American Pearl · Pearl Guide

A Brief History of Pearls: Quality Factor Five : Size

The short answer

Pearls are measured by diameter in millimeters, from under 1mm to more than 20mm. Size is not a measure of quality, but it drives price: with every other factor equal, a larger pearl is worth more. The most popular size for a pearl necklace is 7 to 7.5mm.

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

	A brief history of pearls		QUALITY FACTOR FIVE: SIZE An important factor in determining the quality of a pearl is its size. It's difficult for pearl farmers to cultivate large, high quality pearls. Typically, a large, high quality pearl is more valuable than a small high quality pearl. How Are Pearls Measured? A pearl is measured in millimeters through its diameter. The smallest pearls can be smaller than 1 millimeter in size, while the largest can be bigger than 20 millimeters in size. Does a Pearl's Size Have Anything to Do With Value? A pearl's size has nothing to do with its quality, but it does have quite a bit to do with its value. With all other quality factors being equal, larger pearls are more valuable than smaller pearls are. Most Common Pearl Sizes The most popular pearl size is between 7 and 7.5 millimeters. Pearls larger than 7 millimeters cost more than their smaller counterparts do.
	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


	Previous Next

Pearl size: common questions

How are pearls measured?

In millimeters across the diameter. Strands are described by a half-millimeter range, such as 7 to 7.5mm.

Does a bigger pearl mean better quality?

No. Size does not change quality, but larger pearls are harder to grow, so a large pearl of the same quality costs more.

What size pearl necklace is most popular?

7 to 7.5mm. Pearls above 7mm rise in price quickly. See which pearl size is right.

Shop pearls by type

Akoya · Japan6 x 6.5mm White Akoya Pearl Necklace$1,150

South Sea · Australia10 x 11mm White South Sea Baroque Tin Cup Necklace$2,500

Tahitian · French Polynesia11 x 13mm Tahitian Baroque Pearl Necklace$835

Akoya · Studs7mm Akoya Pearl Stud Earrings$415

Akoya pearls South Sea pearls Tahitian pearls

Family-owned since 1950Complimentary insured shipping30-day returnsGIA reports on select strands

Still deciding? Speak with a pearl specialist at 1-800-847-3275, or browse all Pearl Answers.

← Back to the Pearl Guide