{
 "version": "2026-10-20",
 "license": "Dimension sheets are written by Xem Studio from the cited sources and are free to use (CC BY 4.0, attribute 'Xem Studio'). Linked files belong to their publishers under the license shown; Xem Studio does not host them. 'license_verified: false' means the license shown is from memory or the publisher's page as last read and should be confirmed at the link before commercial use.",
 "slug": "a21-light-bulb",
 "name": "A21 light bulb (E26 base)",
 "kind": "modern",
 "category": "Everyday objects",
 "group": "Light bulbs",
 "year": null,
 "question": "What size is an A21 light bulb?",
 "tags": [
  "light bulb",
  "lamp",
  "a21"
 ],
 "aliases": [
  "a21 bulb size",
  "a21 dimensions",
  "a21 light bulb dimensions"
 ],
 "overall_mm": {
  "length": 78,
  "width": 78,
  "height": 140
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/a21-light-bulb/",
 "sheet_txt": "https://xemstudio.com/objects/a21-light-bulb/sheet.txt",
 "sheet": {
  "basis": "Philips product datasheet (Philips 16A21/PER/830/P/E26/DIM)",
  "overall_mm": {
   "length": 78,
   "width": 78,
   "height": 140
  },
  "notes": [
   "A21: Ø78 mm, 140 mm maximum overall length, E26 base — figures from the Philips 16A21/PER/830/P/E26/DIM datasheet.",
   "The shape code gives the diameter in eighths of an inch (A21); the ANSI C78 envelope limits are paywalled, so a typical current product is quoted. Other brands differ by a few mm in length.",
   "The file is a cylinder envelope Ø × MOL (the bulb fits inside it)."
  ],
  "table": {
   "columns": [
    "dimension",
    "value"
   ],
   "rows": [
    [
     "diameter",
     "78 mm (3.07 in)"
    ],
    [
     "max overall length",
     "140 mm (5.51 in)"
    ],
    [
     "base",
     "E26"
    ],
    [
     "reference product",
     "Philips 16A21/PER/830/P/E26/DIM"
    ]
   ]
  }
 },
 "sheet_text": "A21 light bulb (E26 base) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/a21-light-bulb/  (CC BY 4.0)\nBasis: Philips product datasheet (Philips 16A21/PER/830/P/E26/DIM)\nCatalog version: 2026-10-20\n\nOverall (mm): length 78, width 78, height 140\n- A21: Ø78 mm, 140 mm maximum overall length, E26 base — figures from the Philips 16A21/PER/830/P/E26/DIM datasheet.\n- The shape code gives the diameter in eighths of an inch (A21); the ANSI C78 envelope limits are paywalled, so a typical current product is quoted. Other brands differ by a few mm in length.\n- The file is a cylinder envelope Ø × MOL (the bulb fits inside it).\n\ndimension  value\ndiameter  78 mm (3.07 in)\nmax overall length  140 mm (5.51 in)\nbase  E26\nreference product  Philips 16A21/PER/830/P/E26/DIM\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Philips: Philips 16A21/PER/830/P/E26/DIM datasheet — web — Publisher's page; dimensions are facts — https://www.assets.lighting.philips.com/is/content/PhilipsLighting/fp929001836904-pss-en_us\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/a21-light-bulb/index.json\nAPI: https://xemstudio.com/api/geometry?object=a21-light-bulb\n",
 "sources": [
  {
   "publisher": "Philips",
   "title": "Philips 16A21/PER/830/P/E26/DIM datasheet",
   "url": "https://www.assets.lighting.philips.com/is/content/PhilipsLighting/fp929001836904-pss-en_us",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "a19-light-bulb",
  "br30-light-bulb",
  "br40-light-bulb",
  "par30l-light-bulb",
  "par38-light-bulb",
  "g25-light-bulb",
  "mr16-light-bulb",
  "gu10-par16-light-bulb"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [],
 "faq": [
  {
   "q": "How big is an A21 bulb?",
   "a": "About Ø78 × 140 mm (reference product)."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "a21-light-bulb-envelope",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/a21-light-bulb/a21-light-bulb-envelope.step",
   "stl": "https://xemstudio.com/files/hardware/a21-light-bulb/a21-light-bulb-envelope.stl",
   "note": "Envelope Ø78 × 140 mm"
  }
 ],
 "markdown": "https://xemstudio.com/objects/a21-light-bulb/index.md"
}