GB vs DIN vs ISO Fastener Standards: The Complete Comparison Chart
Chinese manufacturers produce fasteners under the GB/T (Guobiao / national standard) system, while European buyers usually specify DIN numbers and global projects often reference ISO standards. For the vast majority of metric fasteners the three systems describe the same part — same thread (metric M profile), same head dimensions, same strength classes. This chart gives you the practical cross-reference so you can order with confidence.
1. How the three systems relate
- DIN (Deutsches Institut für Normung) is the oldest system and is still the de-facto trade language in the fastener market.
- ISO standards largely adopted DIN dimensions from the 1980s onward, so “ISO 4762” and “DIN 912” describe the same screw with tiny differences in head diameter tolerance.
- GB/T standards were historically derived from DIN, then progressively harmonized with ISO. A GB/T 70.1 socket cap screw is dimensionally interchangeable with DIN 912 / ISO 4762.
Bottom line: you can mix the three systems when ordering from SFX — send us whichever number you have, and we confirm the exact part before quoting.
2. Screws & bolts
| GB/T | DIN | ISO | Product |
|---|---|---|---|
| GB/T 70.1 | DIN 912 | ISO 4762 | Hexagon socket head cap screws |
| GB/T 5782 | DIN 931 | ISO 4014 | Hex bolts, partially threaded |
| GB/T 5783 | DIN 933 | ISO 4017 | Hex bolts, fully threaded |
| GB/T 77 | DIN 913 | ISO 4026 | Socket set screws, flat point |
| GB/T 78 | DIN 914 | ISO 4027 | Socket set screws, cone point |
| GB/T 79 | DIN 915 | ISO 4028 | Socket set screws, dog point |
| GB/T 80 | DIN 916 | ISO 4029 | Socket set screws, cup point |
| GB/T 818 | DIN 7985 | ISO 7045 | Cross recessed pan head screws |
| GB/T 819.1 | DIN 965 | ISO 7046-1 | Cross recessed countersunk screws |
| GB/T 845 | DIN 7981 | ISO 7049 | Pan head self-tapping screws |
| GB/T 846 | DIN 7982 | ISO 7050 | Countersunk self-tapping screws |
| GB/T 65 | DIN 84 | ISO 1207 | Slotted cheese head screws |
| GB/T 67 | DIN 85 | ISO 1580 | Slotted pan head screws |
Shop by DIN number: DIN 912 · DIN 7991 flat head · DIN 7984 low head · DIN 913 · DIN 914 · DIN 915 · DIN 916 · DIN 931 · DIN 933
Worked example: the DIN 912 socket head cap screw guide takes the GB/T 70.1 / DIN 912 / ISO 4762 row above and shows what the head diameter, socket size and thread-length numbers actually are, size by size.
3. Nuts
| GB/T | DIN | ISO | Product |
|---|---|---|---|
| GB/T 6170 | DIN 934 | ISO 4032 | Hex nuts, style 1 |
| GB/T 6172.1 | DIN 439 B | ISO 4035 | Hex thin nuts (jam nuts) |
| GB/T 889.1 | DIN 985 | ISO 10511 | Nylon insert lock nuts |
| GB/T 802 | DIN 1587 | — | Hex domed cap nuts (one piece) |
| GB/T 6177 | DIN 6923 | ISO 4162 | Hex flange nuts |
Shop: DIN 934 · DIN 985 · DIN 1587 cap nuts · DIN 6923 flange nuts
4. Rivet nuts — a special case
Rivet nuts (blind threaded inserts) are standardized in China under the GB/T 17880 series (e.g. GB/T 17880.1 for flat head types). Unlike the parts above, rivet nuts never had a classic DIN number — internationally they are usually ordered by drawing or dimensional spec. Every SFX rivet nut listing shows the full dimension table, so you can match against your drawing directly: browse rivet nuts.
5. Washers & pins
| GB/T | DIN | ISO | Product |
|---|---|---|---|
| GB/T 97.1 | DIN 125 A | ISO 7089 | Plain washers, normal series |
| GB/T 97.2 | DIN 125 B | ISO 7090 | Plain washers, chamfered |
| GB/T 848 | DIN 433 | ISO 7092 | Plain washers, small series |
| GB/T 96 | DIN 9021 | ISO 7093 | Plain washers, large series |
| GB/T 93 | DIN 127 B | — | Spring lock washers |
| GB/T 119.1 | DIN 7 | ISO 2338 | Parallel dowel pins, unhardened |
| GB/T 119.2 | DIN 6325 | ISO 8734 | Parallel dowel pins, hardened |
| GB/T 879.1 | DIN 1481 | ISO 8752 | Spring pins, slotted, heavy type |
| GB/T 91 | DIN 94 | ISO 1234 | Split cotter pins |
| GB/T 880 | DIN 1444 | ISO 2341 | Clevis pins |
| GB/T 894 | DIN 471 | — | Retaining rings for shafts |
| GB/T 893 | DIN 472 | — | Retaining rings for bores |
| GB/T 896 | DIN 6799 | — | E-clip retaining rings |
| GB/T 1096 | DIN 6885 | ISO 773 | Parallel keys |
6. Strength classes & materials match 1:1
Property classes and stainless grades are internationally identical, so no conversion is needed:
| Carbon steel class | Stainless grade | Meaning |
|---|---|---|
| 4.8 / 5.8 | A2-50 | Low strength — general hardware |
| 8.8 | A2-70 | Medium-high — the most common class |
| 10.9 | A4-80 | High strength — structural / marine |
| 12.9 | — | Alloy steel, highest standard class (socket screws) |
7. FAQ
Is GB/T 70.1 exactly the same as DIN 912?
For practical purposes yes — same M-thread, same head, same key size. Differences are limited to tolerance details (e.g. head diameter tolerance bands) and do not affect interchangeability in assembly.
Can I mix GB parts with DIN/ISO parts in one assembly?
Yes for standard metric fasteners. Thread profiles are all metric M per ISO 68-1, so a GB/T 70.1 screw fits a DIN 912 hole and vice versa. For safety-critical or certified assemblies, always confirm the required standard with your engineer.
Which standard should I specify when ordering from China?
Either. Send us your DIN, ISO or GB/T number — SFX produces against all three and confirms the exact part before quoting. If you only have a drawing, upload it and we match it for you.
Are GB standard parts cheaper?
For the same dimensions and property class, GB-produced parts are typically more cost-effective simply because they come from Chinese production lines at source — that is the SFX model: factory pricing, zero minimum order quantity, worldwide tracked shipping.
What does the “T” in GB/T mean?
“推荐” (recommended). GB/T are voluntary national standards; mandatory ones are plain GB. In the fastener trade, GB/T is the relevant series and is the one used throughout this chart.
Ready to order?
All products on SFX Fasteners list both DIN numbers and Chinese standard references. Browse the DIN 912 socket screws or the full rivet nut range — every item ships worldwide with calculated freight and a proforma invoice for your bank transfer.