How Is Silk Fabric Graded? Understanding Silk Quality Grades

Not all silk is the same quality — and understanding how silk is graded can help you make smarter purchasing decisions. Silk grading is a system used to classify raw silk and finished silk fabric based on quality, purity, and consistency. Here's what you need to know.

Why Silk Grading Matters

Silk quality varies significantly based on the silkworm's diet, the reeling process, the length and uniformity of the fibers, and the finishing treatments applied. Higher-grade silk has longer, more uniform fibers, fewer impurities, and superior luster and smoothness. Lower-grade silk may have shorter fibers, more irregularities, and less consistent quality.

Understanding silk grades helps you evaluate whether a product's price reflects its actual quality.

Raw Silk Grading: Grades A, B, and C

Raw silk (before weaving) is typically graded on a scale from A to C, with further subdivisions:

Grade A Silk (6A, 5A, 4A, 3A)

The highest quality raw silk. Grade A silk has the longest, most uniform filaments with minimal defects. Within Grade A, the number indicates quality level:

• 6A: The highest grade — exceptionally long, uniform filaments with virtually no defects. Used in the finest luxury products.
• 5A: Excellent quality with very long, uniform filaments. Used in premium silk products.
• 4A: Very good quality. Used in high-quality consumer silk products.
• 3A: Good quality. Used in mid-range silk products.

Grade B Silk

Mid-range quality with shorter filaments and more irregularities than Grade A. Used in lower-priced silk products and some industrial applications.

Grade C Silk

Lower quality with significant irregularities. Typically used for industrial purposes rather than consumer products.

What Grade Should You Look For in Silk Products?

For premium silk pillowcases, bedding, and clothing, look for products made from Grade A silk — ideally 5A or 6A. This ensures the longest, most uniform fibers that produce the smoothest, most lustrous, and most durable fabric.

Many brands don't disclose their silk grade, which is itself a red flag. Reputable brands that use high-grade silk are typically proud to share this information.

Other Quality Indicators Beyond Grade

Silk grade is just one quality indicator. When evaluating silk products, also consider:

• Momme weight: Higher momme = more silk = more durable. Look for 19–22mm for pillowcases and bedding.
• Fiber type: 100% mulberry silk is the highest quality. Avoid blended or unspecified "silk."
• Weave: Charmeuse weave provides the smoothest surface for skin and hair contact.
• Certifications: OEKO-TEX certification confirms the silk is free from harmful substances.
• Brand transparency: Reputable brands clearly state grade, momme weight, fiber type, and certifications.

The Bottom Line

When shopping for silk, look for Grade A (5A or 6A) mulberry silk at 19–22 momme with OEKO-TEX certification. These indicators together point to a genuinely high-quality product that will deliver the full benefits of silk.

At SILKSER, we use premium Grade A mulberry silk in our products. Explore our full collection and invest in silk quality you can trust.