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Linear and angular dimensions (ISO 2768-1)

Title-block tolerance class for dimensions without individual tolerances. Choose the class and enter a dimension.

Tolerance classNominal size (mm)Shorter leg length (mm, for angle)

Linear size: ±0,3 mm
Radius / chamfer: ±1 mm
Angular size: ±0°30'

STANDARD UNDER REVISION

Validity: Tables 1-3, linear/angular sizes without individual tolerances

Assumptions: A second edition of ISO 2768-1 is under publication at ISO and is expected to replace this 1989 edition; values below are the 1989 text, still published at the time of writing.

Source details

ISO 2768-1:1989 · Verify

Checked 2026-09-17

Size (mm)	f	m	c	v
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
>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	±4
>1000 – 2000	±0,5	±1,2	±3	±6
>2000 – 4000	—	±2	±4	±8

ISO 2768-1 Table 1, permissible deviation of linear sizes (mm). Active class: m.

Radius / chamfer (mm)	f	m	c	v
0,5 – 3	±0,2	±0,2	±0,4	±0,4
>3 – 6	±0,5	±0,5	±1	±1
>6	±1	±1	±2	±2

ISO 2768-1 Table 2.

Leg (mm)	f	m	c	v
≤10	±1°	±1°	±1°30'	±3°
>10 – 50	±0°30'	±0°30'	±1°	±2°
>50 – 120	±0°20'	±0°20'	±0°30'	±1°
>120 – 400	±0°10'	±0°10'	±0°15'	±0°30'
>400	±0°05'	±0°05'	±0°10'	±0°20'

ISO 2768-1 Table 3, based on the length of the shorter leg of the angle.

Geometric tolerances (ISO 2768-2:1989 — withdrawn)

Straightness/flatness, perpendicularity, symmetry and circular run-out without individual indication — classes H, K, L.

These values are the total width of the tolerance zone, not a ± deviation — a flatness of 0.2 mm means the whole surface must lie within a 0.2 mm thick zone, not ±0.2 mm around a nominal value.

ClassNominal length (mm)

Straightness / flatness: 0,2 mm
Perpendicularity: 0,4 mm
Symmetry: 0,6 mm
Circular run-out (length-independent): 0,2 mm

LEGACY / WITHDRAWN STANDARD

Validity: Tables 4-7, geometric tolerance classes H/K/L

Assumptions: ISO 2768-2:1989 is withdrawn. ISO 22081:2021 is the current general geometrical specifications framework that replaces it — use these H/K/L classes only to interpret existing drawings, not for new designs.

Source details

ISO 2768-2:1989 · Verify

Checked 2026-09-17

Straightness/flatness (mm)	H	K	L
≤10	0,02	0,05	0,1
>10 – 30	0,05	0,1	0,2
>30 – 100	0,1	0,2	0,4
>100 – 300	0,2	0,4	0,8
>300 – 1000	0,3	0,6	1,2
>1000 – 3000	0,4	0,8	1,6

Perpendicularity (mm)	H	K	L
≤100	0,2	0,4	0,6
>100 – 300	0,3	0,6	1
>300 – 1000	0,4	0,8	1,5
>1000 – 3000	0,5	1	2

Symmetry (mm)	H	K	L
≤100	0,5	0,6	0,6
>100 – 300	0,5	0,6	1
>300 – 1000	0,5	0,8	1,5
>1000 – 3000	0,5	1	2

ISO 2768-2, Tables 4-7. Circular run-out has one value per class, independent of length.

Table values transcribed from commonly used, publicly published summaries of ISO 2768-1/-2. Verify against the original standard for contractually binding drawings.

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Questions

What does ISO 2768-mK mean?+

m is the medium linear class (2768-1), K the medium geometrical class (2768-2, withdrawn in 2021 — see the next question). For READING an existing drawing with mK in the title block: use the tables below. For a NEW drawing: check the current status of 2768-1 first and consider ISO 22081 for the geometrical class rather than copying mK by default.

When do I put the deviation next to the dimension?+

Below 0.5 mm the standard has no row. The deviation then sits next to the nominal size. Same if a table cell is empty (—).

Is this a fit?+

No. Fits (H7/g6, clearance, interference) are ISO 286. ISO 2768 is the default when there is no box around the dimension.

2768-2 is withdrawn. Why H/K/L?+

Part 2 was withdrawn in 2021; successor ISO 22081. The H/K/L tables here are useful for interpreting an EXISTING drawing that specifies mK — that is not the same as the successor standard automatically carrying over the same H/K/L scheme. Specify a NEW drawing per ISO 22081 (and check the current status of part 1 yourself), not by copying the old scheme. It does not replace a boxed, individually tolerated dimension.

General tolerances

Linear and angular dimensions (ISO 2768-1)

Geometric tolerances (ISO 2768-2:1989 — withdrawn)

Questions

Linear and angular dimensions (ISO 2768-1)

Geometric tolerances (ISO 2768-2:1989 — withdrawn)