Calculator · Approximate estimate

Breast Volume Calculator

Cup letters describe a difference in inches, not a volume — this tool converts that difference into a rough cc estimate so you can compare sizes more concretely while shopping.

Enter both measurements to continue.

Size & estimated volume
34D
Approximately 350–430cc per side

A schematic fit diagram, scaled to your cup size.

Why this is a range, not a number

We estimate a rough per-step volume increase for each cup letter, scaled by band size, since the same letter represents more tissue on a larger band than a smaller one. The result is deliberately shown as a range rather than a precise figure.

estimated volume ≈ cup index × ~150cc × (band ÷ 34)

Treat this purely as a comparison tool — useful for sensing how much more volume a sister size or a size up might represent, not as any kind of clinical measurement.

Using the estimate

What volume estimates are good for

Comparing sisters

Same volume, different band

Sister sizes should return very similar volume estimates — a useful sanity check that the relationship holds.

Comparing brands

Same letter, different actual fit

If two brands' same-letter cups feel different, a volume estimate can help explain roughly how much the actual capacity differs.

Not for

Medical or surgical use

This estimate is a shopping comparison only — not a substitute for any clinical measurement or consultation.

Not for

Precise cross-brand prediction

Cup shape and cut vary enough between brands that this estimate won't predict an exact fit, only a rough comparison.

Questions

Volume estimate FAQs

It's a rough approximation only. Shape, density and how tissue is distributed all affect real volume in ways that band and cup size alone can't capture precisely.

Because volume scales with band size — the same cup letter represents more estimated volume on a larger band than on a smaller one.

Mainly comparison — getting a rough sense of how much more volume one size holds versus another, such as when deciding between a sister size or a brand that runs differently.

No. This is a shopping-comparison estimate only, not a clinical or surgical measurement. Speak with a doctor for anything medical.

Turn a cup letter into a comparable number.

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