Standard Tolerances (Excerpts from JIS B 0405-1991/JIS B 0419-1991)
2026/05/07
[Scope of Application]
JIS B 0405 is intended to simplify drawing specifications and prescribes standard tolerances—specifically four tolerance grades—for length and angle dimensions for which no individual tolerance specifications are provided.
JIS B 0419 specifies general geometric tolerances in three tolerance classes for regulating features that do not have individual geometric tolerance specifications, with the aim of simplifying drawing instructions.
This standard applies primarily to parts manufactured by subtractive processes.
Tolerance on the length dimension, excluding the chamfered portion
Unit [mm]
| Tolerance Class | Classification of reference dimensions | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Symbol | Description | 0.5 or more and 3 or less | Greater than 3 and 6 or less | Greater than 6 and 30 or less | Greater than 30 and less than or equal to 120 | Greater than 120 and less than or equal to 400 | Greater than 400 and less than or equal to 1000 | Over 1,000 and 2,000 or less | Over 2000 and 4000 or less |
| Tolerance | |||||||||
| f | Precision Grade | ±0.05 | ±0.05 | ±0.1 | ±0.15 | ±0.2 | ±0.3 | ±0.5 | - |
| m | Intermediate | ±0.1 | ±0.1 | ±0.2 | ±0.3 | ±0.5 | ±0.8 | ±1.2 | ±2 |
| c | Coarse | ±0.2 | ±0.3 | ±0.5 | ±0.8 | ±1.2 | ±2 | ±3 | ±4 |
| v | Extra coarse | - | ±0.5 | ±1 | ±1.5 | ±2.5 | ±4 | ±6 | ±8 |
*For reference dimensions less than 0.5 mm, the tolerance must be specified individually following the reference dimension.
Tolerances for the dimensions of chamfered sections (corner rounding and corner chamfer dimensions)
Unit [mm]
| Tolerance Class | Classification of reference dimensions | |||
|---|---|---|---|---|
| Symbol | Description | 0.5 or more and 3 or less | Greater than 3 and less than or equal to 6 | Greater than 6 |
| Tolerance | ||||
| f | Precision grade | ±0.2 | ±0.5 | ±1 |
| m | Intermediate | |||
| c | Coarse | ±0.4 | ±1 | ±2 |
| v | Extra-coarse grade | |||
*For reference dimensions less than 0.5 mm, the tolerance must be specified individually following the reference dimension.
Tolerances for angular dimensions
Unit [mm]
| Tolerance Class | Classification based on the length of the shorter side of the angle (in mm) | |||||
|---|---|---|---|---|---|---|
| Symbol | Description | 10 or less | Greater than 10 and 50 or less | Greater than 50 and 120 or less | More than 120 and 400 or less | Over 400 |
| Tolerance | ||||||
| f | Precision Grade | |||||
| m | Intermediate | ±1° | ±30′ | ±20′ | ±10′ | ±5′ |
| c | Coarse | ±1°30′ | ±1° | ±30′ | ±15′ | ±10′ |
| v | Extra coarse | ±3° | ±2° | ±1° | ±30′ | ±20′ |
Standard tolerances for straightness and flatness
Unit [mm]
| Tolerance class | Nominal length class | |||||
|---|---|---|---|---|---|---|
| 10 or less | Over 10 and up to 30 | Over 30 and up to 100 | Over 100 and up to 300 | Over 300 and 1,000 or less | Over 1000 and up to 3000 | |
| Straightness tolerance and flatness tolerance | ||||||
| H | 0.02 | 0.05 | 0.1 | 0.2 | 0.3 | 0.4 |
| K | 0.05 | 0.1 | 0.2 | 0.4 | 0.6 | 0.8 |
| L | 0.1 | 0.2 | 0.4 | 0.8 | 1.2 | 1.6 |
*When selecting tolerances from this table, straightness is based on the length of the corresponding line, flatness is based on the length of the longer side for rectangles, and for circular shapes, it is based on the diameter.
Standard tolerance for perpendicularity
Unit [mm]
| Tolerance Class | Classification of nominal length of the shorter side | |||
|---|---|---|---|---|
| 100 or less | Over 100 and up to 300 | Over 300 and up to 1000 | Over 1000 and up to 3000 | |
| Perpendicularity tolerance | ||||
| H | 0.2 | 0.3 | 0.4 | 0.5 |
| K | 0.4 | 0.6 | 0.8 | 1 |
| L | 0.6 | 1 | 1.5 | 2 |
Standard tolerance for symmetry
Unit [mm]
| Tolerance class | Nominal length class | |||
|---|---|---|---|---|
| 100 or less | Over 100 and up to 300 | Over 300 and up to 1000 | Over 1000 and up to 3000 | |
| Symmetry Tolerance | ||||
| H | 0.5 | |||
| K | 0.6 | 0.8 | 1 | |
| L | 0.6 | 1 | 1.5 | 2 |
Standard tolerance for circumferential runout
Unit [mm]
| Tolerance Class | Circumferential runout tolerance |
|---|---|
| H | 0.1 |
| K | 0.2 |
| L | 0.5 |
Other Technical Documents
↓You can download the following technical documents as a single PDF file.
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- Hexagon Socket Head Cap Screw Standards List | Excerpt from JIS B 1176
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- Shapes and Dimensions of Hex Bolts (Component Grade A) (Excerpt from JIS B 1180-1985)
- How to Use Hex Socket Set Screws
- Mechanical Properties of Steel Bolts and Screws (Excerpt from JIS B 1051-2000)
- Shapes and Dimensions of Hexagonal Wrenches (Hex Wrenches/L-Wrenches/Hex Wrenches) (Excerpt from JIS B 4648:2008)
- List of Standards for Dimensions and Tolerances of Parallel Keys and Keyways (Excerpt from JIS B 1301-1996/JIS B 1301-1959 [Old JIS])
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- Glossary of Screw Terms (JIS B 0101:2013)
- Glossary of Fit Tolerances (Excerpt from JIS B 0401-1:2016)
- Glossary of Terms for Chains, Sprockets, and Accessories (Excerpt from JIS B 1812:2015)
- Glossary of Friction Belt Transmission Terms (Excerpt from JIS B 1860:2018)
- Technical Drawing—Terminology (Excerpt from JIS Z 8114:1999)