Standard Comparison

DIN 125-A vs ISO 7089 — what actually differs

Quick answer: DIN 125 A and ISO 7089 call out the same dimensions for plain washers, normal series — all 29 sizes in our compiled tables match (d1, d2, h and weight). ISO 7089:2000 is the current standard; DIN 125 A is the legacy German designation. The chamfered counterpart is ISO 7090 / DIN 125 B — plain and chamfered washers are not interchangeable when the chamfer matters.

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1. Dimensions at a glance

Key sizes — DIN 125 A and ISO 7089 (identical values)
Washer size	For thread	d1 — inside dia. (mm)	d2 — outside dia. (mm)	h — thickness (mm)	Weight kg / 1,000 pcs
6.4	M6	6.4–6.62	11.57–12	1.4–1.8	1.02
8.4	M8	8.4–8.62	15.57–16	1.4–1.8	1.83
10.5	M10	10.5–10.77	19.48–20	1.8–2.2	3.57
13	M12	13–13.27	23.48–24	2.3–2.7	6.27
17	M16	17–17.27	29.48–30	2.7–3.3	11.3
21	M20	21–21.33	36.38–37	2.7–3.3	17.2

Full tables for all sizes: ISO 7089 M1.6–M36 and DIN 125 A on their standard pages.

2. What actually differs

Standard status. DIN 125 A is the legacy German designation; ISO 7089:2000 is the current international standard for plain washers, normal series, product grade A. Legacy drawings still reference DIN 125 A.
Edge form. DIN 125 A and ISO 7089 are plain (unchamfered) washers. DIN 125 B and ISO 7090 are the chamfered versions of the same normal series — do not substitute one for the other when the chamfer is functionally required.
Dimensions. All 29 sizes in our compilation match: d1 (inside diameter), d2 (outside diameter), h (thickness) and theoretical weight per 1,000 pieces.
Product grade. ISO 7089 specifies product grade A (a dimensional tolerance class). The drawing should state the grade required; a legacy DIN 125 A callout usually implies the standard normal-series tolerances.
Hardness class. Washers are ordered to a hardness class (commonly 140HV or 200HV) separately from the standard; confirm it on the drawing or order.
Materials and finishes. Carbon steel and stainless A2/A4 as standard; zinc plating, hot-dip galvanizing, zinc-nickel and dacromet finishes are quoted to the order.

3. Which standard should I specify?

New drawings: ISO 7089:2000 (plain, normal series). Legacy drawings: DIN 125 A parts are dimensionally interchangeable when the hardness class and finish match. If the application needs a chamfer, specify ISO 7090 / DIN 125 B instead — the plain washer is a different part.

4. Substitution checklist

Read the drawing: DIN 125 A, ISO 7089, or dimensions only?
Confirm plain vs chamfered: DIN 125 A / ISO 7089 are plain; DIN 125 B / ISO 7090 are chamfered.
Confirm the hardness class (140HV / 200HV) and the material (carbon steel / A2 / A4).
Confirm the coating class and any salt-spray requirement.
On new drawings use ISO 7089:2000; keep DIN 125 A as a note only if the customer requests it.

5. Frequently asked questions

Is DIN 125 A the same as ISO 7089?

Dimensionally yes. In our compiled data all 29 sizes match (d1, d2, h and weight). DIN 125 A is the legacy German designation; ISO 7089:2000 is the current international standard.

What is the difference between DIN 125 A and DIN 125 B?

DIN 125 A is the plain (unchamfered) washer; DIN 125 B is the chamfered version. ISO 7089 is the plain washer and ISO 7090 is the chamfered equivalent.

Can I substitute DIN 125 A for ISO 7089?

Yes when dimensions, hardness class and finish match. The substitution should be recorded on the inspection documents.

Which hardness class should I order?

Commonly 140HV or 200HV; the right class depends on the bolted joint and the drawing. State it explicitly on the order — the standard number alone does not define hardness.

Is ISO 7089 still valid?

Yes — ISO 7089:2000 is the current standard for plain washers, normal series, product grade A. DIN 125 A is the legacy designation still found on older drawings.

Data compiled by Longze QA from the published standard tables; last verified 2026-11-06. Informational only — the drawing and the purchase order govern the delivered part.