Washer Sizes (Metric)
Metric Flat Washers
All sizes are in millimeters
Form A | Form B | Form C | |||||
Nominal Size | Internal Diameter | Outer | Thickness | Outer | Thickness | Outer | Thickness |
M1 | 1.1 | 2.5 | 0.3 | ||||
M1.2 | 1.3 | 3 | 0.3 | ||||
M1.4 | 1.5 | 3 | 0.3 | ||||
M1.6 | 1.7 | 4 | 0.3 | ||||
M2 | 2.2 | 5 | 0.3 | ||||
M2.5 | 2.7 | 6.5 | 0.5 | ||||
M3 | 3.2 | 7 | 0.5 | ||||
M3.5 | 3.7 | 7 | 0.5 | ||||
M4 | 4.3 | 9 | 0.8 | 10 | 0.8 | ||
M5 | 5.3 | 10 | 1 | 10 | 0.8 | 12.5 | 1 |
M6 | 6.4 | 12.5 | 1.6 | 12.5 | 0.8 | 14 | 1.6 |
M7 | 7.4 | 14 | 1.6 | 14 | 0.8 | ||
M8 | 8.4 | 17 | 1.6 | 17 | 1 | 21 | 1.6 |
M10 | 10.5 | 21 | 2 | 21 | 1.2 | 24 | 2 |
M12 | 13 | 24 | 2.5 | 24 | 1.6 | 28 | 2.5 |
M14 | 15 | 28 | 2.5 | 28 | 1.6 | 30 | 2.5 |
M16 | 17 | 30 | 3 | 30 | 2 | 34 | 3 |
M18 | 19 | 34 | 3 | 34 | 2 | 37 | 3 |
M20 | 21 | 37 | 3 | 37 | 2 | 39 | 3 |
23 | 39 | 3 | 39 | 2 | 44 | 3 | |
M24 | 25 | 44 | 4 | 44 | 2.5 | 50 | 4 |
M27 | 28 | 55 | 4 | 50 | 2.5 | 56 | 4 |
M30 | 31 | 56 | 4 | 56 | 2.5 | 60 | 4 |
Metric Spring Washers
All sizes are in millimeters
Rectangular | Square | ||||
Nominal Size | Internal Diameter | Outer | Thickness | Outer | Thickness |
M2 | 2.1 | 4.4 | 0.5 | ||
M2.5 | 2.6 | 5.1 | 0.6 | ||
M3 | 3.1 | 6.2 | 0.8 | 5.5 | 1 |
M3.5 | 3.6 | 6.7 | 0.8 | 6 | 1 |
M4 | 4.1 | 7.6 | 0.9 | 6.95 | 1.2 |
M5 | 5.1 | 9.2 | 1.2 | 8.55 | 1.5 |
M6 | 6.1 | 11.8 | 1.6 | 9.6 | 1.5 |
M8 | 8.1 | 14.8 | 2 | 12.75 | 2 |
M10 | 10.2 | 18.1 | 2.2 | 15.9 | 2.5 |
M12 | 12.2 | 21.1 | 2.5 | 17.9 | 2.5 |
M14 | 14.2 | 24.1 | 3 | 21.1 | 3 |
M16 | 16.2 | 27.4 | 3.5 | 24.3 | 3.5 |
M18 | 18.2 | 29.4 | 3.5 | 26.4 | 3.5 |
M20 | 20.2 | 33.6 | 4 | 30.5 | 4.5 |
M22 | 22.5 | 35.9 | 4 | 32.7 | 4.5 |
M24 | 24.5 | 40 | 5 | 35.7 | 5 |
M27 | 27.5 | 43 | 5 | 38.9 | 5 |
M30 | 30.5 | 48.2 | 6 | 43.9 | 6 |