{
  "tool": "paint",
  "version": "1.0.0",
  "inputs": {
    "room_length_cm": 400,
    "room_width_cm": 300,
    "ceiling_height_cm": 240,
    "surfaces": "walls",
    "feature_wall": "length",
    "doors": 1,
    "windows": 1,
    "door_width_cm": 76.2,
    "door_height_cm": 198.1,
    "window_width_cm": 120,
    "window_height_cm": 120,
    "coats": 2,
    "paint": "matt",
    "coverage_m2_per_l": 13,
    "new_plaster": "no",
    "spare_pct": 10
  },
  "answer": {
    "paint_l": 4.715,
    "with_spare_l": 5.187,
    "tins": [
      {
        "size_l": 5,
        "count": 1
      },
      {
        "size_l": 2.5,
        "count": 1
      }
    ],
    "tins_text": "1 × 5 l + 1 × 2.5 l",
    "in_tins_l": 7.5,
    "tins_without_spare": [
      {
        "size_l": 5,
        "count": 1
      }
    ],
    "tins_without_spare_text": "1 × 5 l",
    "area": {
      "walls_gross_m2": 33.6,
      "openings_m2": 2.95,
      "walls_net_m2": 30.65,
      "ceiling_m2": 0,
      "total_m2": 30.65
    },
    "mist_coat": null
  },
  "summary": "To paint the walls (30.7 m²) with 2 coats at 13 m² a litre you need 4.7 litres, 5.2 with 10% spare: buy 1 × 5 l + 1 × 2.5 l.",
  "working": [
    "Walls: 2 × (4 m + 3 m) × 2.4 m = 33.6 m²",
    "Less 1 door at 1.51 m² and 1 window at 1.44 m²: −2.95 m²",
    "Area to paint: 30.7 m²",
    "30.7 m² × 2 coats ÷ 13 m² per litre = 4.7 l",
    "Plus 10% spare = 5.2 l",
    "Tins: 1 × 5 l + 1 × 2.5 l = 7.5 l"
  ],
  "notes": [],
  "sources": [
    {
      "label": "B&Q, Dulux Walls & Ceilings matt 2.5 l (£25, £10/l)",
      "url": "https://www.diy.com/departments/dulux-walls-ceilings-egyptian-cotton-matt-emulsion-paint-2-5l/126241_BQ.prd",
      "checked": "2026-10-31"
    },
    {
      "label": "B&Q, Dulux Walls & Ceilings matt 5 l (£36, £7.20/l)",
      "url": "https://www.diy.com/departments/dulux-walls-ceilings-ivory-lace-matt-emulsion-paint-5l/126289_BQ.prd",
      "checked": "2026-10-31"
    },
    {
      "label": "Screwfix, Dulux Pure Brilliant White silk emulsion 2.5 l (13 m²/l)",
      "url": "https://www.screwfix.com/p/dulux-2-5ltr-pure-brilliant-white-silk-emulsion-paint/4503V",
      "checked": "2026-10-31"
    },
    {
      "label": "B&Q, Wall painting calculator (\"at least 10% extra\")",
      "url": "https://www.diy.com/ideas-advice/calculators/wall-painting-calculator",
      "checked": "2026-10-31"
    },
    {
      "label": "Homebase, Paint calculator (optional 10% buffer)",
      "url": "https://www.homebase.co.uk/paint-decorating/paint-calculator/c/h70",
      "checked": "2026-10-31"
    },
    {
      "label": "Dulux UK, How much paint do you need? (1 l for a 2.5 m feature wall; 2.5 l for a 2 × 2 m room; 5 l for a 4 × 4 m room)",
      "url": "https://www.dulux.co.uk/en/expert-help/how-much-paint-do-you-need",
      "checked": "2026-10-31"
    },
    {
      "label": "Howarth Timber (Green, 14 Sep 2026), UK door sizes",
      "url": "https://www.howarth-timber.co.uk/inspiration-advice/uk-door-sizes",
      "checked": "2026-10-31"
    }
  ],
  "page_url": "https://snuug.app/tools/paint",
  "snuug": "Snuug is an iPhone app that rebuilds your room in 3D, to within about 3% of its real size, so you can redesign it and see what fits before you buy a thing. Not yet on the App Store (31 October 2026)."
}