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What do you know about
diamonds
Explore the captivating world of diamonds. Learn about their origin, beauty, and the 4 Cs that define their quality. Welcome to the world of timeless elegance and enduring brilliance.
By Fiona, founder of Ronora Diamond. Updated September 26, 2026.
Measure your wrist just below the wrist bone and add 0.5 inch: a 6.5 inch wrist wears a 7 inch tennis bracelet. On that 7 inch bracelet, 2 mm round diamonds give about 74 stones and 2.16 carats, 3 mm diamonds about 52 stones and 5.11 carats, and 3.5 mm diamonds about 45 stones and 7.03 carats. So a 5 carat tennis bracelet uses stones of about 3.0 mm, and a 10 carat bracelet stones of about 4.1 mm. Counts are estimates: the clasp and the setting can change them by a stone or two.
Choose Bracelet, set your wrist size and the stone size in millimeters. The calculator counts the stones, adds up the total carat weight and draws the bracelet on a wrist at true scale. Switch the shape and the placement (east-west, north-south or cross) to compare designs, and calibrate once against a bank card for a true-to-life view.
Measure the longest axis and the widest axis of the face-up outline. Carat weight is estimated from those two figures and the proportions this shape is normally cut to.
A 1.00 ct round measures
6.50 × 6.50 mm
Drawn at true physical size once your screen is calibrated. Hold a ring up to the outline to judge it properly.
Hold any bank card against the bar below and drag the slider until the two match exactly. A standard card is 85.6 mm wide. Your setting is remembered on this device.
Same weight, twelve outlines. The bars are drawn to scale against each other, longest first.
Millimeter figures are for well proportioned stones cut to the ratio shown. Individual stones vary, so ask us for the exact measurements on any stone before you order. The Dutch Marquise is one of our own cuts and has no published trade chart; those figures are Ronora's working sizes.
How many round diamonds a tennis bracelet holds, and the total carat weight, for each stone size. Each column shows the wrist and the bracelet length it wears, 0.5 inch longer, with about 0.4 mm of metal between stones.
| Stone size | 5.5 in wrist (6 in bracelet) | 6 in wrist (6.5 in bracelet) | 6.5 in wrist (7 in bracelet) |
|---|---|---|---|
| 1.5 mm (0.012 ct each) | 80 stones, 0.98 ct | 86 stones, 1.06 ct | 93 stones, 1.14 ct |
| 2.0 mm (0.029 ct each) | 63 stones, 1.84 ct | 68 stones, 1.98 ct | 74 stones, 2.16 ct |
| 2.5 mm (0.057 ct each) | 52 stones, 2.96 ct | 56 stones, 3.19 ct | 61 stones, 3.47 ct |
| 3.0 mm (0.098 ct each) | 44 stones, 4.33 ct | 48 stones, 4.72 ct | 52 stones, 5.11 ct |
| 3.5 mm (0.156 ct each) | 39 stones, 6.09 ct | 42 stones, 6.56 ct | 45 stones, 7.03 ct |
| 4.0 mm (0.233 ct each) | 34 stones, 7.92 ct | 37 stones, 8.62 ct | 40 stones, 9.32 ct |
| 4.5 mm (0.332 ct each) | 31 stones, 10.29 ct | 33 stones, 10.95 ct | 36 stones, 11.95 ct |
| 5.0 mm (0.455 ct each) | 28 stones, 12.74 ct | 30 stones, 13.65 ct | 32 stones, 14.57 ct |
Counts are rounded down, and the clasp can change them by a stone or two.
The same stone sizes on larger wrists, including the 8.5 inch length that suits an 8 inch wrist.
| Stone size | 7 in wrist (7.5 in bracelet) | 7.5 in wrist (8 in bracelet) | 8 in wrist (8.5 in bracelet) |
|---|---|---|---|
| 1.5 mm (0.012 ct each) | 100 stones, 1.23 ct | 106 stones, 1.30 ct | 113 stones, 1.39 ct |
| 2.0 mm (0.029 ct each) | 79 stones, 2.30 ct | 84 stones, 2.45 ct | 89 stones, 2.59 ct |
| 2.5 mm (0.057 ct each) | 65 stones, 3.70 ct | 70 stones, 3.98 ct | 74 stones, 4.21 ct |
| 3.0 mm (0.098 ct each) | 56 stones, 5.51 ct | 59 stones, 5.80 ct | 63 stones, 6.19 ct |
| 3.5 mm (0.156 ct each) | 48 stones, 7.49 ct | 52 stones, 8.12 ct | 55 stones, 8.59 ct |
| 4.0 mm (0.233 ct each) | 43 stones, 10.02 ct | 46 stones, 10.72 ct | 49 stones, 11.42 ct |
| 4.5 mm (0.332 ct each) | 38 stones, 12.61 ct | 41 stones, 13.60 ct | 44 stones, 14.60 ct |
| 5.0 mm (0.455 ct each) | 35 stones, 15.93 ct | 37 stones, 16.84 ct | 39 stones, 17.75 ct |
Choose Bracelet in the calculator on this page for any stone size between these rows, any wrist, and any shape or placement.
For a 7 inch bracelet on a 6.5 inch wrist: the round stone size, in 0.1 mm steps, whose total comes closest to each carat target.
| Target total | Stone size | Stones | Actual total | Each stone |
|---|---|---|---|---|
| 1 ct | 1.4 mm | 98 | 0.98 ct | 0.010 ct |
| 2 ct | 1.9 mm | 77 | 1.92 ct | 0.025 ct |
| 3 ct | 2.3 mm | 65 | 2.88 ct | 0.044 ct |
| 4 ct | 2.7 mm | 57 | 4.09 ct | 0.072 ct |
| 5 ct | 3.0 mm | 52 | 5.11 ct | 0.098 ct |
| 7 ct | 3.5 mm | 45 | 7.03 ct | 0.156 ct |
| 10 ct | 4.1 mm | 39 | 9.79 ct | 0.251 ct |
On a larger wrist more stones fit, so the same target needs slightly smaller stones; on a smaller wrist, slightly larger ones. The calculator works it out for any wrist.
Lab grown diamond tennis bracelets, made to your wrist length in 9K, 14K or 18K solid gold, platinum or 925 silver. The total weight grows with the length, from about 2 ct on the dainty round to over 16 ct on the yellow radiant.
How placement changes a bracelet of elongated stones. Round stones are identical in every placement; the oval column is for stones 3 mm wide and 4.1 mm long, about 0.146 carat each, on a 7 inch bracelet.
| Placement | How each stone sits | 3 mm round stones | 3 mm wide oval stones | The look |
|---|---|---|---|---|
| East-west | Length runs along the bracelet | 52 stones, 5.11 ct | 39 stones, 5.69 ct | A sleek line of fewer, longer stones |
| North-south | Length runs across the wrist | 52 stones, 5.11 ct | 52 stones, 7.58 ct | More stones, a wider band and more carat weight |
| Cross | Tilted at 45 degrees | 52 stones, 5.11 ct | Between the two | A slanted, patterned line |
Square shapes such as princess and Asscher look the same east-west and north-south, and cross sets each stone on point, which fits fewer stones. All counts are estimates.
Wrap a soft tape measure or a strip of paper around your wrist just below the wrist bone, where a bracelet naturally sits. Keep it snug but not tight, mark the overlap and measure it flat in inches. Then add about 0.5 inch (1.3 cm). That extra length lets the bracelet move and sit flat, which is how a tennis bracelet should wear.
Ronora makes tennis bracelets in 6.5, 7, 7.5 and 8.5 inch lengths, which suit wrists of about 6, 6.5, 7 and 8 inches. If you like a looser drape, add a little more; if you want the stones to stay on top of the wrist, keep close to 0.5 inch.
A bracelet that is too short presses on the wrist and strains the clasp. One that is too long slides over the hand and catches on things. Measure the wrist you will wear it on, since the dominant wrist is often slightly larger, and tell us if you are between sizes. The full method is in our size guide.
Two numbers decide a tennis bracelet: the size of each stone and how many of them fit around your wrist. Stone size is quoted in millimeters, and total carat weight follows from it.
Small changes in stone size make large changes in carat weight, because the weight of a round diamond grows with the cube of its diameter. A 2 mm stone weighs about 0.029 carat and a 4 mm stone about 0.233 carat, 8 times as much. Twice the diameter also means only about half as many stones fit, yet the total still climbs steeply: on a 7 inch bracelet, 2 mm stones give 2.16 carats and 4 mm stones 9.32 carats, 4.3 times the weight.
That is why tennis bracelets are sold by total carat weight but chosen by look. Decide how wide a line of diamonds you want on the wrist, read the stone size off the chart, and let the carat weight fall where it falls. If you have a carat target in mind, the target chart on this page works backward from it.
On the wrist the diamonds are seen as one continuous line, so stone size reads as the width of that line.
Stones of 1.5 to 2 mm make a fine, delicate line that sits comfortably next to a watch or in a stack. At 2.5 to 3 mm the bracelet reads clearly as diamonds from across a table. Stones of 3.5 to 4 mm make a bold, substantial line, and at 4.5 to 5 mm the bracelet is a statement piece: 5 mm stones on a 7 inch bracelet add up to about 14.57 carats.
The same stones look larger on a slim wrist and finer on a broad one. On a 5.5 inch wrist a bracelet of 3 mm stones holds about 44 stones; on an 8 inch wrist it holds about 63. The line is the same width, but it covers a different share of the wrist. See a 3 mm bracelet and a 3.5 mm bracelet on a 6.5 inch wrist to compare the two side by side.
Round stones look the same whichever way they sit. Elongated shapes such as oval, pear, marquise and emerald can be set three ways, and the choice changes both the look and the count.
East-west lays each stone's length along the bracelet, so fewer, longer stones make a sleek line. North-south turns the length across the wrist: more stones fit, the band is wider, and the total carat weight rises. With ovals 3 mm wide and 4.1 mm long on a 7 inch bracelet, east-west gives about 39 stones and 5.69 carats, while north-south gives about 52 stones and 7.58 carats.
Cross tilts each stone at 45 degrees for a slanted, patterned line, and for elongated shapes the count lands between the other two. Square shapes such as princess and Asscher look the same east-west and north-south; cross turns them on point, so the diagonal runs along the bracelet and fewer stones fit. The calculator on this page redraws the bracelet for each placement.
Every count on this page follows the same rules. The bracelet is made 0.5 inch longer than the wrist, and each stone sits with about 0.4 mm of metal between it and the next. Counts are rounded down to whole stones, and the total carat weight is the count multiplied by the weight of one stone at that size.
Treat the results as close estimates, not a specification. The clasp and the safety catch take up space, and depending on the design they can remove or add a stone or two. A heavier setting with more metal between stones fits fewer. Ask us for the exact stone count, stone size and total carat weight for your wrist before you order.
Every stone is a real CVD lab grown diamond, Excellent cut, D-E-F colorless with VVS clarity, and every bracelet is made to order in Surat. See our lab grown diamond tennis bracelets, or send us your wrist size and the carat weight you have in mind.
Measure your wrist just below the wrist bone and add about 0.5 inch (1.3 cm). A 6 inch wrist wears a 6.5 inch tennis bracelet, a 6.5 inch wrist a 7 inch bracelet, and a 7 inch wrist a 7.5 inch bracelet. That half inch lets the bracelet move and sit flat without sliding over your hand.
Ronora makes tennis bracelets in 6.5, 7, 7.5 and 8.5 inch lengths, and the right one for you is your wrist measurement plus about 0.5 inch. There is no single standard that fits everyone, so measure first. A 7 inch bracelet fits a wrist of about 6.5 inches, and an 8.5 inch bracelet a wrist of about 8 inches.
A 7 inch tennis bracelet is made for a wrist of about 6.5 inches, so it is only too big if your wrist is smaller. On a 6 inch wrist it leaves about 1 inch of room and slides toward the hand, and a 6.5 inch bracelet fits better. On a 7 inch wrist it is too small, and 7.5 inches is the right length.
A 7 inch tennis bracelet holds about 93 stones of 1.5 mm, 74 of 2 mm, 52 of 3 mm or 40 of 4 mm, allowing about 0.4 mm of metal between stones. Longer bracelets hold more: an 8.5 inch bracelet of 3 mm stones holds about 63. Counts are estimates, and the clasp can change them by a stone or two.
A 1 carat tennis bracelet uses stones of about 1.4 mm: on a 7 inch bracelet, 98 of them total about 0.98 carat. With 1.5 mm stones the same bracelet holds about 93 stones and 1.14 carats. These are very fine stones, so a 1 carat tennis bracelet reads as a delicate line of light that stacks well.
A 5 carat tennis bracelet uses round stones of about 3.0 mm: a 7 inch bracelet holds about 52 of them, 5.11 carats in total. On a 7.5 inch bracelet the same stones give about 56 stones and 5.51 carats, and on a 6.5 inch bracelet about 48 stones and 4.72 carats, so the exact total depends on your wrist.
A 3.5 mm tennis bracelet is about 7.03 carats at 7 inches long, with about 45 stones of 0.156 carat each. On a 6.5 inch bracelet it is about 6.56 carats and at 7.5 inches about 7.49 carats. At 3.5 mm the line of diamonds is bold and substantial, a clear step up from 3 mm.
A 3 mm tennis bracelet is about 5.11 carats at 7 inches long, with about 52 stones of 0.098 carat each. On a 6.5 inch bracelet it is about 4.72 carats and at 7.5 inches about 5.51 carats. It is a clear everyday width that reads as diamonds without feeling heavy.
No, a 2 mm tennis bracelet is a fine, delicate line of about 74 stones and 2.16 carats at 7 inches. It suits everyday wear, sits well next to a watch and stacks with other bracelets. If you want the diamonds to read from further away, 2.5 mm (3.47 carats) or 3 mm (5.11 carats) is the next step up.
A 10 carat tennis bracelet uses stones of about 4.1 mm: on a 7 inch bracelet, 39 of them total about 9.79 carats. With 4 mm stones the same bracelet gives 9.32 carats. At this size the stones make a bold, substantial line, so check the width on your own wrist in the calculator before you choose.
