Replacing a Wire?
Get the Right Length.
Whether your underwire poked through the fabric or you're sewing a bra from scratch, you need the exact wire length for your size. Select your band and cup to get an estimated underwire length in millimetres.
- ✓ Results in under a minute, no sign-up needed
- ✓ Estimated in millimetres, the standard wire unit
- ✓ Useful for repairs and DIY sewing
Estimate your underwire size
Select your band and cup size.
How Underwire Size Is Estimated
Underwire length depends mainly on the band (the wire spans your ribcage) with a smaller adjustment for cup size, since a larger cup needs a slightly longer wire to fully cradle the tissue. Manufacturers label wires in millimetres, and sizes are rarely identical between brands, so treat this as a starting point for ordering replacement wires.
How to Measure Your Old Wire Instead
- Remove the wire from the casing carefully, cutting the stitching if needed.
- Lay it flat on a hard surface.
- Measure end to end along the wire's curve using a flexible tape or string.
- Round to the nearest millimetre most replacement wire packs are sold by this measurement directly.
Frequently Asked Questions
Do all brands use the same wire length for my size?
No wire shape and length vary by brand and style, even within the same labelled size.
Can I reuse a wire from a different size bra?
Only if the measured length and curve shape match closely otherwise it will sit incorrectly.
What if my wire keeps poking through?
That usually means the wire has bent out of shape or the casing has worn through replacing both is more reliable than patching the fabric alone.