ISO 2768 is an international standard that defines general tolerances for linear and angular dimensions on engineering drawings. Part 1 (ISO 2768-1) covers linear and angular tolerances in four classes: f (fine), m (medium), c (coarse), and v (very coarse). It eliminates the need to specify individual tolerances on every dimension.

When should I use general tolerances?

General tolerances apply to all dimensions on a drawing that do not have individual tolerances specified. They are suitable for features produced by standard machining operations where normal workshop accuracy is sufficient. For critical fits, mating surfaces, or precision features, specific tolerances should be applied.

What is the difference between f, m, c, and v tolerance classes?

The four classes represent increasing levels of permissible deviation: f (fine) has the tightest tolerances, m (medium) is the most commonly used for general machining, c (coarse) is for rough machining or non-critical parts, and v (very coarse) is for castings and flame-cut parts.

How are angular tolerances applied in ISO 2768-1?

Angular tolerances depend on the shorter side of the angle. For example, if the shorter side is ≤10 mm, the angular tolerance for class m is ±1°. As the shorter side increases, the angular tolerance decreases. This is defined in Table 2 of ISO 2768-1.

How do I note ISO 2768-1 on a drawing?

The standard is referenced in the drawing title block as 'ISO 2768-m' (for medium class) or 'ISO 2768-fH' when combined with Part 2 (geometrical tolerances). Simply write the standard designation followed by the tolerance class letter.

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General Tolerances Calculator — ISO 2768-1

Look up general tolerance values per ISO 2768-1 by tolerance class and nominal dimension. Linear and angular tolerances with full reference tables.

ISO 2768-1 Linear Tolerances Angular Tolerances

Results

Linear Tolerance

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Tolerance Class

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Dimension Range

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Upper Limit

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Lower Limit

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Angular Tolerance (shorter side)

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Table 1 — Linear Dimensions (Permissible Deviations in mm)

Range (mm)	f (Fine)	m (Medium)	c (Coarse)	v (Very Coarse)
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

Table 2 — Angular Dimensions (Permissible Deviations)

Shorter Side (mm)	f (Fine)	m (Medium)	c (Coarse)	v (Very Coarse)
≤ 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°5′	±0°5′	±0°10′	±0°20′

ℹ️ Note: ISO 2768-1 applies to all dimensions on the drawing that do not have individual tolerances specified. The tolerance class letter is placed in the title block, e.g. “ISO 2768-m”.

What Are General Tolerances?

General tolerances per ISO 2768-1 define permissible deviations for linear and angular dimensions that do not carry individual tolerance indications on a drawing. They represent normal workshop accuracy achievable with standard machining processes.

The actual dimension must fall within the range:

Tolerance Class Selection

f (Fine) — Precision machining, tight fits. Requires careful process control.
m (Medium) — Most commonly used. Standard machining (turning, milling, drilling).
c (Coarse) — Rough machining, welded structures, non-critical parts.
v (Very Coarse) — Castings, flame-cut parts, forgings.

Drawing Notation

Example — Title Block Notation

For linear tolerances only: ISO 2768-m

Combined with geometrical tolerances (ISO 2768-2): ISO 2768-mK

This means: linear tolerance class “m” + geometrical tolerance class “K”.

⚠️ Important: General tolerances do not apply to dimensions with individual tolerances, reference dimensions (in parentheses), or dimensions governed by other standards.

General Tolerances Calculator | ISO 2768-1 | Linear & Angular

Published by Nikolai Shelkovenko on February 15, 2026 February 15, 2026