{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"wallpaper"},"result":{"entity_type":"calculator","id":"wallpaper","calculator_id":"wallpaper","canonical_url":"https://tttkmbb.com/construction/wallpaper","name":"Wallpaper Calculator","title":"Wallpaper Calculator – Rolls Needed from Perimeter, Height, Roll Size and Pattern Repeat","category":"construction","category_name":"Construction & Home","tool_name":"estimate_wallpaper_rolls","featured_mcp_tool":false,"description":"Estimates wallpaper rolls by the strip method: the strip length is the wall height plus 10 cm trim, rounded up to a whole pattern repeat; whole strips per roll are counted, door and window areas are deducted and the strips are converted to rolls.","use_when":"You need to know how many rolls of wallpaper to buy for a room from its perimeter (or wall area), height and the roll dimensions, with or without a pattern repeat.","do_not_use_when":"You are painting (use paint) or boarding (use drywall) the walls, or the paper is a mural sold by the panel.","inputs":[{"name":"unit_system","label":"Unit system","type":"enum","required":false,"default":"metric","values":[{"value":"metric","label":"Metric (m, cm, mm, m²)","aliases":["si","metres","meters"]},{"value":"imperial","label":"Imperial / US customary (ft, in, ft²)","aliases":["us","feet","inches"]}],"description":"Unit system of the length inputs (metric: m / cm / mm; imperial: ft / in). Outputs are reported in both systems.","example":"metric"},{"name":"room_perimeter","label":"Room perimeter","type":"number","unit":"m or ft","required":false,"max":10000,"exclusive_min":0,"description":"Total length of the walls to paper (m or ft), e.g. 2 × (length + width). Alternatively give wall_area.","example":16},{"name":"wall_height","label":"Wall height","type":"number","unit":"m or ft","required":true,"max":100,"exclusive_min":0,"description":"Height to paper (m or ft); 10 cm (4 in) is added per strip for trimming.","example":2.4},{"name":"wall_area","label":"Gross wall area","type":"number","unit":"m² or ft²","required":false,"exclusive_min":0,"description":"Gross wall area before openings (m² or ft²); used instead of room_perimeter × wall_height when given."},{"name":"doors","label":"Doors","type":"integer","required":false,"default":1,"min":0,"max":100,"description":"Number of doors; 1.9 m² (20.5 ft²) is deducted per door.","example":1},{"name":"windows","label":"Windows","type":"integer","required":false,"default":1,"min":0,"max":100,"description":"Number of windows; 1.4 m² (15.1 ft²) is deducted per window.","example":1},{"name":"roll_width","label":"Roll width","type":"number","unit":"m or ft","required":false,"max":10,"exclusive_min":0,"description":"Roll width. Default 0.53 m (metric, European roll) or 2.25 ft = 27 in (imperial, American roll).","example":0.53},{"name":"roll_length","label":"Roll length","type":"number","unit":"m or ft","required":false,"max":200,"exclusive_min":0,"description":"Roll length. Default 10.05 m (metric) or 27 ft (imperial).","example":10.05},{"name":"pattern_repeat","label":"Pattern repeat","type":"number","unit":"cm or in","required":false,"default":0,"min":0,"max":500,"description":"Vertical pattern repeat printed on the label (cm or in); 0 for plain or free-match paper. Each strip is rounded up to a whole number of repeats.","example":0}],"outputs":[{"name":"gross_wall_area_m2","label":"Gross wall area","type":"number","unit":"m²","decimals":2,"description":"perimeter × height (or wall_area)."},{"name":"net_wall_area_m2","label":"Net wall area","type":"number","unit":"m²","decimals":2,"description":"Gross area minus door and window deductions."},{"name":"strip_length_m","label":"Strip length","type":"number","unit":"m","decimals":3,"description":"Height + 0.10 m trim, rounded up to whole pattern repeats."},{"name":"strip_length_ft","label":"Strip length","type":"number","unit":"ft","decimals":2,"description":"Strip length in feet."},{"name":"strips_per_roll","label":"Strips per roll","type":"integer","decimals":4,"description":"floor(roll_length / strip_length)."},{"name":"strips_needed","label":"Strips needed","type":"integer","decimals":4,"description":"ceil(net_wall_area / (roll_width × wall_height))."},{"name":"rolls_needed","label":"Rolls needed","type":"integer","decimals":4,"description":"ceil(strips_needed / strips_per_roll)."},{"name":"roll_size_used","label":"Roll size used","type":"string","decimals":4,"description":"Roll width × length assumed."}],"input_schema":{"type":"object","properties":{"unit_system":{"description":"Unit system of the length inputs (metric: m / cm / mm; imperial: ft / in). Outputs are reported in both systems.","type":"string","enum":["metric","imperial"],"default":"metric","examples":["metric"]},"room_perimeter":{"description":"Total length of the walls to paper (m or ft), e.g. 2 × (length + width). Alternatively give wall_area. Unit: m or ft.","type":"number","maximum":10000,"exclusiveMinimum":0,"examples":[16],"x-unit":"m or ft"},"wall_height":{"description":"Height to paper (m or ft); 10 cm (4 in) is added per strip for trimming. Unit: m or ft.","type":"number","maximum":100,"exclusiveMinimum":0,"examples":[2.4],"x-unit":"m or ft"},"wall_area":{"description":"Gross wall area before openings (m² or ft²); used instead of room_perimeter × wall_height when given. Unit: m² or ft².","type":"number","exclusiveMinimum":0,"x-unit":"m² or ft²"},"doors":{"description":"Number of doors; 1.9 m² (20.5 ft²) is deducted per door.","type":"integer","minimum":0,"maximum":100,"default":1,"examples":[1]},"windows":{"description":"Number of windows; 1.4 m² (15.1 ft²) is deducted per window.","type":"integer","minimum":0,"maximum":100,"default":1,"examples":[1]},"roll_width":{"description":"Roll width. Default 0.53 m (metric, European roll) or 2.25 ft = 27 in (imperial, American roll). Unit: m or ft.","type":"number","maximum":10,"exclusiveMinimum":0,"examples":[0.53],"x-unit":"m or ft"},"roll_length":{"description":"Roll length. Default 10.05 m (metric) or 27 ft (imperial). Unit: m or ft.","type":"number","maximum":200,"exclusiveMinimum":0,"examples":[10.05],"x-unit":"m or ft"},"pattern_repeat":{"description":"Vertical pattern repeat printed on the label (cm or in); 0 for plain or free-match paper. Each strip is rounded up to a whole number of repeats. Unit: cm or in.","type":"number","minimum":0,"maximum":500,"default":0,"examples":[0],"x-unit":"cm or in"}},"additionalProperties":false,"required":["wall_height"]},"output_schema":{"type":"object","properties":{"gross_wall_area_m2":{"description":"perimeter × height (or wall_area). Unit: m².","type":"number","x-unit":"m²"},"net_wall_area_m2":{"description":"Gross area minus door and window deductions. Unit: m².","type":"number","x-unit":"m²"},"strip_length_m":{"description":"Height + 0.10 m trim, rounded up to whole pattern repeats. Unit: m.","type":"number","x-unit":"m"},"strip_length_ft":{"description":"Strip length in feet. Unit: ft.","type":"number","x-unit":"ft"},"strips_per_roll":{"description":"floor(roll_length / strip_length).","type":"integer"},"strips_needed":{"description":"ceil(net_wall_area / (roll_width × wall_height)).","type":"integer"},"rolls_needed":{"description":"ceil(strips_needed / strips_per_roll).","type":"integer"},"roll_size_used":{"description":"Roll width × length assumed.","type":"string"}}},"formula":"strip = wall_height + 0.10 m, rounded up to a multiple of pattern_repeat; strips_per_roll = floor(roll_length / strip); net_area = perimeter × height − 1.9 m² × doors − 1.4 m² × windows; strips_needed = ceil(net_area / (roll_width × wall_height)); rolls = ceil(strips_needed / strips_per_roll).","method":"Rounding each strip up to a whole repeat is the standard allowance for pattern matching; drop (offset) matches can waste up to half a repeat more per strip. Buy all rolls from the same batch number.","sources":[{"name":"Wikipedia – Wallpaper (roll sizes, pattern repeat)","url":"https://en.wikipedia.org/wiki/Wallpaper","type":"reference","retrieved_at":"2026-09-23"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"16 m perimeter, 2.4 m high, 1 door, 1 window, plain 0.53 × 10.05 m rolls","inputs":{"unit_system":"metric","room_perimeter":16,"wall_height":2.4,"doors":1,"windows":1},"expected":{"gross_wall_area_m2":38.4,"net_wall_area_m2":35.1,"strip_length_m":2.5,"strips_per_roll":4,"strips_needed":28,"rolls_needed":7,"roll_size_used":"0.53 m × 10.05 m"},"url":"https://tttkmbb.com/api/v1/calculate/wallpaper?unit_system=metric&room_perimeter=16&wall_height=2.4&doors=1&windows=1"},{"name":"48 ft perimeter, 8 ft high, 2 doors, 2 windows, 24 in repeat, 27 in × 27 ft rolls","inputs":{"unit_system":"imperial","room_perimeter":48,"wall_height":8,"doors":2,"windows":2,"pattern_repeat":24},"expected":{"gross_wall_area_m2":35.67,"net_wall_area_m2":29.07,"strip_length_ft":10,"strips_per_roll":2,"strips_needed":18,"rolls_needed":9},"url":"https://tttkmbb.com/api/v1/calculate/wallpaper?unit_system=imperial&room_perimeter=48&wall_height=8&doors=2&windows=2&pattern_repeat=24"}],"faq":[{"q":"Should I buy a spare roll?","a":"Usually yes: one extra roll from the same batch covers mistakes and future repairs, because colours differ slightly between batches."},{"q":"Why does a pattern repeat need more rolls?","a":"Each strip must start at the same point of the pattern, so it is cut to a whole number of repeats; a 64 cm repeat on a 2.5 m strip means cutting 2.56 m, which reduces the whole strips per 10.05 m roll from 4 to 3."}],"tags":["wallpaper calculator","rolls of wallpaper","pattern repeat","how many rolls","wall covering"],"related":[{"calculator_id":"paint","reason":"Paint instead of paper for the same walls."},{"calculator_id":"drywall","reason":"Board the walls before decorating."}],"links":{"html":"https://tttkmbb.com/construction/wallpaper","markdown":"https://tttkmbb.com/construction/wallpaper.md","json":"https://tttkmbb.com/construction/wallpaper.json","api":"https://tttkmbb.com/api/v1/calculate/wallpaper","schema":"https://tttkmbb.com/api/v1/calculators/wallpaper","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-23"},"timestamp":"2026-09-23T23:25:35Z","next_actions":[{"tool":"run_calculator","calculator_id":"wallpaper","reason":"Run Wallpaper Calculator with the inputs above."}],"links":{"markdown":"https://tttkmbb.com/construction/wallpaper.md"}}