Hex Nuts manufactured to ISO 4032 follow a specific scope. This page summarizes that scope, lists every dimension the standard fixes, and points to the most common cross-references.
ISO 4032 — Scope
ISO 4032 specifies the dimensions and tolerances of hex nuts. Material, property class, surface finish and packaging are governed by separate documents in the same standards family (for example ISO 898-1 for the mechanical property classes of bolts and screws).
Tolerance & Product Grades
ISO 4032, alongside the related ISO 4032 / ISO 4033 entries on this site, specifies product grades (typically A or B for fine work and C for general engineering) and tolerance classes for the controlling dimensions. Choose the grade against the precision your application requires.
Dimensions Specified by ISO 4032
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e min (mm) | Nut height m style 1 (mm) | Nut height m style 2 (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M1 | 0.25 | 2.5 | 2.71 | 0.8 | - | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M1.2 | 0.25 | 3.0 | 3.28 | 1.0 | - | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M1.4 | 0.3 | 3.0 | 3.28 | 1.2 | - | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M1.6 | 0.35 | 3.2 | 3.48 | 1.3 | - | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M2 | 0.4 | 4.0 | 4.32 | 1.6 | - | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M2.5 | 0.45 | 5.0 | 5.45 | 2.0 | - | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M3 | 0.5 | 5.5 | 6.01 | 2.4 | - | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M3.5 | 0.6 | 6.0 | 6.58 | 2.8 | - | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M4 | 0.7 | 7.0 | 7.66 | 3.2 | - | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M5 | 0.8 | 8.0 | 8.79 | 4.0 | 5.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M6 | 1.0 | 10.0 | 11.05 | 5.0 | 6.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M8 | 1.25 | 13.0 | 14.38 | 6.5 | 8.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M10 | 1.5 | 16.0 | 17.77 | 8.0 | 10.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M12 | 1.75 | 18.0 | 20.03 | 10.0 | 12.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M14 | 2.0 | 21.0 | 23.36 | 11.0 | 14.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M16 | 2.0 | 24.0 | 26.75 | 13.0 | 16.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M18 | 2.5 | 27.0 | 29.56 | 15.0 | 18.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M20 | 2.5 | 30.0 | 32.95 | 16.0 | 20.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M22 | 2.5 | 32.0 | 35.03 | 18.0 | 22.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M24 | 3.0 | 36.0 | 39.55 | 19.0 | 24.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M27 | 3.0 | 41.0 | 45.2 | 22.0 | 27.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M30 | 3.5 | 46.0 | 50.85 | 24.0 | 30.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M33 | 3.5 | 50.0 | 55.37 | 26.0 | 33.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M36 | 4.0 | 55.0 | 60.79 | 29.0 | 36.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M39 | 4.0 | 60.0 | 66.44 | 31.0 | 39.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M42 | 4.5 | 65.0 | 71.3 | 34.0 | 42.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M45 | 4.5 | 70.0 | 76.95 | 36.0 | 45.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M48 | 5.0 | 75.0 | 82.6 | 38.0 | 48.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M52 | 5.0 | 80.0 | 88.25 | 42.0 | 52.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M56 | 5.5 | 85.0 | 93.56 | 45.0 | 56.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M60 | 5.5 | 90.0 | 99.21 | 48.0 | 60.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
| M64 | 6.0 | 95.0 | 104.86 | 51.0 | 64.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
Equivalent Standards
ISO 4032 hex nuts correspond to DIN 934 (style 1).
Companion Standards
ISO 4032 controls only the geometry of hex nuts. The mechanical strength is set by ISO 898-1 (bolts and screws) or ISO 898-2 (nuts); the surface finish is governed by separate finish standards (e.g. ISO 4042 for electroplating). For corrosion testing, the relevant document is ISO 9227 (neutral salt spray).