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Reference Chart

ISO 2768 Tolerance Chart

ISO 2768 sets general tolerances for machined parts. It covers linear sizes, angles, and part shape. Use this chart when a drawing does not list a specific tolerance. Pick a class, find your size range, and read the allowed variation.

Showing 8 of 8 ranges

Quick Answer: What Is ISO 2768?

ISO 2768 is the international standard for general tolerances. It applies to linear sizes, angles and geometric features that have no individual tolerance called out on the drawing. ISO 2768-1 covers linear and angular dimensions in four classes (f fine, m medium, c coarse and v very coarse), and ISO 2768-2 covers geometric tolerances in three classes (H, K and L).

A callout like ISO 2768-mK means medium linear plus K-class geometric.

This chart lists ISO 2768 tolerance values in millimeters for: linear dimensions by nominal size range, angular dimensions by shorter-side length and geometric tolerances for straightness, flatness, perpendicularity and symmetry. Inputs are the nominal dimension and the tolerance class. The lookup tool returns the exact ± value from ISO 2768-1.

Common values (class m, medium): 0.5–3 mm → ±0.1 mm | 6–30 mm → ±0.2 mm | 30–120 mm → ±0.3 mm | 120–400 mm → ±0.5 mm | angular up to 10 mm → ±1° | geometric flatness 30–100 mm, K class → 0.2 mm.

ISO 2768-1 Linear Tolerances

These are the allowed deviations for linear dimensions like length, width, height, and diameter. All values are in millimeters. A dash means that class does not apply for that range.

Nominal 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 ±1.0
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 ±2.0 ±4.0
1000 – 2000 ±0.5 ±1.2 ±3.0 ±6.0
2000 – 4000 — ±2.0 ±4.0 ±8.0
No ranges match your search. Try a different term or filter.

ISO 2768-1 Angular Tolerances

These are the allowed deviations for angular dimensions. The shorter side of the angle sets which range to use. Values are shown in degrees and minutes of arc.

Nominal Length (mm) ▲ f — Fine ▲ m — Medium ▲ c — Coarse ▲ v — Very Coarse ▲
Up to 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'
Over 400 ±0°5' ±0°5' ±0°10' ±0°20'

ISO 2768-2 Geometric Tolerances

These tolerances control the shape and position of features. They apply when a drawing calls out ISO 2768-2. The uppercase letter (H, K, or L) sets the class. All values are in millimeters.

Straightness & Flatness

Nominal Range (mm) H K L
Up to 100.020.050.1
10 – 300.050.10.2
30 – 1000.10.20.4
100 – 3000.20.40.8
300 – 10000.30.61.2
1000 – 30000.51.02.0

Perpendicularity

Nominal Range (mm) H K L
Up to 1000.20.40.6
100 – 3000.30.61.0
300 – 10000.40.81.5
1000 – 30000.51.02.0

Symmetry

Nominal Range (mm) H K L
Up to 1000.50.60.6
100 – 3000.50.61.0
300 – 10000.50.81.5
1000 – 30000.51.02.0

Tolerance Lookup Tool

Enter a dimension and pick a class. The tool shows the exact tolerance from ISO 2768-1.

Tolerance

Visual Tolerance Band (ISO 2768)

Nominal: - Min: - Max: - Band: -
Tolerance band represents the allowed deviation around nominal.

When to Use Each Tolerance Class

  • Class f (Fine) — Use for tight fits and precision parts. Good for bearing bores, mating surfaces, and high-accuracy assemblies. Needs careful CNC work.
  • Class m (Medium) — The most common class. Works well for general CNC machined parts. Most shops can hold these tolerances without extra effort.
  • Class c (Coarse) — Use for parts where fit is not critical. Good for covers, brackets, and non-mating features. Keeps cost low.
  • Class v (Very Coarse) — Use for rough parts, castings, or flame-cut pieces. Not common for CNC work. Only applies to larger sizes.
  • A drawing note like "ISO 2768-mK" means linear class m and geometric class K. This is the most common callout for machined parts.
  • A dash (—) in the table means that class does not apply for that size range.
  • These are general tolerances. They only apply to features that do not have a specific tolerance called out on the drawing.

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Frequently Asked Questions

What is ISO 2768 and when should I use it?

ISO 2768 is a standard for general tolerances. It applies to linear and angular dimensions on machined parts. Use it when a drawing does not show a specific tolerance for a feature. It saves time by removing the need to add tolerances to every single dimension.

What is the difference between ISO 2768-1 and ISO 2768-2?

ISO 2768-1 covers linear and angular dimensions. It sets the allowed variation for lengths, widths, heights, and angles. ISO 2768-2 covers geometric tolerances like straightness, flatness, perpendicularity, and symmetry. A drawing often calls out both, such as ISO 2768-mK.

What does ISO 2768-mK mean on a drawing?

The lowercase letter is the linear tolerance class from ISO 2768-1. The uppercase letter is the geometric tolerance class from ISO 2768-2. So ISO 2768-mK means medium linear tolerances and K-class geometric tolerances. This is the most common callout for general machined parts.

Which ISO 2768 tolerance class should I pick for CNC machined parts?

For most CNC machined parts, class m (medium) works well. It matches what a good CNC machine can hold without extra effort. Use class f (fine) for tighter features. Use class c (coarse) for parts where fit is not critical, like covers or brackets.

Fits & Tolerances Reference Series

Related references — jump to the one you need:

Press Fit CalculatorShrink Fit CalculatorFit CalculatorHole/Shaft ToleranceH7/g6 Fit ChartISO 2768 TolerancesBearing Fit ChartTolerance Stack-UpTolerance CostTolerance Guide

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