Ring Blank Length Calculator
Calculate the length of flat metal strip needed to make a ring of a given size. Accounts for metal thickness using the neutral axis method.
A band wider than 6 mm has to clear the knuckle, so it needs a larger inner diameter.
Blank length
57.65mm
Blank length
2.270in
Cut to (adds 1.5 mm for the joint)
59.15mm
Neutral diameter
18.35mm
Tips
- Cut slightly long — you can always file down, but you can't add metal back.
- The recommended length adds ~1.5mm for filing the ends clean and achieving a tight solder joint.
- Anneal your strip before bending to avoid cracking, especially with sterling silver.
How it works
When you bend a flat strip of metal into a ring, the outside surface stretches and the inside surface compresses. Somewhere in the middle of the metal's thickness, there's a layer that stays exactly the same length it was when flat. This is called the neutral axis.
For a simple bend like a ring band, the neutral axis falls roughly at the midpoint of the metal's thickness. So instead of measuring from the inner or outer surface, the calculator measures from this midpoint to get the correct strip length:
blank length = π × (inner diameter + metal thickness)
The optional solder overlap adds about 1.5× the metal thickness to the length. This gives you enough extra to file both ends perfectly flat and still have a tight butt joint for soldering.
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