. A double roll covers ~56 square feet before matching — but a straight match costs 10% of that yield and a drop match 15%. This calculator measures your room, deducts full-size openings, applies the repeat factor, and rounds to whole double rolls from the same dye lot.

Why people use this

DIY wallpaperers use this because the pattern repeat — not the wall area — decides the roll count, and the label math (straight vs drop match) is exactly what big-box estimators skip. The same-dye-lot warning has saved more walls than any calculator feature.

How it works

1. Enter room length, width, and wall height.
2. Count full-size doors and windows to deduct.
3. Pick the pattern match type from the wallpaper label.
4. Read the double-roll count and cost at your roll price.

Common questions

How much wallpaper does a 12×14 room need?

Walls: 2×(14+12)×9 ft = 468 sq ft, minus a door and two windows ≈ 417 sq ft. With a drop-match pattern (56 ÷ 1.15 ≈ 49 usable sq ft per double roll) that is 9 double rolls. No-match paper would need 8.

Why buy from the same dye lot?

Color varies subtly between production runs — visible as stripes at the seams once hung. Every roll on one wall should share a lot number; buying the full count up front (plus one spare for repairs) is the only reliable way.

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