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JIS B 0405 and B 0419 General Tolerance Calculator
The title block note governs most of the dimensions on a drawing, and it is not one number. Enter the dimension and the class and get the value that actually applies.
- Linear tolerance
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- Size band
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- Flatness / straightness
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- Perpendicularity
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- Symmetry
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- Circular run-out
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Reviewed 2026-09-23 against JIS B 0405, JIS B 0419, ISO 2768-1, ISO 2768-2.
Why this matters more than it looks
A shop that assumes the medium class on a drawing marked -fquotes a part that is legal against its own quote and wrong against yours. Between 6 and 30 mm that is plus or minus 0.2 mm against plus or minus 0.1 mm, applied to every dimension that carries no individual tolerance, which on most drawings is the majority.
The geometrical class is the one even careful shops skip, because the letter is appended to the same note. Class H circular run-out is 0.1 mm regardless of size, and on a shaft turned in two operations that is not automatic.
JIS B 0405 linear, permissible deviations in mm
| Nominal size | f | m | c | v |
|---|---|---|---|---|
| 0.5 to 3 | ±0.05 | ±0.1 | ±0.2 | - |
| over 3 to 6 | ±0.05 | ±0.1 | ±0.3 | ±0.5 |
| over 6 to 30 | ±0.1 | ±0.2 | ±0.5 | ±1 |
| over 30 to 120 | ±0.15 | ±0.3 | ±0.8 | ±1.5 |
| over 120 to 400 | ±0.2 | ±0.5 | ±1.2 | ±2.5 |
| over 400 to 1000 | ±0.3 | ±0.8 | ±2 | ±4 |
| over 1000 to 2000 | ±0.5 | ±1.2 | ±3 | ±6 |
| over 2000 to 4000 | - | ±2 | ±4 | ±8 |
Dimensions below 0.5 mm must be toleranced individually. The standard does not cover them.
Chamfers and external radii
| Nominal size | f and m | c and v |
|---|---|---|
| 0.5 to 3 | ±0.2 | ±0.4 |
| over 3 to 6 | ±0.5 | ±1 |
| over 6 | ±1 | ±2 |
Angular, by the shorter side of the angle
| Shorter side, mm | f and m | c | v |
|---|---|---|---|
| up to 10 | ±1 deg | ±1 deg 30' | ±3 deg |
| over 10 to 50 | ±0 deg 30' | ±1 deg | ±2 deg |
| over 50 to 120 | ±0 deg 20' | ±0 deg 30' | ±1 deg |
| over 120 to 400 | ±0 deg 10' | ±0 deg 15' | ±0 deg 30' |
| over 400 | ±0 deg 5' | ±0 deg 10' | ±0 deg 20' |
JIS B 0419 straightness and flatness
| Nominal length | H | K | L |
|---|---|---|---|
| up to 10 | 0.02 | 0.05 | 0.1 |
| over 10 to 30 | 0.05 | 0.1 | 0.2 |
| over 30 to 100 | 0.1 | 0.2 | 0.4 |
| over 100 to 300 | 0.2 | 0.4 | 0.8 |
| over 300 to 1000 | 0.3 | 0.6 | 1.2 |
| over 1000 to 3000 | 0.4 | 0.8 | 1.6 |
JIS B 0419 perpendicularity
| Shorter side | H | K | L |
|---|---|---|---|
| up to 100 | 0.2 | 0.4 | 0.6 |
| over 100 to 300 | 0.3 | 0.6 | 1 |
| over 300 to 1000 | 0.4 | 0.8 | 1.5 |
| over 1000 to 3000 | 0.5 | 1 | 2 |
JIS B 0419 symmetry and run-out
| Nominal length | H | K | L |
|---|---|---|---|
| up to 100 | 0.5 | 0.6 | 0.6 |
| over 100 to 300 | 0.5 | 0.6 | 1 |
| over 300 to 1000 | 0.5 | 0.8 | 1.5 |
| over 1000 to 3000 | 0.5 | 1 | 2 |
| Circular run-out, any size | 0.1 | 0.2 | 0.5 |
Three more rules complete B 0419. Roundness takes the numerical value of the diameter tolerance but never more than the circular run-out value for the class. Parallelism takes the larger of the dimensional tolerance or the flatness value. Cylindricity and coaxiality are not covered and must be drawn if they matter.
Disagrees with the standard in front of you? Write to sales at suscnc.com with the clause and we will correct it and say so. Full explanation inthe general tolerance guide.