Bezel Strip Length Calculator
A bezel is a thin strip of metal wrapped around a stone to hold it in place, and a metalsmith needs to cut the strip to the right length. For a round stone, that length is the stone's circumference plus a small overlap allowance for the join. This bezel length calculator multiplies the stone diameter by pi to get the circumference, then adds your overlap allowance to give the total strip length to cut. The circumference is the distance around the stone, and a touch of overlap lets the ends meet cleanly for soldering without a gap. The default overlap of a couple of millimeters suits most small stones; thicker bezel stock or larger stones may need slightly more. Every figure here is computed deterministically from your inputs, so the same stone and overlap always return the same strip length. Enter the stone diameter and overlap below to cut a bezel strip to length, plan metal stock for a batch of settings, or check a pattern, with a worked example that reconciles to the calculator defaults. This covers round stones only; oval, square, and fancy shapes use that shape's own perimeter, so measure the actual perimeter for any non-round stone.
Bezel strip length equals the stone diameter times pi, plus an overlap allowance. A 10 mm round stone with a 2 mm overlap needs a 33.42 mm strip.
Bezel length formula
circumference = stone diameter x pi
strip length = circumference + overlap allowance
diameter and overlap in millimeters, pi = 3.14159
The circumference is the distance around a round stone, found by multiplying its diameter by pi. Adding a small overlap allowance gives enough strip for the ends to meet and be soldered cleanly.
Worked example
Take a round stone 10 millimeters in diameter, with a 2 millimeter overlap allowance for the join.
- Circumference: 10 x 3.14159 = 31.42 mm
- Strip length: 31.42 + 2 = 33.42 mm
The bezel strip should be about 33.42 millimeters long, which matches the calculator's default inputs exactly. Cut a little long and trim to fit if you are unsure.
Bezel Strip Length Calculator: frequently asked questions
Why add an overlap allowance?
A small overlap lets the two ends of the bezel strip meet cleanly so they can be soldered without a gap, and gives a little material to file flush. A couple of millimeters suits most small stones, with more for thicker stock or larger settings.
Does this work for oval or square stones?
No, this calculates the circumference of a round stone. Oval, square, and fancy-shaped stones need the perimeter of that specific shape instead. Measure the actual perimeter of a non-round stone and add your overlap allowance to that.
Should the bezel match the stone diameter exactly?
The strip wraps around the stone, so its length is based on the stone's circumference, not its diameter directly. The bezel height and thickness are separate choices that affect how much metal sits above and around the stone, not the strip length.
What if the stone has a girdle wider than its top?
Measure the diameter at the widest point the bezel will wrap, usually the girdle. The strip must clear the widest part so the stone seats fully, then the top edge of the bezel is pushed over to hold it.
Should I cut the strip a little long?
If you are unsure, yes. Cutting slightly long and then trimming to a perfect fit is easier than coming up short. The overlap allowance builds in some margin, but checking the wrap around the actual stone before soldering avoids waste.
Official sources
- Coin metal content and precious-metal specifications: US Mint. As at 25 June 2026.
Reviewed by the CalculatorHub team, edited by James Graham, 25 June 2026. See our methodology. This is general information, not financial, tax, legal or investment advice.