{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"drywall"},"result":{"entity_type":"calculator","id":"drywall","calculator_id":"drywall","canonical_url":"https://tttkmbb.com/construction/drywall","name":"Drywall Calculator","title":"Drywall Calculator – Sheets of Plasterboard, Screws and Joint Compound from Wall and Ceiling Area","category":"construction","category_name":"Construction & Home","tool_name":"estimate_drywall_sheets","featured_mcp_tool":false,"description":"Estimates the number of gypsum board sheets for walls (and optionally the ceiling) of a room with a waste allowance, plus screws at about one per square foot and joint compound at the USG rate of 10 gallons per 1,000 ft² of board.","use_when":"You need to order plasterboard/drywall sheets, screws and joint compound for a room or a known wall area.","do_not_use_when":"You need paint or wallpaper quantities for the finished wall (use paint or wallpaper), or metal-stud framing take-offs.","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_length","label":"Room length","type":"number","unit":"m or ft","required":false,"max":1000,"exclusive_min":0,"description":"Room length (m or ft); used with room_width and wall_height when wall_area is not given, and for the ceiling.","example":5},{"name":"room_width","label":"Room width","type":"number","unit":"m or ft","required":false,"max":1000,"exclusive_min":0,"description":"Room width (m or ft).","example":4},{"name":"wall_height","label":"Wall height","type":"number","unit":"m or ft","required":false,"max":100,"exclusive_min":0,"description":"Wall height (m or ft).","example":2.4},{"name":"wall_area","label":"Wall area","type":"number","unit":"m² or ft²","required":false,"exclusive_min":0,"description":"Total wall area to board (m² or ft²); replaces 2 × (length + width) × height when given."},{"name":"include_ceiling","label":"Include ceiling","type":"boolean","required":false,"default":false,"description":"Add the ceiling area (room_length × room_width).","example":false},{"name":"openings_area","label":"Openings to subtract","type":"number","unit":"m² or ft²","required":false,"default":0,"min":0,"description":"Area of large openings (doors, windows) to deduct; small openings are usually not deducted because the cut-outs are waste.","example":0},{"name":"sheet_size","label":"Sheet size","type":"enum","required":false,"values":[{"value":"4x8_ft","label":"4 × 8 ft (32 ft² = 2.973 m²)","aliases":["4x8","1220x2440"]},{"value":"4x12_ft","label":"4 × 12 ft (48 ft² = 4.459 m²)","aliases":["4x12"]},{"value":"1200x2400_mm","label":"1200 × 2400 mm (2.88 m²)","aliases":["1200x2400"]},{"value":"1200x3000_mm","label":"1200 × 3000 mm (3.6 m²)","aliases":["1200x3000"]}],"description":"Board size. Default 1200 × 2400 mm (metric) or 4 × 8 ft (imperial).","example":"1200x2400_mm"},{"name":"waste_percent","label":"Waste allowance","type":"number","unit":"%","required":false,"default":10,"min":0,"max":50,"description":"Extra material for cuts, breakage and offcuts, applied as a multiplier (1 + waste_percent/100). 10 % is typical for rooms with few openings; use 15 % for complex rooms.","example":10}],"outputs":[{"name":"area_m2","label":"Area to board","type":"number","unit":"m²","decimals":2,"description":"Walls (+ ceiling) − openings."},{"name":"area_ft2","label":"Area to board","type":"number","unit":"ft²","decimals":2,"description":"Area in square feet."},{"name":"sheets_needed","label":"Sheets needed","type":"integer","decimals":4,"description":"ceil(area × (1 + waste_percent/100) / sheet_area)."},{"name":"sheet_size_used","label":"Sheet size used","type":"string","decimals":4,"description":"Board size assumed."},{"name":"screws","label":"Screws (approx.)","type":"integer","decimals":4,"description":"About 1 screw per ft² of board (≈ 32 per 4 × 8 sheet at 16 in stud spacing)."},{"name":"joint_compound_liters","label":"Joint compound","type":"number","unit":"L","decimals":1,"description":"Ready-mixed all-purpose compound: 37.8 L per 100 m² of board (USG)."},{"name":"joint_compound_gallons","label":"Joint compound","type":"number","unit":"US gal","decimals":2,"description":"10 gal per 1,000 ft² of board (USG)."},{"name":"compound_pails_4_5_gal","label":"4.5 gal pails","type":"integer","decimals":4,"description":"ceil(gallons / 4.5), the common US pail size (about 17 L)."}],"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_length":{"description":"Room length (m or ft); used with room_width and wall_height when wall_area is not given, and for the ceiling. Unit: m or ft.","type":"number","maximum":1000,"exclusiveMinimum":0,"examples":[5],"x-unit":"m or ft"},"room_width":{"description":"Room width (m or ft). Unit: m or ft.","type":"number","maximum":1000,"exclusiveMinimum":0,"examples":[4],"x-unit":"m or ft"},"wall_height":{"description":"Wall height (m or ft). Unit: m or ft.","type":"number","maximum":100,"exclusiveMinimum":0,"examples":[2.4],"x-unit":"m or ft"},"wall_area":{"description":"Total wall area to board (m² or ft²); replaces 2 × (length + width) × height when given. Unit: m² or ft².","type":"number","exclusiveMinimum":0,"x-unit":"m² or ft²"},"include_ceiling":{"description":"Add the ceiling area (room_length × room_width).","type":"boolean","default":false,"examples":[false]},"openings_area":{"description":"Area of large openings (doors, windows) to deduct; small openings are usually not deducted because the cut-outs are waste. Unit: m² or ft².","type":"number","minimum":0,"default":0,"examples":[0],"x-unit":"m² or ft²"},"sheet_size":{"description":"Board size. Default 1200 × 2400 mm (metric) or 4 × 8 ft (imperial).","type":"string","enum":["4x8_ft","4x12_ft","1200x2400_mm","1200x3000_mm"],"examples":["1200x2400_mm"]},"waste_percent":{"description":"Extra material for cuts, breakage and offcuts, applied as a multiplier (1 + waste_percent/100). 10 % is typical for rooms with few openings; use 15 % for complex rooms. Unit: %.","type":"number","minimum":0,"maximum":50,"default":10,"examples":[10],"x-unit":"%"}},"additionalProperties":false},"output_schema":{"type":"object","properties":{"area_m2":{"description":"Walls (+ ceiling) − openings. Unit: m².","type":"number","x-unit":"m²"},"area_ft2":{"description":"Area in square feet. Unit: ft².","type":"number","x-unit":"ft²"},"sheets_needed":{"description":"ceil(area × (1 + waste_percent/100) / sheet_area).","type":"integer"},"sheet_size_used":{"description":"Board size assumed.","type":"string"},"screws":{"description":"About 1 screw per ft² of board (≈ 32 per 4 × 8 sheet at 16 in stud spacing).","type":"integer"},"joint_compound_liters":{"description":"Ready-mixed all-purpose compound: 37.8 L per 100 m² of board (USG). Unit: L.","type":"number","x-unit":"L"},"joint_compound_gallons":{"description":"10 gal per 1,000 ft² of board (USG). Unit: US gal.","type":"number","x-unit":"US gal"},"compound_pails_4_5_gal":{"description":"ceil(gallons / 4.5), the common US pail size (about 17 L).","type":"integer"}}},"formula":"area = 2 × (room_length + room_width) × wall_height (or wall_area) + room_length × room_width (if include_ceiling) − openings_area; sheets = ceil(area × (1 + waste/100) / sheet_area); screws ≈ area_ft² × 1; compound_gal = area_ft² / 100; pails = ceil(compound_gal / 4.5).","method":"Fastener spacing follows IRC R702.3.5 (screws at 16 in on walls and 12 in on ceilings with 16 in framing), which works out to roughly one screw per square foot. Compound coverage is USG's figure for taping and three-coat finishing of the joints.","sources":[{"name":"USG – Sheetrock Brand All Purpose Joint Compound submittal sheet (≈ 10 gal per 1,000 sq ft of panels)","url":"https://www.usg.com/content/dam/USG_Marketing_Communications/united_states/product_promotional_materials/finished_assets/sheetrock-all-purpose-joint-compound-submittal-J1969.pdf","type":"reference","retrieved_at":"2026-09-23"},{"name":"ICC – 2021 International Residential Code, Chapter 7 Wall Covering (R702.3.5 gypsum board fastening)","url":"https://codes.iccsafe.org/content/IRC2021P2/chapter-7-wall-covering","type":"standard","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":"15 ft × 12 ft × 8 ft room with ceiling, 4 × 8 sheets, 10 % waste","inputs":{"unit_system":"imperial","room_length":15,"room_width":12,"wall_height":8,"include_ceiling":true,"sheet_size":"4x8_ft","waste_percent":10},"expected":{"area_ft2":612,"area_m2":56.86,"sheets_needed":22,"sheet_size_used":"4 × 8 ft","screws":612,"joint_compound_gallons":6.12,"joint_compound_liters":23.2,"compound_pails_4_5_gal":2},"url":"https://tttkmbb.com/api/v1/calculate/drywall?unit_system=imperial&room_length=15&room_width=12&wall_height=8&include_ceiling=true&sheet_size=4x8_ft&waste_percent=10"},{"name":"40 m² of wall, 1200 × 2400 mm boards, 10 % waste","inputs":{"unit_system":"metric","wall_area":40,"waste_percent":10},"expected":{"area_m2":40,"area_ft2":430.56,"sheets_needed":16,"sheet_size_used":"1200 × 2400 mm","screws":431,"joint_compound_liters":16.3,"joint_compound_gallons":4.31,"compound_pails_4_5_gal":1},"url":"https://tttkmbb.com/api/v1/calculate/drywall?unit_system=metric&wall_area=40&waste_percent=10"}],"faq":[{"q":"Should I subtract doors and windows?","a":"Usually not for standard openings: the cut-out pieces are rarely reusable, so most estimators ignore openings under about 2 m² and only deduct large ones via openings_area."},{"q":"Which sheet size should I choose?","a":"Use the longest sheets you can handle: 4 × 12 ft or 1200 × 3000 mm sheets reduce the number of joints to tape; 4 × 8 ft and 1200 × 2400 mm are the common DIY sizes."},{"q":"Is tape included?","a":"No. Joint tape is roughly 37 m per 100 m² (370 ft per 1,000 ft²) of board; corner bead is the sum of the outside-corner lengths."}],"tags":["drywall calculator","plasterboard sheets","gypsum board","drywall screws","joint compound","sheetrock"],"related":[{"calculator_id":"paint","reason":"Paint for the finished boards."},{"calculator_id":"wallpaper","reason":"Paper for the finished boards."}],"links":{"html":"https://tttkmbb.com/construction/drywall","markdown":"https://tttkmbb.com/construction/drywall.md","json":"https://tttkmbb.com/construction/drywall.json","api":"https://tttkmbb.com/api/v1/calculate/drywall","schema":"https://tttkmbb.com/api/v1/calculators/drywall","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-23"},"timestamp":"2026-09-23T23:23:14Z"}