Wallpaper Roll Calculator
Calculate wallpaper drops and rolls from total wall width, wall height, roll size and pattern repeat. The drop-based method accounts for one of the biggest differences between wallpaper and simple area calculators.
Wallpaper and wall inputs
Wallpaper roll requirement
Why wallpaper needs a drop calculation
Wallpaper is normally installed as vertical lengths. The number of drops depends on the roll width, while the number of usable drops per roll depends on the roll length and required drop length.
Drop length with trim = wall height + top/bottom allowance
Patterned drop = ceiling(drop ÷ repeat) × repeat
Drops per roll = floor(roll length ÷ patterned drop)
Rolls = ceiling(drops required × (1 + waste) ÷ drops per roll)
Worked example
With 12 m of wall width and 0.53 m wallpaper width, 23 vertical drops are required. If the wall is 2.7 m high with 0.10 m trimming and a 0.32 m pattern repeat, each drop is rounded to the next matching repeat before determining how many drops fit inside a 10.05 m roll.
Why pattern repeat matters
Two wallpapers with identical roll dimensions can produce different roll counts because their pattern-repeat increments consume different amounts of material for each drop.
Important matching details
Directional designs, offset repeats and manufacturer's match codes can change the actual cutting strategy. Use the product's instructions when a project requires exact pattern alignment.
Limitations
The calculator assumes consistent wall height and a single wallpaper roll specification. It does not model corners, doors, windows or reusable offcuts on a piece-by-piece basis.
Frequently Asked Questions
Why can't I just use wall area?
Because roll width, drop length and pattern repeat determine how the wallpaper is actually cut.
Does pattern repeat increase rolls?
It can.
Should doors and windows be deducted?
Area can be reduced, but their locations still influence drop cutting.
Can I enter zero repeat?
Yes, for non-patterned wallpaper.