A roll of wallpaper advertised with a certain square footage almost never gives you that much usable coverage. The gap between "labeled coverage" and "what you actually get on the wall" comes down to one number most people never think to check: pattern repeat.
What "Pattern Repeat" Means
Pattern repeat is the vertical distance before a wallpaper's design starts over. A small repeat (a few inches) wastes almost nothing. A large repeat — 24 inches or more, common on bold florals or damask-style prints — means every strip has to be cut to line the pattern up with the strip next to it, and the offcuts from that matching process can't be reused.
Straight Match vs Drop Match
In a straight match, the pattern lines up at the same height across every strip — simpler, less wasteful. In a drop match, the pattern is intentionally offset row to row (common on more organic, less geometric designs), which requires extra length per strip to execute correctly. Check which type your paper uses; it's usually printed on the label or product page.
Why the Calculator's Default Is Already Lower Than the Roll Size
This is exactly why the wallpaper calculator's coverage field defaults to 25 square feet even though many rolls are labeled higher — that default already accounts for typical trimming and matching loss. If your specific paper has an unusually large repeat, push that number down further before calculating.
Run your own numbers with the wallpaper calculator, adjusting the usable coverage field to match your paper's actual repeat and match type.