1/2 Washer Dimensions & Size

1/2″ washers are commonly used with 1/2-inch bolts and nuts or screws in structural assemblies, heavy construction, industrial equipment, and automotive applications. They are designed to distribute load, protect surfaces, and improve fastening stability under higher clamping forces. Under the USS standard, a 1/2″ plain washer typically has a nominal inner diameter of 9/16″ and a nominal outer diameter of 1-3/8″, with a thickness range of 0.086–0.132 inch. Under the SAE standard, it has a nominal inner diameter of 17/32″ and a nominal outer diameter of 1-1/16″, with a typical thickness range of 0.097–0.177 inch. All dimensions shown are based on USS and SAE standards.

Disclaimer: Washer dimensions and tolerances may vary by standard, manufacturer, material, or finish. Always confirm critical dimensions using the official product datasheet before installation.

Washer Diagram Anatomy
USS Standard
Dimensions Nominal Size (in) Actual Size (in)
Min Max
Inner Diameter 9/16 0.557 0.577
Outer Diameter 1-3/8 1.368 1.405
Thickness Not specified 0.086 0.132
SAE Standard
Dimensions Nominal Size (in) Actual Size (in)
Min Max
Inner Diameter 17/32 0.526 0.546
Outer Diameter 1-1/16 1.055 1.092
Thickness Not specified 0.097 0.177
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Frequently Asked Questions

What is the difference between USS and SAE washer standards?

USS (United States Standard) washers generally have a larger outer diameter and thicker profile, making them suitable for structural and heavy-duty applications. SAE (Society of Automotive Engineers) washers are typically smaller in diameter and thinner, designed for tighter tolerances and more compact assemblies.

What size is a 1/2″ washer?

The size of a 1/2″ washer depends on the standard. Under the USS standard, it typically has a nominal inner diameter of 9/16″ and a nominal outer diameter of 1-3/8″. Under the SAE standard, it usually has a nominal inner diameter of 17/32″ and a nominal outer diameter of 1-1/16″.

What is the inner diameter of a 1/2″ washer?

The inner diameter is larger than the bolt size to allow clearance. It is typically 9/16″ for USS washers and 17/32″ for SAE washers.

What is the outer diameter of a 1/2″ washer?

The outer diameter varies by standard, with 1-3/8″ for USS washers and 1-1/16″ for SAE washers.

How thick is a 1/2″ washer?

Washer thickness varies by standard and manufacturer. Typically, USS 1/2″ washers range from 0.086 to 0.132 inch, while SAE 1/2″ washers range from 0.097 to 0.177 inch.