M24 Washer Dimensions & Size

M24 washer dimensions are standardized for extreme-load structural and mechanical applications, including bridge construction, heavy industrial foundations, wind turbine towers, and large-scale maritime engineering. Specifically designed for fasteners with a 24 mm nominal diameter, these components ensure stable load distribution and protect mating surfaces from damage during high-torque tightening. This chart covers Form A plain washers, which feature a flat surface without a chamfer (unlike Form B).

The M24 size is a critical heavy-industry standard available in three series: the Normal Series (DIN 125A / ISO 7089) for standard load distribution, the Large Series (DIN 9021 / ISO 7093) for a massive increase in surface area, and the Small Series (DIN 433 / ISO 7092) for tight radial clearances. Based on these standards, M24 washers typically feature a hardness of 200 HV or 300 HV (Vickers Hardness), providing the structural integrity required to prevent “cupping” or deformation under the massive clamping forces of grade 8.8, 10.9, or 12.9 bolts.

Note: While these values reflect standard manufacturer datasheets, actual dimensions and tolerances may vary based on material (e.g., Stainless Steel vs. Hot-Dip Galvanized Steel) and manufacturing class. Always verify with the official product datasheet for critical applications.

Washer dimension diagram showing inner diameter, outside diameter, and thickness
M24 Standard Series Washer – DIN 125A/ISO 7089
Dimension Size (mm)
Min Max
Inner Diameter 25 25.33
Outside Diameter 43.38 44
Thickness 3.7 4.3
M24 Large Series Washer – DIN 9021/ISO 7093
Dimension Size (mm)
Min Max
Inner Diameter 26 26.84
Outside Diameter 70.1 72
Thickness 4 6
M24 Small Series Washer – DIN 433/ISO 7092
Dimension Size (mm)
Min Max
Inner Diameter 25 25.33
Outside Diameter 39.38 39
Thickness 3.7 4.3
  • Inner Diameter – The diameter of the hole, designed to clear the bolt/screw thread.
  • Outside Diameter – The total width of the washer, determining the load distribution area.
  • Thickness – The height of the washer, providing the spacing and structural support.
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Frequently Asked Questions

What does the “M24” designation mean on a washer?

The “M” stands for Metric, and the number represents the nominal thread diameter of the screw or bolt. An M24 washer is designed specifically for fasteners with a 24 mm nominal major diameter.

What is the difference between Form A and Form B washers?

The difference lies in the outer edge finish. Form A washers have a square, flat edge and are the most common. Form B washers include a 30° to 40° chamfer (beveled edge) on one side, according to DIN 125B and ISO 7090 standards.

When should I use a Large Series (DIN 9021) M24 washer?

The Large Series (DIN 9021 / ISO 7093) features a massive outside diameter of 72 mm. It is used when fastening into softer materials like structural timber or when bridging oversized holes in heavy base plates where the clamping force must be spread over a maximum area.

What does the HV rating mean on a washer?

HV stands for Vickers Hardness. For M24 fasteners, a rating of 200 HV or 300 HV is standard for steel and stainless steel. This ensures the washer resists the intense indentation forces generated during the high-torque installation of structural bolts.

What is the difference between Small Series (DIN 433) and Normal Series?

The Small Series (DIN 433 / ISO 7092) has a narrower outside diameter (39 mm) compared to the Normal Series (44 mm). It is intended for use with Socket Head Cap Screws or in recessed counterbores where space is restricted.

In which materials are M24 washers commonly available?

M24 washers are most frequently produced in Hot-Dip Galvanized Steel for outdoor structural applications due to superior corrosion resistance. They are also available in A4 (316) Stainless Steel for marine environments and Zinc-Plated Steel for indoor industrial use.