DIN Changeover to ISO

Table 1 – ISO-DIN previous standards
Table 2 – Technical Term of delivery and basic standards
Table 3 – DIN-ISO Changes to widths Across Flates

What is a Standard?

Technical standards are basically agreed-upon rules created so everyone involved in design, engineering, production, and construction can work consistently. These rules define how things should be made, tested, and named so that products from different companies fit and work together.

Previously in Germany, standards were mainly managed by DIN (German Institute for Standardization). Over time, standardization expanded to the European level (EN standards) and globally through ISO (International Organization for Standardization).

Why Are Standards Changing?

DIN standards are gradually being replaced by European (EN) and international (ISO) standards. The goal is to unify the way products are defined around the world and remove trade barriers.

When a product standard becomes an EN or ISO standard, the DIN version is usually withdrawn.

Product Names and Codes

When standards change, sometimes the product names or designations also change. This can confuse people because it may seem like the product itself has changed — but in most cases, the product remains the same; only the name or code is updated to match the new system

A DIN standard and its ISO equivalent generally specify the same type of product, the same dimensions, and the same technical requirements. The numbers just look different (for example, DIN 931 ˜ ISO 4014).

Will the Change Affect Product Quality?

For most fasteners, the switch from DIN to ISO does not change the product’s dimensions or performance.

For example:

• DIN bolts with dimensions M10, M12, and M14 are identical to ISO versions.

• Some larger sizes (like M18 and M22) may have slight dimensional changes, but nothing that affects practical use.

In general, screw dimensions remain almost identical, so compatibility is not an issue.

Why Make the Change at All?

Standardizing under ISO makes global trade easier.

Instead of every country using its own system, ISO provides a worldwide standard, so manufacturers, suppliers, and customers all speak the same “technical language.”

Even though the change may seem unnecessary at first, it reduces confusion and means products can be matched internationally

without problems.

DIN-ISO successor standards ISO-DIN previous standards ISO

DIN	ISO	DIN	ISO	DIN	ISO	ISO	DIN	ISO	DIN	ISO	DIN
1	2339	931	4014	6914	7412	1051	660/661	4036	439	8673	934
7	2338	933	4017	6915	7414	1207	84	4161	6923	8673	971
84	1207	934	4032	6916	7416	1234	94	4762	912	8674	971-2
85	1580	934	8673	6921	8102	1479	7976	4766	551	8676	961
94	1234	960	8765	6923	4161	1481	7971	7040	982	8677	603
125	7089	961	8676	6924	7040	1482	7972	7040	6924	8733	7979
125	7090	963	2009	6925	7042	1483	7973	7042	980	8734	6325
126	7091	964	2010	7343	8750	1580	85	7042	6925	8735	7979
417	7435	965	7046	7343	8751	2009	963	7045	7985	8736	7978
427	2342	966	7047	7344	8748	2010	964	7046	965	8737	7977
433	7092	971-1	8673	7346	13337	2338	7	7047	966	8738	1440
438	7436	971-2	8674	7971	1481	2339	1	7049	7981	8740	1473
439	4035	980	7042	7972	1482	2341	1434	7050	7982	8741	1474
439	4036	980	10513	7973	1483	2342	427	7051	7983	8742	1475
440	7094	982	7040	7976	1479	2936	911	7072	11024	8744	1471
551	4766	982	10512	7977	8737	4014	931	7089	125	8745	1472
553	7434	985	10511	7978	8736	4016	601	7090	125	8746	1476
555	4034	1440	8738	7979	8733	4017	933	7091	126	8747	1477
558	4018	1444	2341	7979	8735	4018	558	7092	433	8748	7344
601	4016	1471	8744	7981	7049	4026	913	7093	9021	13337	7346
603	8677	1472	8745	7982	7050	4027	914	7094	440	8750	7343
660	1051	1473	8740	7983	7051	4028	915	7412	6914	8751	7343
661	1051	1474	8741	7985	7045	4029	916	7414	6915	8752	1481
911	2936	1475	8742	7991	10642	4032	934	7416	6916	8765	960
912	4762	1476	8746	9021	7093	4034	555	7434	553	10642	7991
913	4026	1477	8747	11024	7072	4035	439	7435	417	10511	985
914	4027	1481	8752					7436	438	10512	982
915	4028	6325	8734					8102	6921	10513	980
916	4029

Technical terms of delivery and basic standards:

DIN (old)	ISO	DIN (new) / DIN EN	Description	Notes
267 Part 20	–	DIN EN ISO 6157-2	Surface condition checks for nuts	No major updates
267 Part 21	–	DIN EN ISO 10484	Nut widening test procedure	No substantial changes
DIN ISO 225	225	DIN EN 20225	Symbols & terminology for fasteners (ISO 225:1991)	Unchanged
DIN ISO 273	273	DIN EN 20273	Standard hole sizes for bolts & screws (ISO 273: 1991)	No new items
DIN ISO 898 Part 1	898-1	DIN EN ISO 898-1	Mechanical strength of steel fasteners (ISO 898-1: 1988)	No relevant modifications
267 Part 4	898-2	DIN EN 20898-2	Fasteners with defined proof load (ISO-2: 1992)	No major revisions
DIN ISO 898 Part 6	898-6	DIN EN ISO 898 Part 6	Strength properties for nuts with load rating (ISO-6: 1988)	No noteworthy updates
267 Part 19	6157-1	DIN EN 26157 Part 1	Surface irregularities for bolts & studs (ISO 6157-1: 1988)	Stable
267 Part 19	6157-3	DIN EN 26157 Part 3	Surface criteria for special-requirement fasteners (ISO 6157-3: 1988)	No major notes
DIN ISO 7721	7721	DIN EN 27721	Head-shape guidelines for countersunk screws (ISO 7721:1983)	No updates
267 Part 9	–	DIN ISO 4042	Electroplated coatings on fasteners	No significant revision
267 Part 1	–	DIN ISO 8992	General specifications for threaded fasteners	No change
267 Part 5	–	DIN EN ISO 3269	Inspection & acceptance rules	Unchanged
267 Part 11	–	DIN EN ISO 3506 (1-3)	Corrosion-resistant steel fasteners — performance & delivery	No notable modifications
267 Part 12	–	DIN EN ISO 2702	Heat-treated tapping screws — performance	No new information
267 Part 18	8839	DIN EN 28839	Mechanical properties for non-ferrous fasteners (ISO 8839: 1986)	No major revisions

DIN-ISO changes to widths Across Flats:

Hex Size (Across Flats)	DIN Value	ISO Value
M10	17 mm	16 mm
M12	19 mm	18 mm
M14	22 mm	21 mm
M22	32 mm	34 mm

Small Metric Screw:

DIN (old)	ISO	DIN (new) / DIN EN	Description	Changes
84	1207	DIN EN 21207	Slotted cheese-head screws, grade A (ISO 1207: 1992)	Altered head size & diameter
85	1580	DIN EN 21580	Slotted flat-head screws, grade A	Head height & diameter adjusted
963	2009	DIN EN 22009	Countersunk screws with slotted drive, type A	Minor head dimension changes
964	2010	DIN EN 22010	Oval countersunk screws with slot, type A	Some dimensions revised
965	7046-1	DIN EN 27046-1	Cross-recess countersunk screws (standard head), class A, strength 4.8	Updated head & diameter specs
965	7046-2	DIN EN 27046-2	Cross-recess countersunk screws (modified head), grade A, strength 4.8	Head profile & diameter tweaked
966	7047	DIN EN 27047	Oval countersunk screws with cross recess, grade A	Head height & width revised
7985	7045	DIN EN 27045	Pan-head screws with cross recess, grade A	Diameter & head sizing updated

Pins and Screws:

DIN (previous)	ISO Ref.	Updated DIN/EN	Description	Notes
1	2339	DIN EN 22339	Taper pins, untreated; ISO-based specification (ISO 2339: 1986)	Length includes rounded tips
7	2338	DIN EN 22338	Parallel pins of mild steel or stainless steel (ISO 2338: 1986)	Length includes rounded tips
1440	8738	DIN EN 28738	Washers for clevis pins — Grade A type (ISO 8738: 1986)	Outer diameter changed in some versions
1443	2340	DIN EN 22340	Clevis pins, no head (ISO 2340: 1986)	No major updates
1444	2341	DIN EN 22341	Clevis pins with head (ISO 2341: 1986)	No major updates
1470	8739	DIN EN 8739	Grooved pins, parallel grooved, with pilot (ISO 8739: 1997)	No revisions of note
1471	8744	DIN EN 8744	Grooved pins — full-length taper (ISO 8744: 1997)	No revisions of note
1472	8745	DIN EN 8745	Grooved pins — half-length tapered (ISO 8745: 1997)	No revisions of note
1473	8740	DIN EN 8740	Grooved pins — full-length, chamfered (ISO 8740: 1997)	No revisions of note
1474	8741	DIN EN 8741	Grooved pins — reverse-taper type (ISO 8741: 1997)	No revisions of note
1475	8742	DIN EN 8742	Grooved pins — one-third length center groove (ISO 8742: 1997)	Higher shear resistance
1476	8746	DIN EN 8746	Grooved pins — domed head (ISO 8746: 1997)	No revisions of note
1477	8747	DIN EN 8747	Grooved pins — countersunk head (ISO 8747: 1997)	No revisions of note
1481	8752	DIN EN 8752	Straight slotted spring pins — heavy-duty (ISO 8752: 1997)	Bevel angle removed
6325	8734	DIN EN 8734	Hardened parallel dowel pins (ISO 8734: 1997)	Shape A/B removed
7977	8737	DIN EN 28737	Threaded taper pins, external thread type; non-hardened (based on ISO 8737:1986)	No revisions of note
7978	8736	DIN EN 28736	Threaded taper pins, internal thread type; non-hardened (according to ISO 8736:1986)	No revisions of note
7979	8733	DIN EN 8733	Parallel pins with an internal thread, produced from mild steel or austenitic stainless steel (referencing ISO 8733:1997)	No revisions of note
7979	8735	DIN EN 8735	Parallel pins with internal threading, manufactured from hardened steel or martensitic stainless steel (per ISO 8735:1997)	No revisions of note

Tapping Screws:

DIN (Old)	ISO	DIN / DIN-EN	Description	Updates
7971	1481	DIN ISO 1481	Slotted pan-head tapping screw (ISO 1481: 1983)	Minor head size adjustments
7972	1482	DIN ISO 1482	Flat countersunk slotted tapping screw	Updated height tolerance
7973	1483	DIN ISO 1483	Oval raised countersunk tapping screw	Revised head profile
7976	1479	DIN ISO 1479	Hexagon tapping screw	Minor head height change
7981	7049	DIN ISO 7049	Cross recessed pan tapping screw	Drive geometry updated
7982	7050	DIN ISO 7050	Cross recessed flat countersunk screw	Head/diameter changes
7983	7051	DIN ISO 7051	Oval cross recessed countersunk tapping screw	Diameter refinement

Hexagon Head Screws and Nuts:

DIN (Old)	ISO	DIN / DIN-EN	Description	Updates
439 T1	4036	DIN EN 24036	Thin hex nut (unchamfered)	Across-flats values revised
439 T2	4035	DIN EN 24035	Thin nut — alternate style	4 AF dimensions modified
555	4034	DIN EN 24034	Hex nut – grade C	Nut height changes
558	4018	DIN EN 24018	Hex head screw – grade C	AF changes
601	4016	DIN EN 24016	Hex bolt – grade C	Aligned with DIN 555 updates
931	4014	DIN EN 24014	Hex bolt with shank	Across-flats updated
933	4017	DIN EN 24017	Hex screw – full thread	Minor AF changes
934 Type 1	8673	DIN EN 28673	Hex nut – style 1	Height and AF refined
960	8765	DIN EN 28765	Hex bolt – part threaded	Shank & AF updates
961	8676	DIN EN 28676	Hex screw – grade 10.9	AF dimensions adjusted

DIN Changeover to ISO

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