Aaron Graves, PhDude (Replica)

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bra measurement calculator uk

Posted on February 16, 2026 by Admin

UK Bra Size Calculator

Enter your underbust and full bust measurements to estimate your UK bra size (for example: 32F, 34DD, 36G).

Measure snugly around your ribcage, directly under your bust.
Measure around the fullest part of your bust while wearing a non-padded bra.

Finding the right bra size can be frustrating, especially when different brands, styles, and fabrics fit a little differently. This UK bra measurement calculator gives you a practical starting point using your underbust and full bust measurements. Use it as your baseline, then refine your fit based on comfort and support.

How UK bra sizing works

UK bra sizes combine a band size (the number) and a cup size (the letter). The band size is related to your ribcage measurement, while cup size is based on the difference between your full bust and your band size.

  • Band: 28, 30, 32, 34, 36, 38, and so on.
  • Cup letters (UK): A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, K...
  • Example: In 34F, “34” is the band and “F” is the cup.

How to measure yourself at home (UK method)

1) Underbust

Wrap a soft tape measure around your ribcage, just under your bust. Keep the tape level and snug. Breathe out gently before reading the number.

2) Full bust

Measure around the fullest part of your bust with the tape level all the way around. Stand naturally and avoid pulling the tape too tightly.

3) Use consistent units

You can use inches or centimetres. The calculator converts measurements automatically.

For best accuracy, measure twice and use the average. If possible, ask someone to help keep the tape straight across your back.

Understanding your result

Your calculator result is an estimated UK size. It is common to try two or three nearby sizes because:

  • Some bras run tighter or looser in the band.
  • Balcony, plunge, full-cup, and sports bras all fit differently.
  • Breast shape and tissue distribution can affect cup fit.

Try sister sizes when needed

If the cup feels right but the band feels too tight, go up a band and down a cup letter (for example, 34F to 36E). If the band feels too loose, go down a band and up a cup (for example, 34F to 32FF).

Quick bra fit checklist

  • Band: Firm and level around your body; should not ride up.
  • Cups: No spilling over the top or sides; no major gaping.
  • Centre gore: Lies flat against your chest (for most wired bras).
  • Straps: Supportive but not digging in (most support comes from band).
  • Comfort: No pinching, rubbing, or painful pressure points.

Common UK cup progression

UK cup lettering is not always linear like US systems. In UK sizing, double letters are standard in many ranges:

A → B → C → D → DD → E → F → FF → G → GG → H → HH → J → JJ → K

Frequently asked questions

Is this calculator accurate?

It is accurate as a starting point. Final fit depends on brand pattern, bra style, and personal comfort.

Can I use this for sports bras?

Yes, as a base size. But many sports bras use compressed sizing (S, M, L) or specific high-support fits, so check each brand’s chart.

What if I’m between sizes?

Try both nearby sizes. For example, between 34E and 34F, test both and compare cup containment and band comfort.

How often should I re-measure?

Every 6–12 months, or sooner after weight change, pregnancy/postpartum changes, hormonal shifts, or if your bras no longer feel right.

Final note

A well-fitted bra improves comfort, posture, and confidence. Use the calculator above to find your likely UK bra size, then test nearby options and choose the one that feels best for your body.

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