Interactive online ISO 2768 general tolerances calculator. Enter a dimension from the drawing and pick the class from the title block — you get the permissible deviation for the linear dimension, the external radius or chamfer height and the angle, and for classes H, K, L also the geometrical tolerances.
Everything is calculated by your browser. The dimensions you type are not sent anywhere — they never reach any server, ours included.
How to read the drawing note: in ISO 2768-mK the lowercase letter (f, m, c, v) is the class from part 1 — linear and angular dimensions, and the capital letter (H, K, L) is the class from part 2 — geometrical tolerances. ISO 2768-m on its own covers part 1 only — part 2 tolerances apply only when the drawing also states their class.
Result
| Feature | Size range | Permissible deviation | Min size | Max size |
|---|
Tables 1–3 of ISO 2768-1:1989. For an angle the range is taken from the length of the shorter side — the calculator uses the size you entered as that length. A general angular tolerance controls only the general orientation of the line, not its form.
Geometrical tolerances — ISO 2768-2
ISO 2768-2 was withdrawn in 2021. It was replaced by ISO 22081:2021, which does not provide ready-made classes H, K, L. The values below apply to drawings that still refer to ISO 2768-2:1989, e.g. with the note ISO 2768-mK.
| Feature | Size range | Tolerance |
|---|
Tables 1–4 of ISO 2768-2:1989. Straightness: range by the length of the line; flatness: by the longer side of the surface or its diameter; perpendicularity: by the shorter of the two sides (the longer one is the datum); symmetry: by the length of the feature; run-out: one value per class.
Not covered by the tables: the standard specifies no general tolerances for cylindricity and coaxiality. Circularity — equal to the diameter tolerance, but not greater than the run-out tolerance; parallelism — the greater of the size tolerance and the flatness / straightness tolerance (ISO 2768-2, clauses 5.1.2, 5.1.3, 5.2.2, 5.2.5).
No ISO 2768-2 class selected — as in the note “ISO 2768-m” without a capital letter. The calculator then gives no general geometrical tolerances.
The table row for the selected class, with the range of the entered size highlighted. “—” is a dash in the standard: there is no general tolerance for that field.
Link to this result — to paste into an e-mail or enquiry:
Where these figures come from and what this calculator does not do
Values from ISO 2768-1:1989 (tables 1–3) and ISO 2768-2:1989 (tables 1–4). Every figure is checked against a second, independent source: the text of the standards (iTeh Standards preview) · DSR Hardware tables · Zatorski tables (PL) · Erich Uhe GmbH and Messtec tables (DE). Read on 20 Oct 2026. Nothing is interpolated between table rows.
- sizes below 0.5 mm — the standard requires the deviations to be stated next to the dimension on the drawing,
- linear sizes over 4000 mm and lengths over 3000 mm in part 2 — the tables end there,
- fields with a dash in the standard — class f over 2000 mm, class v from 0.5 to 3 mm,
- cylindricity and coaxiality — the standard specifies no general tolerances for them.
How to read it
What ISO 2768 in the title block means
A general tolerance applies to every dimension that has no individual tolerance on the drawing. It is stated once — in or near the title block — e.g. ISO 2768-m or ISO 2768-mK.
| Letter | Part | What it covers |
|---|---|---|
| f · m · c · v | ISO 2768-1 | linear dimensions, external radii and chamfer heights, angles — classes: fine, medium, coarse, very coarse |
| H · K · L | ISO 2768-2 | straightness and flatness, perpendicularity, symmetry, circular run-out |
What to watch out for
- Below 0.5 mm there is no general tolerance — the deviations are stated on the drawing next to the dimension.
- A dash in the table means no value: class f does not cover sizes over 2000 up to 4000 mm, and class v does not cover sizes from 0.5 to 3 mm.
- External radii and chamfer heights (broken edges) have their own table (table 2), with values different from linear dimensions.
- Angles are toleranced by the length of the shorter side, and a general angular tolerance controls only the general orientation of the line, not its form.
- ISO 2768-2 was withdrawn in 2021. It was replaced by ISO 22081:2021, which gives no ready-made classes H, K, L — on new drawings geometrical tolerances are stated directly.
- A new single-part edition of ISO 2768 is in preparation (draft ISO/FDIS 2768). This calculator works to ISO 2768-1:1989 — if a drawing refers to the new edition, check its tables.
Have a drawing with tolerances? We turn and mill CNC parts — single pieces and small batches for companies. Send an enquiry. Hole and shaft fits (e.g. H7/g6) can be calculated in our ISO 286 fits calculator, and choosing tolerances is covered in Tolerances in CNC machining.
Sources
Tables and rules: ISO 2768-1:1989 and ISO 2768-2:1989 (text of the standards) ·
DSR
Hardware, “ISO 2768 General Tolerance Standards” ·
Zatorski,
“Tolerancje wymiarowe” (PL) ·
Erich Uhe GmbH,
“Allgemeintoleranzen nach DIN ISO 2768” (DE).
Withdrawal of part 2: foreword of ISO 22081:2021 (“cancels and replaces ISO 2768-2:1989”) ·
K. Petr, “General Geometrical
Tolerances according to ISO 22081”, ICMD 2022.
Read on 20 Oct 2026. Only what two independent sources agree on goes into the
calculator. The wording of the standard prevails.
Prepared by: HARDPOWER, Szczecin, Poland — CNC machining. Technical questions: biuro@hardpower.pl, +48 91 817 28 77.
Tables to ISO 2768-1:1989 and ISO 2768-2:1989 (withdrawn). This calculator is a workshop aid. The wording of the standard prevails.
