Washer Standards & Dimension Reference
The standards we build to — with dimension tables across DIN, ASME / USS / SAE, ISO and GB. Use it to specify the right washer, then send the standard, size and material in your RFQ.
We manufacture to your national standard.
304 / 316 / 316L washers produced to all major national and international standards. Tell us which one you specify — we build to its dimensions, tolerance class and surface condition, metric or imperial.
Cross-standard equivalents on request (e.g. DIN 125 ≈ ISO 7089 ≈ GB/T 97 ≈ JIS B 1256). Don’t see your standard? Send the spec or a sample and we will match it.
Which standard maps to which washer.
A quick map from standard to washer type, with the note that matters when you specify. All available in 304, 316 or 316L stainless, metric or imperial.
| Standard | Washer type | Note |
|---|---|---|
| DIN 125 | Flat washer — regular OD | General-purpose plain washer. ≈ ISO 7089 / 7090. |
| DIN 433 | Flat washer — small OD | Reduced outside diameter for tight spacing. |
| DIN 9021 | Flat washer — large OD / fender | OD ≈ 3× nominal to spread load. ≈ ISO 7093. |
| DIN 127 | Spring washer — split ring | Helical split lock washer against vibration. |
| DIN 7980 | Spring washer — heavy | Heavier section split lock for higher load. |
| DIN 6798 | Tooth lock washer | Internal or external serrated, anti-rotation. |
| DIN 988 | Shim / support washer | Precision thickness shims for spacing / take-up. |
| ASME B18.21.1 | Plain washer — US Type A | Inch-series plain washers; covers SAE and USS. |
| USS | Flat washer — wide | Larger OD inch pattern within ASME B18.21.1. |
| SAE | Flat washer — narrow | Smaller OD inch pattern within ASME B18.21.1. |
| ISO 7089 / 7090 / 7093 | Flat washers — metric | 7089 plain · 7090 chamfered · 7093 large OD. |
| GB/T 95 | Flat washer (Chinese GB) | Metric plain washer to Chinese national standard. |
| GB/T 93 | Spring washer (Chinese GB) | Split-ring spring lock to Chinese national standard. |
DIN 125 A flat washer dimensions.
Regular-OD general-purpose plain washer — the most-specified flat washer in metric assembly. DIN 125 ≈ ISO 7089 / 7090; the full range runs M1.6 to M64.
| Thread d | Inside dia d1 | Outside dia d2 | Thickness s |
|---|---|---|---|
| M3 | 3.2 | 7 | 0.5 |
| M4 | 4.3 | 9 | 0.8 |
| M5 | 5.3 | 10 | 1.0 |
| M6 | 6.4 | 12 | 1.6 |
| M8 | 8.4 | 16 | 1.6 |
| M10 | 10.5 | 20 | 2.0 |
| M12 | 13 | 24 | 2.5 |
| M14 | 15 | 28 | 2.5 |
| M16 | 17 | 30 | 3.0 |
| M18 | 19 | 34 | 3.0 |
| M20 | 21 | 37 | 3.0 |
| M22 | 23 | 39 | 3.0 |
| M24 | 25 | 44 | 4.0 |
| M27 | 28 | 50 | 4.0 |
| M30 | 31 | 56 | 4.0 |
| M33 | 34 | 60 | 5.0 |
| M36 | 37 | 66 | 5.0 |
DIN 9021 large-OD / fender washer dimensions.
Oversized outside diameter — roughly three times nominal thread — to distribute clamp load over soft, slotted or oversized holes. ISO 7093 equivalent.
| Thread d | Inside dia d1 | Outside dia d2 | Thickness s |
|---|---|---|---|
| M4 | 4.3 | 12 | 1.0 |
| M5 | 5.3 | 15 | 1.2 |
| M6 | 6.4 | 18 | 1.6 |
| M8 | 8.4 | 24 | 2.0 |
| M10 | 10.5 | 30 | 2.5 |
| M12 | 13 | 37 | 3.0 |
| M14 | 15 | 44 | 3.0 |
| M16 | 17 | 50 | 3.0 |
| M20 | 22 | 60 | 4.0 |
USS & SAE plain washers, inch series.
ASME B18.21.1 Type A plain washers in the two common inch patterns: SAE (narrow OD) for finished bolted joints and USS (wide OD) for general construction. Dimensions in inches.
| Bolt | SAE — narrow | USS — wide | ||||
|---|---|---|---|---|---|---|
| ID | OD | Thk | ID | OD | Thk | |
| 1/4 | .281 | .625 | .065 | .312 | .734 | .065 |
| 5/16 | .344 | .688 | .065 | .375 | .875 | .083 |
| 3/8 | .406 | .812 | .065 | .438 | 1.000 | .083 |
| 1/2 | .531 | 1.062 | .095 | .562 | 1.375 | .109 |
| 5/8 | .656 | 1.312 | .095 | .688 | 1.750 | .134 |
| 3/4 | .812 | 1.469 | .134 | .812 | 2.000 | .148 |
Metric ↔ imperial & cross-standard equivalence.
Standards rarely line up to the same number, so treat cross-references as the nearest equivalent, not an identical part. The relationships that hold in practice:
- DIN 125 ≈ ISO 7089 / 7090 — regular-OD flat washer; ISO 7090 is the chamfered variant.
- DIN 9021 ≈ ISO 7093 — large-OD / fender washer, OD roughly 3× nominal thread.
- GB/T 95 ≈ DIN 125 / ISO 7089 and GB/T 93 ≈ DIN 127 for the Chinese national standards.
- ASME B18.21.1 defines the inch-series plain washers; SAE is the narrow pattern and USS the wide pattern.
Metric and imperial do not interchange dimensionally — an M6 DIN 125 is not a 1/4" SAE washer. When a drawing mixes systems, send the controlling standard and the dimensions that matter and we match the part to it.
Give us four things and a quote follows quickly: the standard (e.g. DIN 125 or USS), the size (M8 or 3/8"), the material (304 / 316 / 316L) and the finish. A drawing with toleranced dimensions overrides any standard reference — send it and we build to the print.
Got the dimension — now pick the grade.
The standard fixes the geometry; the stainless grade decides how long the washer survives its environment. 304 covers most indoor and structural work; 316 / 316L earns its premium in marine, chemical and coastal service.
Standards questions, answered.
Is DIN 125 the same as ISO 7089?
They are closely equivalent. DIN 125 A and ISO 7089 are both plain flat washers, product grade A, with very similar inside diameter, outside diameter and thickness across the common metric range — so for most assemblies they are interchangeable. ISO 7089 is the current international reference and DIN 125 the long-established German standard. Tell us which one your drawing calls out and we build to it.
What is the difference between DIN 125 and DIN 9021?
Both are flat washers, but DIN 9021 (large-OD / fender washer, ISO 7093 equivalent) has a much larger outside diameter — roughly three times the nominal thread size — to spread load over soft, slotted or oversized holes. DIN 125 is the regular-OD general-purpose flat washer. Use DIN 9021 for sheet metal, soft materials and slotted connections; use DIN 125 for standard bolted joints.
Can you supply washers to our own drawing or non-standard sizes?
Yes. Beyond the DIN, ASME, ISO and GB standards listed here, we stamp non-standard washers to your drawing or sample — special outside diameter, inside diameter, thickness, chamfers, hole shapes and material or finish. Send a print or a sample with the tolerances that matter and we quote against it, with first-article inspection on request.
Tell us what you need.
Send specs or a drawing and we will come back with pricing, lead time and material options. No account, no minimum to ask.
- ✓ 304 / 316 / 316L, DIN & ASME or custom
- ✓ Replies from engineers, typically within one business day
- ✓ Samples and material certificates available