Calculation method
How each estimate is calculated
Every result comes from the measurements and options you enter. This page explains how the planners round those values, what the diagrams represent and what remains for you to check against the real job.
How measurements are handled
The planners convert measurements to whole millimetres before calculating geometry. Unit conversions happen at the input and display boundaries, so metric and imperial entries follow the same calculation path.
How the tile and pack estimate is rounded
The tile planner counts every tile position that touches the entered room shape. A cut position uses one tile in the estimate because the planner does not assume that another position can reuse its offcut. It then adds the percentage you chose and rounds the result up to complete packs.
packs = ceil(tiles after allowance ÷ tiles in each pack)
tiles in whole packs = packs × tiles in each pack
How wallpaper drops become a roll estimate
Each wall becomes a number of full-width drops. The planner adds the combined trim allowance to the tallest wall and adjusts that drop length for a straight pattern repeat before checking how many drops fit on one roll. Partial-height doors and windows do not reduce the count because material is still needed above or below them. Half-drop calculation is unavailable while the alternating-strip consumption is independently checked against manufacturer guidance.
rolls = ceil(required drops ÷ full drops from one roll)
The estimate does not add a spare roll. Compare the roll dimensions, repeat and match type with the product label before using the result.
How the sheet layout uses available space
The sheet planner sorts rectangular parts and places them into available rectangular spaces while respecting the entered kerf, rotation setting and grain locks. This deterministic method produces an efficient layout, but it does not prove that no other arrangement could use fewer sheets. The result separates part area, rectangular offcuts and material attributed to kerf or residual cut loss.
What the planners leave for you to check
- Measurements, irregular edges, alcoves and transitions at the real site.
- Product dimensions, pack or roll details, batches and pattern direction.
- Any allowance you want for damage, future repairs or unusable material.
- Edge trimming, clamps, cutting order and other fabrication constraints.
- Any installation, structural, safety or regulatory decision.
Reference terms and measurement conventions
Measurement formatting follows the International Bureau of Weights and Measures guidance for SI units. Wallpaper terms follow the industry definitions for random, straight and drop pattern matches. These references explain terminology; they do not validate a particular room or material choice.