Quick answer
Short answer from our stud earring size guide: 5mm (about 0.5 ct per ear) is the easiest everyday size, and 6.5mm (1 ct per ear) is the classic solitaire look people notice across a table. Choose 3mm to 4mm for a second hole, and 8mm or more only when you want a statement. Shop by millimeters: that is what the eye sees.
Carat is a weight. Millimeters are what you actually see in the mirror. That is why every size below is given in mm first, with the carat weight next to it. All sizes are for round stones, the shape most people picture when they say “studs”.
Key takeaways
- Studs are sized by stone diameter in mm. Carat is weight, and moissanite is sold by DEW (diamond equivalent weight).
- 5mm to 6.5mm covers most everyday wear. 3mm to 4mm suits second and third holes.
- In diamond shops, “1 carat studs” usually means 1 ct for the pair, so about 5mm per ear. At Daellia, carat is listed per stud.
- Four prongs show the most stone, six prongs look rounder, and a bezel never snags on a sweater.
Stud earring size guide: the mm chart from 3mm to 9mm
Moissanite is about 10% lighter than diamond at the same size, so it is sold by DEW: the weight a diamond of that size would have. A 6.5mm round moissanite is about 1 ct DEW, even though it actually weighs about 0.88 ct. The chart translates between the two.
| Stone size | Carat per stud (DEW) | Pair total | How it reads on the ear |
|---|---|---|---|
| 3mm | 0.1 ct | 0.2 ct | A pinpoint of light. Made for second and third holes. |
| 4mm | 0.25 to 0.3 ct | 0.5 to 0.6 ct | Small and discreet. A good first pair or an office pair. |
| 5mm | 0.5 ct | 1 ct | The everyday sweet spot. Clearly a stone, never loud. |
| 6mm | about 0.8 ct | about 1.6 ct | Noticeable at conversation distance. |
| 6.5mm | 1 ct | 2 ct | The classic solitaire stud. Seen across a dinner table. |
| 7mm | about 1.25 ct | about 2.5 ct | Confident. Still wearable every day if studs are your main jewelry. |
| 8mm | 2 ct | 4 ct | A statement. Fills a good part of a small lobe. |
| 9mm | 3 ct | 6 ct | Evening scale. Best on larger lobes or with hair up. |
Round stones, approximate DEW. Charts round differently, so a 4mm stone can be listed as 0.25 or 0.3 ct.
Two things a chart cannot show. First, fire: moissanite throws about 2.4 times the rainbow flashes of diamond, so a 5mm stone looks lively for its size. Second, the setting: a bezel adds a thin rim of metal, so the whole stud looks a little larger than the stone inside it.
What size stud earrings look best for everyday?
Most women land between 5mm and 6.5mm for daily wear. At 5mm (0.5 ct), a stud is clearly a stone but stays quiet: it works at the office, at the gym and with glasses. At 6.5mm (1 ct), you get the classic solitaire stud, bright enough to catch the eye across a room.
Size down to 4mm if you like jewelry you forget you are wearing, or if your lobes are small. Size up to 7mm or 8mm if studs are your main piece and you rarely wear a necklace.
Torn between two sizes? The gap between 5mm and 6.5mm looks small on paper, just 1.5mm. But the face of the stone grows by about 70%, because area grows with the square of the diameter. If you want a clear step up, that is the jump that shows.
How big are 1 carat stud earrings?
“1 carat studs” can mean two very different sizes. In most diamond shops it means 1 carat total weight (ctw) for the pair, so each stone is 0.5 ct, about 5mm across. At Daellia, carat is listed per stud, so a 1 ct pair means 6.5mm on each ear and 2 ct in total.
| What the listing says | Per ear | Stone size | The look |
|---|---|---|---|
| 1 ct total weight (ctw) | 0.5 ct | about 5mm | Subtle, everyday |
| 1 ct each (2 ct total) | 1 ct | about 6.5mm | Classic solitaire |
| 2 ct each (4 ct total) | 2 ct | about 8mm | Statement |
Read the listing
ctw or tw means both earrings together. Each or per stud means one earring. Check which one a shop uses before you compare two pairs, or you may be comparing a 5mm stone with a 6.5mm one. Our moissanite carat size chart covers every shape.
What size studs for a second or third hole?
Upper piercings sit on a thinner, narrower part of the lobe, so smaller stones look more balanced there. The easy formula is to step down in size as you go up the ear: your largest stone in the first hole, then one or two sizes smaller.
| First hole | Second hole | Third hole | The effect |
|---|---|---|---|
| 6.5mm | 4mm | 3mm | Classic graduated line |
| 5mm | 3mm | none | Quiet, everyday |
| 8mm | 5mm | Pavé huggie | Evening, lots of light |
| 5mm | Marquise stud | 3mm | Mixed shapes, more modern |
Pavé huggies are the other classic second-hole choice. The Lulu huggies are lined with 58 tiny moissanites and sit close to the lobe, so they add sparkle without adding size. For a sharper line, the slim Pompadour marquise studs start at 6×3mm.
Which stud size suits your face shape and earlobes?
Your earlobe matters more than your face shape. Look in a mirror: the stone should leave a visible margin of skin around it. If it covers the lobe from edge to edge, it can look heavy, and a large stud may tip forward.
- Small lobes or petite features: 3mm to 5mm keeps everything in proportion.
- Strong jaw or angular features: round six-prong or bezel studs soften the lines.
- Soft, round features: a four-prong stud or an elongated shape, like an oval or a pear, adds a little structure.
- Short hair or hair always up: your ears are on show, so a smaller stud still gets seen.
- Long hair worn down: size up one step, since hair hides part of the ear.
A quick test at home: hold a ruler against your lobe in the mirror, find 5mm and 6.5mm, then step back to arm's length. That is the distance other people see you from.
Prong vs bezel studs: which setting should you choose?
The setting changes the look almost as much as the size. Here is how the three classic builds compare.
| Setting | Look | Good for | Watch for |
|---|---|---|---|
| 4 prongs | Most stone on show, slightly square outline | Maximum light, minimal metal | Prongs can catch on knits |
| 6 prongs | Round crown silhouette | Larger stones, a rounder look | A little more metal around the stone |
| Bezel | Clean metal rim, graphic | Busy days, sweaters, scarves | The rim covers the edge of the stone |
Three ways to wear a round stud
All three are 925 sterling silver. Sirius and Véga carry triple-layer plating (rhodium, platinum, 18K gold), and Orbe has 18K gold plating. Want real gold color that lasts? Sirius and Véga also come in 14K gold filled, from 4mm to 9mm. Our guide to gold filled vs gold plated explains the difference.
Every white Daellia stud uses D color, VVS1 moissanite, so the choice comes down to size and setting. Clean them with warm soapy water and a soft brush now and then (see jewelry care), and the stones keep their shine. New to the stone? Start with our moissanite guide.
Find your stud size
Round moissanite studs from 3mm to 11mm, D color and VVS1, in sterling silver or 14K gold filled.
Shop studsFrequently asked questions
Are 8mm stud earrings too big?
Not if you want them noticed. An 8mm round moissanite is about 2 ct DEW per ear, a clear statement size. On small lobes it covers most of the lobe, so try the ruler test first. For daily wear, most people are happier at 5mm to 6.5mm and keep 8mm for evenings.
What mm is a 1 carat moissanite stud?
A 1 ct DEW round moissanite measures about 6.5mm across. It actually weighs about 0.88 ct, because moissanite is lighter than diamond, but it is the same size as a 1 ct diamond. A pair of 1 ct studs is 2 ct in total.
Is 3mm too small for stud earrings?
For a first hole, 3mm is very discreet, more a glint than a stone at conversation distance. It is ideal for second and third holes, for stacking, or for workplaces that call for minimal jewelry. If you want your studs to be seen on their own, start at 4mm or 5mm.
What size stud earrings should I buy as a gift?
If you do not know her taste, choose 5mm or 6.5mm round studs. They suit almost every lobe and style, and they feel like a real gift. If she mostly wears small, minimal pieces, 4mm is the safer pick. If you can, check the studs she already wears and match them or go one step up.
Do bigger studs need special backs?
Larger studs stay straighter with a back that grips firmly and sits flat against the lobe. Push backs and butterfly backs both work well when they are snug. If a stud starts to tilt forward, the back has usually loosened with wear, and a new pair of backs fixes it.
Keep reading
Written by the Daellia Journal team, Paris. We write about moissanite, metals and the stories behind fine jewelry so you can buy with confidence. Read our moissanite guide or our story.
