DIN to ISO Fastener Equivalents: Metric Standards Guide
Metric fasteners are commonly specified to DIN (German) or ISO (International) standards. This guide maps frequent DIN numbers to their ISO counterparts and flags whether they’re fully interchangeable or if you should check the spec for subtle differences (head height/diameter, pitch options, tolerances). Use it as a quick reference when sourcing or substituting parts.
Fully Interchangeable DIN and ISO Fasteners
| Description | DIN | ISO | Interchangeability | Notes |
|---|---|---|---|---|
| Cross Recessed Pan Head Screw | DIN 7985 | ISO 7045 | Fully interchangeable | General-purpose pan head. |
| Socket Head Cap Screw, Coarse | DIN 912 | ISO 4762 | Fully interchangeable | Primary SHCS spec (coarse). |
| Socket Head Cap Screw, Fine | DIN 912 | ISO 12474 | Fully interchangeable | Fine thread variant. |
| Socket Set Screw – Flat Point | DIN 913 | ISO 4026 | Fully interchangeable | Headless (grub) screw, flat. |
| Socket Set Screw – Cone Point | DIN 914 | ISO 4027 | Fully interchangeable | Headless, cone. |
| Socket Set Screw – Dog Point | DIN 915 | ISO 4028 | Fully interchangeable | Headless, dog. |
| Socket Set Screw – Cup Point | DIN 916 | ISO 4029 | Fully interchangeable | Headless, cup. |
| Slotted Headless Screw with Shank | DIN 427 | ISO 2342 | Fully interchangeable | Slotted variant. |
| Hex Head Bolts (FT), Metric Coarse | DIN 933 | ISO 4017 | Fully interchangeable | Full thread hex bolts. |
| Hex Head Bolts (PT), Metric Coarse | DIN 931 | ISO 4014 | Fully interchangeable | Partial thread hex bolts. |
| Hex Head Bolts (PT), Metric Coarse | DIN 601 | ISO 4016 | Fully interchangeable | Alt coarse hex PT. |
| Hex Head Bolts (FT), Metric Coarse | DIN 558 | ISO 4018 | Fully interchangeable | Alt coarse hex FT. |
| Hex Head Bolts (PT), Metric Fine | DIN 960 | ISO 8765 | Fully interchangeable | Fine thread PT. |
| Hex Head Bolts (FT), Metric Fine | DIN 961 | ISO 8676 | Fully interchangeable | Fine thread FT. |
| Hex Nut – Thin | DIN 439 | ISO 4035, 4036 | Fully interchangeable | Chamfered/unchamfered covered by ISO pair. |
| Hex Nut – Thin (Chamfered), Fine | DIN 439 | ISO 8675 | Fully interchangeable | Fine thread thin nut. |
| Washer, Plain | DIN 125 | ISO 7089, 7090 | Fully interchangeable | Normal vs chamfered faces. |
| Washer, Plain Small | DIN 433 | ISO 7092 | Fully interchangeable | Small series. |
| Washer, Plain Large | DIN 9021 | ISO 7093 | Fully interchangeable | Large OD series. |
Partially Interchangeable (Check Spec)
| Description | DIN | ISO | Interchangeability | Typical Differences |
|---|---|---|---|---|
| Slotted Cheese Head Screw | DIN 84 | ISO 1207 | Check spec | Head dia/height tolerances may vary. |
| Slotted Flat Head (Countersunk) | DIN 963 | ISO 2009 | Check spec | Countersink/head geometry differences. |
| Slotted Raised Countersunk | DIN 964 | ISO 2010 | Check spec | Raised profile may differ slightly. |
| Cross Recessed Flat Head | DIN 965 | ISO 7046 | Check spec | Head/countersink geometry. |
| Cross Recessed Raised Countersunk | DIN 966 | ISO 7047 | Check spec | Raised profile/diameter tolerance. |
| Flat Head Socket Cap | DIN 7991 | ISO 10642 | Check spec | Head angle/height differences exist. |
| Hex Head Bolts with Flange | DIN 6921 | DIN EN 1665 | Check spec | Flange OD/serrations/tolerance windows. |
| Hex Head Self-Tapping Screws | DIN 7976 | ISO 1479 | Check spec | Point/thread form variations. |
| Cross Recessed Pan Head Tapping | DIN 7981 | ISO 7049 | Check spec | Head/point differences. |
| Cross Recessed Flat Head Tapping | DIN 7982 | ISO 7050 | Check spec | Countersink/head angle. |
| Cross Recessed Raised Countersunk Tapping | DIN 7983 | ISO 7051 | Check spec | Raised profile tolerance. |
| Hex Nut – Thin (Unchamfered) | DIN 439 | ISO 4036 | Check spec | Edge prep varies; check bearing face. |
| Prevailing Torque Flange Nut | DIN 6926 | DIN EN 1663, 1666 | Check spec | Deformation style/serrations differ. |
| Prevailing Torque Flange Nut | DIN 6927 | DIN EN 1664, 1667 | Check spec | Variant series. |
| Prevailing Torque All-Metal Nut | DIN 980, 6925 | ISO 7042, 10513 | Check spec | Prevail torque requirements vary. |
| Prevailing Torque Nylon Insert Nut | DIN 982, 6924 | ISO 7040, 10512 | Check spec | Insert height/torque windows. |
| Nylon Insert Lock Nut (thin) | DIN 985 | ISO 10511 | Check spec | Thin pattern; verify heights. |
| Slotted Set Screw – Flat | DIN 551 | ISO 4766 | Check spec | Slot width/tolerance differences. |
| Slotted Set Screw – Cone | DIN 553 | ISO 7434 | Check spec | Point geometry. |
| Hex Nut with Flange | DIN 6923 | DIN EN 1661 | Check spec | Flange geometry/tolerance. |
| Hex Weld Nut with Flange | DIN 977 | ISO 21670 | Check spec | Weld bosses/OD differ by series. |
| Slotted Set Screw – Long Dog | DIN 417 | DIN EN 27435 | Check spec | Legacy to EN conversion. |
| Slotted Set Screw – Cup | DIN 438 | DIN EN 27436 | Check spec | Legacy to EN conversion. |
- Head height/diameter and countersink angle (esp. flat/raised heads).
- Thread pitch availability (coarse vs fine) and tolerance class.
- Flange OD/serrations on flange nuts/bolts.
- Prevailing torque test method ranges (nylon insert vs all-metal).
DIN ↔ ISO Equivalents: Frequently Asked Questions
Are DIN and ISO fasteners the same thing?
No. Many have direct ISO counterparts and are interchangeable (e.g., DIN 912 ↔ ISO 4762), but others differ slightly in head geometry, pitch options, or tolerances. Check drawings for critical assemblies.
Which pairs are commonly treated as drop-in equivalents?
Popular examples include DIN 912 ↔ ISO 4762 (socket head cap), DIN 933 ↔ ISO 4017 (hex, full thread), DIN 931 ↔ ISO 4014 (hex, partial thread), and set screws DIN 913/914/915/916 ↔ ISO 4026/4027/4028/4029.
Do torque values change if I substitute DIN for ISO?
Torque is driven by property class, lubrication, and joint design more than the standard number. If material class and finish are the same (e.g., 8.8 vs 8.8), torque guidance is typically unchanged—always follow the drawing/torque spec.
What should I double-check before swapping standards?
Confirm head dimensions (height/diameter/countersink), thread pitch availability, flange OD/serrations on flange styles, and prevailing torque windows on lock nuts.
Can Monster Bolts help locate the ISO version of a DIN part?
Absolutely. We stock DIN/ISO metric fasteners and can help confirm interchangeability. We ship quickly from Milton, Florida. See Metric Fasteners or Contact Us.