ISO 2768 general tolerances

General linear tolerances per ISO 2768-1 (class f, m, c, v) — the tolerance for dimensions without an individual note on the drawing.

Size range (mm)fmcv
0,5–3±0.05±0.1±0.2±—
3–6±0.05±0.1±0.3±0.5
6–30±0.1±0.2±0.5±1.0
30–120±0.15±0.3±0.8±1.5
120–400±0.2±0.5±1.2±2.5
400–1000±0.3±0.8±2.0±4.0
1000–2000±0.5±1.2±3.0±6.0
2000–4000±—±2.0±4.0±8.0
Class
m
m · medium
ISO 2768-1 — applies to dimensions without an individual tolerance on the drawing. Values are ± in mm.

What does ISO 2768 cover?

ISO 2768-1 defines general tolerances for linear and angular dimensions that carry no individual tolerance on the drawing. You pick one class for the whole drawing — f (fine), m (medium), c (coarse) or v (very coarse) — and it applies to every "free" dimension. The larger the dimension, the wider the tolerance. Critical dimensions always get their own tighter tolerance.

Frequently asked questions

What does ISO 2768-mK mean?
The first letter is the class for linear dimensions (2768-1: f/m/c/v), the second capital letter the class for geometric tolerances (2768-2: H/K/L).
Which class is used most?
Class m (medium) is common for most machined parts. f (fine) for more precise work, c/v for coarser sheet and welded work.
Does it apply to holes and shafts?
For general dimensions yes. For fits between shaft and hole use ISO 286 (H7/g6 etc.), not ISO 2768.
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