Wallpaper Calculator

Professional decorators and DIY enthusiasts use this tool to determine the exact number of wallpaper rolls required for a room. Accuracy is paramount here because underestimating leads to batch mismatches where subsequent rolls differ slightly in color. Overestimating results in unnecessary expense and leftover material that cannot be returned. This calculator accounts for complex variables like pattern repeats and match types which significantly impact the total length needed per strip.

Standard area calculations fail when dealing with patterned paper. A large pattern repeat or a half-drop match forces specific cutting points to maintain visual continuity. This tool calculates the effective strip length by factoring in the vertical repeat and the type of match. It ensures that the design aligns perfectly across seams while quantifying the exact waste generated by these adjustments.

The core logic determines the number of strips required and the adjusted length of each strip to accommodate pattern matching. The number of strips N is derived from the room perimeter and roll width.

Where P is room perimeter and O is the width of openings (doors/windows). The adjusted strip length L_adj depends on the pattern repeat R.

For Drop Match patterns, an additional offset R/2 is often required every other strip. Total rolls T is calculated by fitting these strips into the roll length L_roll.