ISO 4014 is the international dimensional standard for hexagon head bolts, a partial thread widely known as ISO 4014 bolts. It is the ISO-harmonized metric equivalent of the legacy DIN 931 standard, and is increasingly the preferred reference on international and export project specifications. This page is part of our full fastener standards index. Jade Alloys manufactures and supplies hex bolts to ISO 4014 and equivalent standards in carbon steel, alloy steel, and stainless steel.
Current Norm & Equivalent Norms
- Current norm: DIN EN ISO 4014
- Equivalent norms: DIN 931; CSN 021101; PN 82101; UNI 5737; EU 24014
ISO 4014 vs ISO 4017 - What's the Difference?
ISO 4014 bolts have a partial thread with a smooth, unthreaded shank section below the head, improving shear resistance in clamped joints, the ISO equivalent of DIN 931. ISO 4017 is fully threaded, the ISO equivalent of DIN 933. ISO 4014 is generally preferred for longer bolts in shear-critical structural or machinery applications.
ISO 4014 Bolt Dimensions
Dimensions in millimeters. Important: while DIN 931 and ISO 4014 share most dimensions, width across flats (s) and width across corners (e) differ at a handful of sizes M10, M12, M14, and M22 where ISO 4014 uses a slightly smaller across-flats dimension than the legacy DIN 931 value. Both values are shown below where they differ.
| Size | Pitch (P) | Head Height (K) | Radius (R) min | Width Across Flats (s) | Width Across Corners (e) min |
|---|---|---|---|---|---|
| M3 | 0.5 | 2.0 | 0.1 | 5.5 | 6.01 |
| M4 | 0.7 | 2.8 | 0.2 | 7.0 | 7.66 |
| M5 | 0.8 | 3.5 | 0.2 | 8.0 | 8.79 |
| M6 | 1.0 | 4.0 | 0.25 | 10.0 | 11.05 |
| M8 | 1.25 | 5.3 | 0.4 | 13.0 | 14.38 |
| M10 | 1.5 | 6.4 | 0.4 | 17.0 (DIN 931) / 16.0 (ISO 4014) | 18.90 (DIN 931) / 17.77 (ISO 4014) |
| M12 | 1.75 | 7.5 | 0.6 | 19.0 (DIN 931) / 18.0 (ISO 4014) | 21.10 (DIN 931) / 20.03 (ISO 4014) |
| M14 | 2.0 | 8.8 | 0.6 | 22.0 (DIN 931) / 21.0 (ISO 4014) | 24.49 (DIN 931) / 23.36 (ISO 4014) |
| M16 | 2.0 | 10.0 | 0.6 | 24.0 | 26.75 |
| M18 | 2.5 | 11.5 | 0.6 | 27.0 | 30.14 |
| M20 | 2.5 | 12.5 | 0.8 | 30.0 | 33.53 |
| M22 | 2.5 | 14.0 | 0.8 | 32.0 (DIN 931) / 34.0 (ISO 4014) | 38.85 (DIN 931) / 37.72 (ISO 4014) |
| M24 | 3.0 | 15.0 | 0.8 | 36.0 | 39.98 |
| M27 | 3.0 | 17.0 | 1.0 | 41.0 | 45.20 |
| M30 | 3.5 | 18.7 | 1.0 | 46.0 | 50.85 |
| M36 | 4.0 | 22.5 | 1.0 | 55.0 | 60.79 |
| M42 | 4.5 | 26.0 | 1.2 | 65.0 | 71.30 |
| M48 | 5.0 | 30.0 | 1.6 | 75.0 | 82.60 |
| M56 | 5.5 | 35.0 | 2.0 | 85.0 | 93.56 |
| M64 | 6.0 | 40.0 | 2.0 | 95.0 | 104.90 |
Thread Length (b)
| Size | b (L ≤ 125mm) | b (125mm < L ≤ 200mm) | b (L > 200mm) |
|---|---|---|---|
| M6 | 18 | 24 | – |
| M8 | 22 | 28 | – |
| M10 | 26 | 32 | 45 |
| M12 | 30 | 36 | 49 |
| M16 | 38 | 44 | 57 |
| M20 | 46 | 52 | 65 |
| M24 | 54 | 60 | 73 |
| M30 | 66 | 72 | 85 |
| M36 | – | 84 | 97 |
| M42 | – | 96 | 109 |
| M48 | – | 108 | 121 |
Thread length varies by bolt length bracket, in millimeters:H2 – Legend
- s – width across flats (size of the hexagon)
- e – width across corners
- k – height of the head
- d – nominal diameter of the thread
- b – thread length
- l – length of bolt
- r – fillet radius under the head
Weight Chart for ISO 4014 Hex Bolts
| Length (mm) | M4 | M5 | M6 | M7 | M8 | M10 | M12 | M14 | M16 | M18 | M20 | M22 | M24 | M30 | M36 | M48 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 25 | 3.12 | 4.86 | ||||||||||||||
| 30 | 3.61 | 5.64 | 8.06 | 12.7 | ||||||||||||
| 35 | 4.04 | 6.42 | 9.13 | 13.6 | 18.2 | |||||||||||
| 40 | 4.53 | 7.20 | 10.2 | 15.1 | 20.3 | 35.0 | ||||||||||
| 45 | 7.98 | 11.3 | 16.6 | 22.2 | 38.0 | 53.6 | ||||||||||
| 50 | 8.76 | 12.3 | 18.1 | 24.2 | 41.1 | 58.1 | 82.0 | |||||||||
| 55 | 13.4 | 19.5 | 25.8 | 43.8 | 62.6 | 88.1 | 115 | |||||||||
| 60 | 14.4 | 21.0 | 27.8 | 46.9 | 67.0 | 94.1 | 123 | |||||||||
| 65 | 22.5 | 29.8 | 50.0 | 70.3 | 98.8 | 131 | 171 | 219 | ||||||||
| 70 | 24.0 | 31.8 | 53.1 | 74.7 | 105.0 | 139 | 181 | 231 | 281 | |||||||
| 75 | 33.7 | 56.2 | 79.1 | 111.0 | 147 | 191 | 243 | 296 | ||||||||
| 80 | 35.7 | 59.3 | 83.6 | 117.0 | 155 | 200 | 255 | 311 | 392 | |||||||
| 85 | 62.4 | 88.1 | 123.0 | 163 | 210 | 267 | 326 | 410 | ||||||||
| 90 | 65.5 | 92.4 | 127.0 | 171 | 220 | 279 | 341 | 428 | 712 | |||||||
| 95 | 68.6 | 96.8 | 133.0 | 179 | 230 | 291 | 356 | 446 | 739 | |||||||
| 100 | 71.7 | 101.0 | 139.0 | 186 | 240 | 303 | 370 | 464 | 767 | |||||||
| 110 | 109.0 | 151.0 | 202 | 260 | 327 | 400 | 500 | 823 | 1240 | |||||||
| 120 | 118.0 | 164.0 | 218 | 280 | 351 | 430 | 535 | 880 | 1320 | |||||||
| 130 | 174.0 | 230 | 296 | 374 | 450 | 560 | 920 | 1390 | ||||||||
| 140 | 185.0 | 246 | 316 | 398 | 480 | 595 | 975 | 1470 | 2860 | |||||||
| 150 | 262 | 336 | 422 | 510 | 630 | 1030 | 1550 | 3010 | ||||||||
| 160 | 278 | 356 | 446 | 540 | 665 | 1085 | 1630 | 3160 | ||||||||
| 170 | 376 | 470 | 570 | 700 | 1140 | 1710 | 3300 | |||||||||
| 180 | 396 | 494 | 600 | 735 | 1200 | 1790 | 3440 | |||||||||
| 190 | 519 | 630 | 770 | 1250 | 1870 | 3580 | ||||||||||
| 200 | 544 | 660 | 805 | 1310 | 1950 | 3720 | ||||||||||
| 220 | 720 | 870 | 1420 | 2110 | 4010 | |||||||||||
| 240 | 935 | 1530 | 2270 | 4290 | ||||||||||||
| 260 | 1640 | 2430 | 4570 | |||||||||||||
| 280 | 1750 | 2590 | 4850 | |||||||||||||
| 300 | 1860 | 2750 | 5130 | |||||||||||||
| 320 | 5410 | |||||||||||||||
| 340 | 5690 |
Weights are approximate reference values only; actual weight depends on exact length, thread length, material, and coating. For a precise calculation at any size, length, and material, use our Metal Weight Calculator.
ISO 4014 Equivalent Standards
| Standard | Relationship |
|---|---|
| DIN 931 | Legacy German equivalent; dimensions match except at M10, M12, M14, M22 (see table above) |
| ISO 4017 | Fully-threaded counterpart within the ISO system |
| ASME B18.2.1 | Inch-series hex bolt equivalent (different dimensional system) |
| IS 1364 | Indian Standard equivalent for hexagon head bolts |
| CSN 021101 | Czech Standard equivalent |
| PN 82101 | Polish Standard equivalent |
| UNI 5737 | Italian Standard equivalent |
| EU 24014 | Legacy EU-prefix numbering equivalent (predates full ISO harmonization) |
Material, Property Classes & Markings
ISO 4014 bolts are marked to identify material and property class:
- Steel: property classes 5.6, 5.8, 8.8, 10.9, 12.9
- Stainless steel: A2, A4
- Non-ferrous: brass
- Standard thread tolerance class: 6g
- Alloy steel to material specifications such as ASTM A193 for high-temperature applications
Applications of ISO 4014 Bolts
ISO 4014 hex bolts are used across general engineering, machinery assembly, structural connections, and piping support wherever a partial-thread hex bolt is specified, particularly on export and internationally-specified projects favoring ISO over legacy national standards.
Frequently Asked Questions
1. Is ISO 4014 exactly the same as DIN 931?
2. What nut and washer pair with ISO 4014 bolts?
3. When should I choose ISO 4014 over ISO 4017?
4. What is the current norm for ISO 4014?
Need ISO 4014 bolts in a specific size, material, or property class? Contact our technical team or view the full Fastener Standards hub.
