7/8 Washer Dimensions & Size

7/8″ washers are commonly used with 7/8-inch bolts and nuts or screws in heavy construction, structural steel assemblies, industrial machinery, and large equipment installations. They are designed to distribute load, protect surfaces, and improve fastening stability under high clamping forces. Under the USS standard, a 7/8″ plain washer typically has a nominal inner diameter of 15/16″ and a nominal outer diameter of 2-1/4″, with a thickness range of 0.136–0.192 inch. While under the SAE standard, it has a nominal inner diameter of 15/16″ and a nominal outer diameter of 1-3/4″, with a typical thickness range of 0.108–0.160 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 15/16 0.931 0.968
Outer Diameter 2-1/4 2.243 2.280
Thickness Not specified 0.136 0.192
SAE Standard
Dimensions Nominal Size (in) Actual Size (in)
Min Max
Inner Diameter 15/16 0.931 0.968
Outer Diameter 1-3/4 1.743 1.780
Thickness Not specified 0.108 0.160
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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. While SAE (Society of Automotive Engineers) washers are typically smaller and thinner, designed for more compact and tighter fit assemblies.

What size is a 7/8″ washer?

The size of a 7/8″ washer depends on the standard. Under the USS standard, it typically has a nominal inner diameter of 15/16″ and a nominal outer diameter of 2-1/4″. Under the SAE standard, it usually has a nominal inner diameter of 15/16″ and a nominal outer diameter of 1-3/4″.

What is the inner diameter of a 7/8″ washer?

The inner diameter is larger than the bolt size to allow clearance. It is typically 15/16″ for both USS and SAE washers.

What is the outer diameter of a 7/8″ washer?

The outer diameter varies by standard, with 2-1/4″ for USS washers and 1-3/4″ for SAE washers.

How thick is a 7/8″ washer?

Washer thickness varies by standard and manufacturer. Typically, USS 7/8″ washers range from 0.136 to 0.192 inch, while SAE 7/8″ washers range from 0.108 to 0.160 inch.