Calculator
Choose a mode, then enter dimensions, roll size, and pattern settings.
Example data table
Use these sample values to test the calculator.
| Scenario | Room (L×W×H) | Roll (W×L) | Repeat | Match | Openings | Waste | Expected result |
|---|---|---|---|---|---|---|---|
| Potting shed | 3.0×2.5×2.4 m | 0.53×10 m | 64 cm | Straight | 1.2 m² | 10% | Shows rolls, strips, and drop length |
| Garden office feature wall | Total width 4.2 m, height 2.6 m | 0.53×10.05 m | 53 cm | Half drop | 0.6 m² | 12% | Higher drop length, fewer drops per roll |
| Utility nook paneling | 2.2×1.8×2.3 m, 65% height | 0.53×10 m | 0 | No match | 0.8 m² | 7% | Lower material due to partial height |
Formula used
1) Wall width to cover
- Perimeter (room mode) = 2 × (Length + Width)
- Total wall width (manual mode) = your entered sum
2) Base drop length
- BaseDrop = EffectiveHeight + TrimAllowance
- EffectiveHeight = WallHeight × (Coverage% ÷ 100)
3) Pattern-adjusted drop length
- No match: Drop = BaseDrop
- Straight match: Drop = ceil(BaseDrop ÷ Repeat) × Repeat
- Half drop: Drop = ceil((BaseDrop + Repeat/2) ÷ Repeat) × Repeat
4) Drops needed
- DropsNeeded = ceil(TotalWidth ÷ RollWidth) + ExtraStrips
- Openings removal is estimated by area: OpeningDropEquiv = OpeningsArea ÷ (RollWidth × EffectiveHeight)
- DropsAfterOpenings ≈ ceil(DropsNeeded − OpeningDropEquiv)
5) Rolls required
- DropsWithWaste = ceil(DropsAfterOpenings × (1 + Waste%))
- DropsPerRoll = floor(RollLength ÷ Drop)
- Rolls = ceil(DropsWithWaste ÷ DropsPerRoll)
How to use this calculator
- Pick Room perimeter for a full room, or Total wall width for custom walls.
- Enter your wall height and set coverage height if not full height.
- Enter roll width and roll length from the product label.
- Enter the pattern repeat and choose match type from the label.
- Add openings area for doors and windows, plus a sensible waste %.
- Click Calculate, then download CSV/PDF for your records.
Why pattern repeat matters in garden-friendly interiors
Wallpaper in potting sheds, mudrooms, and indoor garden corners sees humidity swings, splashes, and strong task lighting. If the repeat is ignored, leaves and trellis lines drift at seams and the finish looks patchy. The calculator rounds each cut to the repeat and match type so every drop starts on the same motif point. That reduces re-cuts and helps you order the right number of rolls.
Measuring walls around benches, sinks, and shelving
Garden workspaces are rarely perfect rectangles. Measure total wall width you will cover, then enter openings area for doors, windows, or large glazed panels. For full-room wrapping, room mode uses the perimeter automatically. For wall sections between shelving uprights, measure each span and add them. If you are papering only above a backsplash or beadboard, lower the coverage percentage to your finish line and keep trim allowance for uneven floors.
Choosing match type for botanical and geometric repeats
Product labels usually specify straight match, half drop, or no match. Straight match keeps motifs aligned across strips and often wastes less. Half drop shifts the design by half a repeat, which can soften seam visibility in dense foliage but needs extra allowance per drop. If the label is unclear, test two offcuts side by side and confirm the seam alignment before purchasing.
Waste planning for repairs, corners, and trimming
A controlled waste percentage prevents last-minute shortfalls. Corners, switches, and trimming consume extra length, especially on walls that are not plumb. In garden-adjacent rooms, it is wise to keep spare material for scuffs or moisture marks. Use higher waste for big repeats, half drop, textured papers, or first-time installs, and add extra strips for tricky returns. Consider one extra roll when matching dye lots matters in bright light.
Reading roll labels and converting units correctly
Roll width and length may be in meters or inches, while repeat can be in centimeters or millimeters. Unit mix-ups are a common cause of under-ordering. Choose the correct units for room size, roll size, and repeat, and let the calculator convert everything consistently before computing drops per roll. Double-check whether the repeat includes border bands, and remeasure if the product is imported.
FAQs
1) What does “pattern repeat” mean?
It is the vertical distance before the design starts again. Larger repeats require longer cuts so the pattern can line up at seams, which can reduce the number of drops you get from each roll.
2) When should I choose half drop match?
Choose half drop when the product label specifies it or when the design shifts by half a repeat between adjacent strips. It helps align motifs but typically increases length allowance and can raise roll count.
3) Can I subtract doors and windows accurately?
You can estimate by entering total openings area. This approximates the number of drops saved based on roll width and covered height. For highly segmented walls, keep waste a bit higher to stay safe.
4) Why does trim allowance matter?
Walls are rarely perfectly plumb and ceilings can wave. Trim allowance adds a small buffer to each drop so you can slide the strip into position, then trim cleanly at the top and bottom.
5) What if my roll label uses inches but my room is in meters?
Set your room unit to meters and your roll and repeat units to inches. The calculator converts all values consistently, preventing unit-mismatch mistakes that often cause under-ordering.
6) How much waste should I allow?
Common ranges are 5–15%. Use the lower end for simple, no-match papers on square rooms. Use the higher end for big repeats, half drop, many corners, or if you want spare material for repairs.