A bra structure diagram shows the components of a bra and how they connect. For designers and buyers it is a common language that helps communicate with factories. This guide explains the main parts, how they affect fit and what to specify.
Main components
- Cups: shape and support the breast, made from moulded foam, cut-and-sew fabric or knitted structure.
- Band: the main support around the ribcage, with elastic and hooks.
- Straps: carry load and adjust for fit.
- Gore (centre front): joins the cups and affects shape.
- Wings or side panels: connect cups to band.
- Closures and adjusters: hooks, eyes, sliders and rings.
- Underwire and channelling: found in wired styles.
How components affect fit
Band tension, cup depth, gore width and strap position change comfort and support. Small changes alter the result across sizes. A factory needs a clear diagram, measurements and tolerances.
Materials
Typical materials include nylon, polyester, elastane, cotton blends, foam and elastic. Ask for composition and weight, check stretch recovery and consider skin contact. See the underwear fabrics guide.
What to include in a tech pack
- Front, back and side diagrams with labelled parts.
- Measurements by size.
- Materials list with composition.
- Stitching and finishing notes.
- Label and packaging details.
- Grade rules for the size range.
Seamless and wireless alternatives
Some bras are knitted seamlessly or designed without underwire. These need different diagrams but the same discipline in specifying structure. See the seamless apparel sourcing guide.
Common mistakes
- Not specifying tolerances.
- Not testing across sizes.
- Overlooking closure strength.
Frequently asked questions
Do I need a diagram if I have a sample?
Yes, a diagram records the details.
Who creates the diagram?
Designers or the factory’s pattern team.
How do I test fit?
Use fit models and wear trials.
Start a project
See the underwear OEM/ODM private label guide and contact us via the contact page.
