Metric clearance values on an engineering drawing should come from the design authority or current licensed standard. The calculator helps when no formal requirement exists and the user understands the limitation.
Documented clearance recommendations
These values reproduce the cited manufacturer recommendations, not protected standard tables. A blank cell means that fit category is not supplied by this dataset.
| Fastener | Close | General | Free |
|---|---|---|---|
| M3 | — | 3.4 mm · 3.4 mm | — |
| M4 | — | 4.5 mm · 4.5 mm | — |
| M5 | — | 5.5 mm · 5.5 mm | — |
| M6 | — | 6.6 mm · 6.6 mm | — |
| M8 | — | 9.0 mm · 9.0 mm | — |
| M10 | — | 11.0 mm · 11.0 mm | — |
| M12 | — | 13.5 mm · 13.5 mm | — |
| M14 | — | 15.5 mm · 15.5 mm | — |
| M16 | — | 17.5 mm · 17.5 mm | — |
| M18 | — | 20.0 mm · 20.0 mm | — |
| M20 | — | 22.0 mm · 22.0 mm | — |
| M22 | — | 24.0 mm · 24.0 mm | — |
| M24 | — | 26.0 mm · 26.0 mm | — |
Example: M6 fastener
The general workshop setting returns 6.5 mm for a nominal 6 mm fastener. That is a transparent arithmetic result, not a claim that 6.5 mm is the required ISO normal clearance for every M6 joint.
When to stop using the calculator
Use the specified drawing value when available. Escalate to engineering when joint slip, bearing area, fatigue, sealing, edge distance or positional tolerance matters.
The fit words are descriptive labels for this calculator only and must not be read as a formal tolerance class.
Technical references
- Cle-Line C01112 Tap and Drill Recommendations — Greenfield Industries / Cle-Line. Accessed 2026-11-09.
- ISO 261 ISO general purpose metric screw threads — General plan — International Organization for Standardization. Accessed 2026-11-09.
Standards references identify scope and terminology; protected dimensional tables are not reproduced.