{
  "id": "iso-2768",
  "title": "ISO 2768-1 general tolerances — linear dimensions, radii & chamfers",
  "url": "https://nxtolerance.com/data/iso-2768.json",
  "page": "https://nxtolerance.com/tools/stack-up-calculator/",
  "source": {
    "name": "Engineering tolerance standards reference data",
    "publisher": "SuperNX / nxtolerance.com",
    "standards": "ISO 2768-1:1989, Tables 1 & 2",
    "note": "Values compiled from the published standard tables and cross-checked against multiple independent public references; see the verification log in the source repository.",
    "method": "Permissible deviations are symmetric ±mm per nominal band (lo,hi]; null = class not defined for that band."
  },
  "units": {
    "deviations": "±mm",
    "nominal": "mm"
  },
  "classes": {
    "f": "fine",
    "m": "medium",
    "c": "coarse",
    "v": "very coarse"
  },
  "data": {
    "linear": {
      "bands": [
        [
          0.5,
          3
        ],
        [
          3,
          6
        ],
        [
          6,
          30
        ],
        [
          30,
          120
        ],
        [
          120,
          400
        ],
        [
          400,
          1000
        ],
        [
          1000,
          2000
        ],
        [
          2000,
          4000
        ]
      ],
      "classes": {
        "f": [
          0.05,
          0.05,
          0.1,
          0.15,
          0.2,
          0.3,
          0.5,
          null
        ],
        "m": [
          0.1,
          0.1,
          0.2,
          0.3,
          0.5,
          0.8,
          1.2,
          2
        ],
        "c": [
          0.2,
          0.3,
          0.5,
          0.8,
          1.2,
          2,
          3,
          4
        ],
        "v": [
          null,
          0.5,
          1,
          1.5,
          2.5,
          4,
          6,
          8
        ]
      },
      "note": "Applies to external/internal sizes, diameters, distances and steps. Below 0.5 mm each dimension needs its own tolerance."
    },
    "radiiChamfer": {
      "bands": [
        [
          0.5,
          3
        ],
        [
          3,
          6
        ],
        [
          6,
          null
        ]
      ],
      "classes": {
        "f": [
          0.2,
          0.5,
          1
        ],
        "m": [
          0.2,
          0.5,
          1
        ],
        "c": [
          0.4,
          1,
          2
        ],
        "v": [
          0.4,
          1,
          2
        ]
      }
    }
  },
  "disclaimer": "Engineering reference values for design and education — verify against the current standard revision (ISO 286-1:2010, ISO 2768-1:1989, ASME Y14.5) before issuing production drawings.",
  "license": "Standard reference data. Free to use and cite with attribution to nxtolerance.com.",
  "version": "2026-10-07"
}