Free Engineering Tool
General Tolerances ISO 2768-2 Calculator
Look up geometrical (form and position) tolerances per ISO 2768-2. Select tolerance class, feature type, and nominal range.
Results
Straightness / Flatness Tolerances
Applicable to straight-line features and flat surfaces. The nominal range refers to the longer side of the surface or the length of the feature.
| Range (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 Tolerances
Applicable to features nominally perpendicular to a datum surface. The nominal range refers to the shorter side of the angle.
| Range (mm) | H | K | L |
|---|---|---|---|
| ≤ 100 | 0.2 | 0.4 | 0.6 |
| 100 – 300 | 0.3 | 0.6 | 1.0 |
| 300 – 1000 | 0.4 | 0.8 | 1.5 |
| 1000 – 3000 | 0.5 | 1.0 | 2.0 |
Symmetry Tolerances
| Range (mm) | H | K | L |
|---|---|---|---|
| ≤ 100 | 0.5 | 0.6 | 0.6 |
| 100 – 300 | 0.5 | 0.6 | 1.0 |
| 300 – 1000 | 0.5 | 0.8 | 1.5 |
| 1000 – 3000 | 0.5 | 1.0 | 2.0 |
Circular Runout Tolerances
| Class | Tolerance (mm) |
|---|---|
| H | 0.1 |
| K | 0.2 |
| L | 0.5 |
⚠️ Note: ISO 2768-2 general tolerances apply only when no specific geometrical tolerance is indicated on the drawing. Features with explicit GD&T callouts override these values.
ISO 2768-2 specifies general tolerances for geometrical (form and position) features when no individual tolerance is indicated on a drawing. It covers straightness, flatness, perpendicularity, symmetry, and circular runout.
There are three classes:
- H — Most precise
- K — Medium (most common)
- L — Coarsest
The class is indicated in the title block, e.g., ISO 2768-mK.
It is referenced in the title block as “ISO 2768-mK” where the lowercase letter (m) is the ISO 2768-1 dimensional tolerance class and the uppercase letter (K) is the ISO 2768-2 geometrical tolerance class.
No. It applies only to features without individual geometrical tolerances. Features with explicit GD&T symbols are controlled by those specific tolerances instead.
ISO 2768-1 covers general dimensional (linear and angular) tolerances. ISO 2768-2 covers general geometrical (form and position) tolerances. They are complementary and usually referenced together.
The procedures described on this page were developed and field-tested by the Vibromera team using the Balanset-1A, a portable dual-channel balancer and vibration analyzer for on-site rotor balancing.
Professional field balancing instruments and software. Used in 50+ countries.
Nikolai Shelkovenko
Nikolai Shelkovenko is a vibration analysis engineer and the founder and CEO of Vibromera. For more than 15 years he has balanced rotating equipment in the field rather than on a test bench: mulchers, industrial fans, crushers, centrifuges, shafts and spindles. That work is what the Balanset instruments grew out of — they were designed as a tool a specialist can carry to the machine and use alone, on site, not as laboratory equipment. Vibromera was founded in 2017 and has been based in Porto, Portugal, since 2023. Development, assembly and support of the Balanset line all happen here. The flagship instrument is the Balanset-1A, a portable analyser for single- and two-plane balancing and for vibration diagnostics. Nikolai is personally involved in customer support, in working through difficult balancing cases and in the development of the software. He works with customers worldwide, in any language.
