Jeweler's Tools — Stone Counts, Sizes and Tolerances
Free, no sign-up, no email. Everything below answers the same question from a different angle: how many stones does this piece take, in what size, and can I actually order them? The arithmetic is published alongside every tool so you can check it yourself.
Quick stone count
Pick what you're making and the sizes you're working to.
Reference tables
- Melee size chart — millimetre to carat to stones per carat, for every shape we cut. The one conversion table you'll keep open.
- mm to carat chart, all 14 shapes — weight per stone and stones per carat for every melee size, plus 0.5–10 ct sizes in millimetres.
- Halo stone counts — worked counts for 0.5 to 4 ct centres, single and double halos, and fancy-shape outlines. A single halo is almost always 16–22 stones; the melee size is the real decision.
- Tennis bracelet, eternity band and riviera counts — a 7-inch bracelet is about 48 stones at 3 mm; eternity bands by US ring size; rivieras at 16, 18 and 20 inches.
- Choosing side stones — sizing by weight and by width, which shapes pair with which centre cuts, and the height mistake that costs a redraw.
- Setting type and tolerance — which settings need the tightest calibration, and why a fixed-diameter setting bur makes ±0.1 mm the number that matters.
When the arithmetic isn't the problem
Sometimes you don't have a size to put into a calculator — you have a picture. Send it. We lay the actual stones out beside your centre stone, photograph and film them, and send you the layout to approve before you pay.
How ordering by design works →
Sizes you can order against
Every count above is only useful if the size exists. We calibrate to ±0.1 mm and cut these standard steps: round melee from 0.7 mm, and 13 fancy shapes sold by the stone. Sizes off the standard steps are cut to order, usually a few working days.
Baguette · Trapezoid · Tapered baguette · Pear · Marquise · Oval · Emerald · Princess · Asscher · Radiant · Cushion · Heart · Trillion · Triangle
Round melee by size: 1.0 mm · 1.2 mm · 1.3 mm · 1.5 mm · 2.0 mm · 2.5 mm · 3.0 mm — stone counts, prices and what each size is used for.
Wholesale prices, listed by shape · Calibration & matching guarantee · Ask Leilei on WhatsApp
Frequently asked questions
Is there a free calculator for how many melee stones a piece needs?
Yes. Caratura's tools page has a free, no-sign-up stone count calculator for halos, eternity bands, tennis bracelets, rivieras and pave rows, plus reference tables for melee sizes, stone counts, side stone sizing and setting tolerances. The formula behind each result is shown so you can check it.
How do I know the size I calculated can actually be supplied?
Caratura calibrates to plus or minus 0.1 mm and cuts standard steps from 0.7 mm in round, plus 13 fancy shapes sold by the stone. Sizes off the standard steps are cut to order, usually adding a few working days; some non-standard dimensions need a mould, and the charge is confirmed before cutting.