American Pearl · Pearl Guide

A Brief History of Pearls: Size of Akoya Pearls

The short answer

Akoya pearls range from about 2 to 10mm, and the average is about 7mm, because the Akoya oyster is small. Farmers cannot know a pearl’s size until the oyster is opened, so many Akoya strands are graduated or have a half-millimeter size range, such as 7 to 7.5mm.

Reviewed by American Pearl’s pearl specialists · Updated October 2026

	A brief history of pearls		SIZE OF AKOYA PEARLS Akoya pearls come from relatively small oysters, and as a result, the pearls themselves are typically smaller than other cultured pearls are. Average Akoya Pearl Sizes The average Japanese Akoya cultured pearl is about 7 millimeters in diameter. However, when they're harvested, they can range between 2 millimeters and 10 millimeters. Graduated Pearl Strands with Akoya Cultured Pearls Because the development of pearls depends on a natural process, it can be unpredictable. There's no way for a pearl farmer to know how large or small a pearl will be before opening the oyster, so many Akoya pearl strands feature graduated sizing. The term graduated refers to the practice of using smaller pearls on the outsides of a strand and including larger pearls in the center. Many uniform necklaces have a range of graduation of 0.5 millimeters.
	How pearls form in oysters
	How pearls are harvested
	How pearls brought to market

	Know your Akoya pearls
	Akoya Pearl Cultivation
	Akoya Pearl Harvesting
	Akoya Pearl Processing
	Akoya Pearl Evaluation

	Quality Factor One: Luster
	Luster of Akoya Pearls
	Quality Factor Two: Surface
	Surface of Akoya Pearls
	Quality Factor Three: Shape
	Shape of Akoya Pearls
	Quality Factor Four: Color
	Color of Akoya Pearls
	Quality Factor Five: Size
	Size of Akoya Pearls

	Know your South Sea pearls
	South Sea Pearl Cultivation
	South Sea Pearl Harvesting
	South Sea Pearl Processing
	South Sea Pearl Quality Evaluation
	Luster of South Sea Pearls
	Surface of South Sea Pearls
	Shape of South Sea Pearls
	Color of South Sea Pearls
	Size of South Sea Pearls

	Know your Tahitian pearls
	Tahitian Pearl Cultivation
	Tahitian Pearl Harvesting
	Tahitian Pearl Processing
	Tahitian Pearl Quality Evaluation
	Luster of Tahitian Pearls
	Surface of Tahitian Pearls
	Shape of Tahitian Pearls
	Color of Tahitian Pearls
	Size of Tahitian Pearls

	Gift Giving Occasions


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Akoya pearl sizes: common questions

What is the average size of an Akoya pearl?

The average size of an Akoya pearl is about 7mm in diameter.

How big can Akoya pearls get?

Akoya pearls can get up to about 10mm. Akoya pearls over 9mm are rare and priced accordingly. For larger pearls, look at South Sea and Tahitian pearls.

What is a graduated pearl necklace?

A graduated pearl necklace is a strand with the largest pearls at the center and smaller pearls toward the clasp. Uniform strands usually have a range of about 0.5mm, for example 6.5 to 7mm.

What size Akoya pearl should I choose?

To choose an Akoya pearl size, use our pearl size guide. As a rule, 6 to 7mm is classic and versatile, and 7.5mm and up makes more of a statement.