ISO 2768 General Tolerance Lookup
Enter a nominal size and a tolerance class to see the general tolerance ISO 2768-1 allows on a dimension that carries no tolerance of its own. The lookup covers linear dimensions, external radii and chamfer heights, and angular dimensions, and returns the size band, the permissible deviation and the resulting limits in millimetres and inches.
Calculator Setup
Size as written on the drawing, in millimetres.
Enter a size and choose a class to see the result.
| f (fine) | m (medium) | c (coarse) | v (very coarse) |
|---|---|---|---|
How to read the result
- Size band: the table row your size falls in. A size that sits on a band edge reads from the lower row, so 30 mm uses “over 6 up to 30 mm”.
- Permissible deviation: the same amount above and below nominal. On a 50 mm dimension in class m, ±0.3 mm gives limits of 49.7 mm and 50.3 mm.
- Inch values: converted at 1 in = 25.4 mm and rounded to three decimals. The millimetre values are the ones the standard states.
- Angular dimensions: the band comes from the length of the shorter side of the angle, not from the size of the angle.
- No value: in the linear table, class f has no row over 2000 up to 4000 mm and class v has none for 0.5 up to 3 mm. Below 0.5 mm, Note 1 of ISO 2768-1 asks for the deviation to be written next to the dimension.
Where the values come from
The linear, radius and chamfer, and angular values follow the tables of ISO 2768-1:1989, checked against two independent reproductions of the standard. ISO last reviewed and confirmed ISO 2768-1:1989 in 2022 and lists a revised ISO 2768 under development.
- The capital letter in a note such as ISO 2768-mK comes from ISO 2768-2:1989, which ISO withdrew on 2021-02-04 and revised as ISO 22081:2021. This lookup covers Part 1 only.
- The linear table ends at 4000 mm. The radius and chamfer table ends with an open “over 6 mm” row, and the angular table with an open “over 400 mm” row.
For design release, check the values against the edition of ISO 2768-1 named on your drawing.
Need Custom Machining?
Have a drawing with a general tolerance note? Send it with your quantities and material for a quote on made-to-drawing metal parts.
Request a QuoteRESOURCES
- ISO 2768 table on the CNC machining knowledge library
- Tolerance limit converter for any ± tolerance in either unit
- ISO 2768 title block note decoder for notes such as ISO 2768-mK
- ISO 2768 class finder for the class that covers a tolerance you need
