Jewellery tools
Pearl Size Chart (2026): Compare Freshwater, Akoya, Tahitian & South Sea Sizes
Millimetres mean nothing until you can see them. A 7 mm pearl and a 10 mm pearl sound close — but the 10 mm one has roughly three times the volume, which is why it costs several times more and looks like a different piece entirely. Pick a type and slide the size below to see each pearl at true relative scale, next to something you already know the size of.
8 mm Freshwater — about a green pea.
The classic range: everyday studs and the standard 7–8 mm strand.
This size is within the usual Freshwater range (2–15 mm; most common 6–10 mm).
The most affordable type and the widest size range — the usual starting point for everyday studs and first strands.
The circle is drawn to scale within this tool (9 px per mm), so sliding from 6 mm to 12 mm shows the real doubling in size — which is why price jumps so fast with diameter.
Usual size range by pearl type
Every pearl type has a size it can and cannot reach — the oyster sets the limit. If a listing breaks the range below, treat it as a warning sign, not a bargain.
| Type | Size range | Most common | Known for |
|---|---|---|---|
| Freshwater | 2–15 mm | 6–10 mm | Best value, widest colours — white, pink, peach, lavender |
| Akoya | 2–10 mm | 6–9 mm | Classic round white pearl, sharpest lustre |
| Tahitian | 8–16 mm | 9–13 mm | Naturally dark, peacock and green overtones |
| South Sea | 8–20 mm | 10–15 mm | Largest type — white/silver or golden, satiny glow |
Which size for which piece?
- Studs, everyday: 6–8 mm. Light, discreet, and the size most people mean by “pearl earrings”.
- Studs, statement: 9–11 mm. Needs a larger lobe and a confident setting — usually Tahitian or South Sea.
- Pendants: 8–12 mm. The single-pearl sweet spot: big enough to be the focal point, small enough to wear daily.
- Classic strand: 7–8 mm. The bridal and “first strand” standard.
- Bold strand: 9–12 mm. Formal and attention-getting — and the matching cost climbs fast, because every pearl in the strand must be the same size.
Size is only one of five value factors
A big dull pearl is worth less than a smaller bright one. Before you pay for size, check the other four: lustre (how sharp the reflection is), surface (how clean it is up close), shape (round commands the premium) and matching (on strands and pairs). Our own buying guide walks through all five with photos, so you can judge a listing before you pay:
The Pearl Buying Guide ($14.99) — the full 26-page guide, including the size, lustre and surface checklists. (Disclosure: this is our own product.)
Buying for Christmas? The same checks apply to gifts — our Christmas Pearl Gift Guide ($9.99) covers which sizes and types suit each recipient, from first pearls to milestone gifts.
Frequently asked questions
What is a good pearl size for everyday earrings?
6–8 mm is the everyday sweet spot for studs: visible, light, and easy to wear daily. 7–8 mm is the classic size — the one most first-time buyers picture when they think of pearl earrings. Below 6 mm reads as delicate; above 9 mm reads as a statement.
What size pearls are in a classic pearl necklace?
The classic strand is 7–8 mm, usually Akoya or freshwater. A 6–7 mm strand looks daintier and suits smaller frames; 8–9 mm is bolder and more formal. Strands above 10 mm are almost always South Sea or Tahitian, and the price rises steeply with each millimetre because large, round, well-matched pearls are rare.
How big do South Sea pearls get?
South Sea pearls range from about 8 mm to 20 mm, with 10–15 mm the most common. They are the largest cultured pearl type because the Pinctada maxima oyster is the largest pearl-producing oyster. A 15 mm+ South Sea pearl is a genuinely rare piece.
Can Akoya pearls be 12 mm?
Essentially no. Akoya pearls range from about 2 mm to 10 mm, most commonly 6–9 mm, and anything over 10 mm is exceptional. A listing that calls a 12 mm pearl 'Akoya' is either mislabelled or misrepresenting another type — usually freshwater or South Sea.
Does a bigger pearl always cost more?
Within the same type and quality, yes — and not linearly. A 9 mm pearl can cost several times a 7 mm pearl of the same quality, because the oyster must survive longer and the chance of a round, clean, high-lustre result falls as size rises. But size is only one of the value factors: lustre, surface cleanliness, shape and matching matter as much.
Size ranges checked against GIA's pearl-type guide and Pearls.jp's type pages on 2026-11-09. Everyday comparisons are approximate; coin diameters are exact (US dime 17.91 mm, US penny 19.05 mm). Pearl sizes are measured in millimetres of diameter.