Metric washer dimensions: plain, large, heavy and spring washers
Plain washers in the normal, large and heavy series, and the split spring washer. The chart compares their inside and outside diameters and their thickness at each bolt size; each washer has its own page with the full table and a CAD file for every size.
Types of metric washers by standard
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ISO 7089 / DIN 125 plain washerPlain washer, normal series, product grade A, from M3 to M24. -
ISO 7093 / DIN 9021 large washerPlain washer with an outside diameter of about three times the bolt size, from M3 to M24. -
DIN 127 B spring lock washerSplit spring washer with square-cut ends (form B), from M3 to M24. -
DIN 7349 heavy washerThick plain washer, from M3 to M24.
Metric washer size chart: inside diameter, outside diameter and thickness
The size of a washer is the bolt it goes on. The inside diameter (d1) is the minimum, the outside diameter (d2) the maximum and the thickness (h) the nominal value of each standard. All plain washers of one size share the same hole.
| Bolt | Hole d1plain washers, mm | Normal d2ISO 7089, mm | Normal hISO 7089, mm | Large d2ISO 7093, mm | Large hISO 7093, mm | Heavy d2DIN 7349, mm | Heavy hDIN 7349, mm | Spring washer d2DIN 127 B, mm |
|---|---|---|---|---|---|---|---|---|
| M3 | 3.2 | 7 | 0.5 | 9 | 0.8 | 9 | 1 | 6.2 |
| M4 | 4.3 | 9 | 0.8 | 12 | 1 | 12 | 1.6 | 7.6 |
| M5 | 5.3 | 10 | 1 | 15 | 1 | 15 | 2 | 9.2 |
| M6 | 6.4 | 12 | 1.6 | 18 | 1.6 | 17 | 3 | 11.8 |
| M8 | 8.4 | 16 | 1.6 | 24 | 2 | 21 | 4 | 14.8 |
| M10 | 10.5 | 20 | 2 | 30 | 2.5 | 25 | 4 | 18.1 |
| M12 | 13 | 24 | 2.5 | 37 | 3 | 30 | 6 | 21.1 |
| M14 | 15 | 28 | 2.5 | 44 | 3 | 36 | 6 | 24.1 |
| M16 | 17 | 30 | 3 | 50 | 3 | 40 | 6 | 27.4 |
| M18 | 19 | 34 | 3 | 56 | 4 | 44 | 8 | 29.4 |
| M20 | 21 | 37 | 3 | 60 | 4 | 44 | 8 | 33.6 |
| M22 | 23 | 39 | 3 | 66 | 5 | 50 | 8 | 35.9 |
| M24 | 25 | 44 | 4 | 72 | 5 | 50 | 10 | 40 |
In the older DIN 9021, the large washer has a larger hole at M18, M20 and M24 and a thinner body at M5. Its page has the files for both versions.
Flat washer types: normal, large or heavy
The normal series (ISO 7089, formerly DIN 125) is the washer to use under a hex head or a nut on steel: its outside diameter covers the bearing face of the head. At M8 it is 16 mm across and 1.6 mm thick.
The large series (ISO 7093, formerly DIN 9021) has an outside diameter of about three times the bolt size, 24 mm at M8. It spreads the load on soft materials such as wood, plastic or thin sheet, and covers oversized or slotted holes.
The heavy washer (DIN 7349) is thicker, 4 mm at M8. It is written for bolts used with heavy-duty spring pins and is used wherever a thin washer could bend under the load.
The DIN 127 B spring washer is a split ring with its ends set apart, so it is not flat in use. Its outside diameter is smaller than that of a plain washer of the same size.
Metric washer sizes: common questions
- What does M10 mean on a washer?
- It is the bolt the washer fits: an M10 washer goes on an M10 bolt. Its hole is a little larger than the bolt, at least 10.5 mm for plain washers in ISO 7089, ISO 7093 and DIN 7349.
- What are the dimensions of an M18 washer?
- A normal ISO 7089 washer for M18 has a hole of at least 19 mm, an outside diameter of up to 34 mm and a thickness of 3 mm. The large ISO 7093 version is up to 56 mm across and 4 mm thick.
- Is DIN 125 the same as ISO 7089?
- For the sizes on this site, yes: DIN 125 form A and ISO 7089 give the same hole, outside diameter and thickness. Both are the normal series of plain washers without a chamfer.