Legacy Bra Size Estimate

This tool retains oc-bra-legacy-v1, a nonstandard two-measurement estimate. Use it only to choose a first size to try. It is not a universal US, UK, retailer, or manufacturer system, and its cup labels belong only to this named method.

Measurements and method

Select inches or centimeters, then enter a snug underbust and the circumference at the fullest part of the bust. The starting inch values are 34 in and 37 in; the centimeter fields start at 86 cm and 94 cm. Values must be positive.

For centimeter entries, the named method first assumes:

$\text{inches}=\frac{\text{centimeters}}{2.54}$

It rounds underbust to the nearest even band, subtracts that band from bust, rounds the difference to a whole-number position, and looks up the corresponding stored label from AA through K. A negative difference is held at the first label, while a difference beyond the stored list is held at the last. Those are legacy method rules, not evidence of universal sizing.

With 34 in underbust and 37 in bust, the band remains 34 and the difference is $37-34=3.0$ in. Position 3 maps to C, so the estimate is 34C. The 86 cm and 94 cm starting values also show 34C after conversion and rounding.

Try-on workflow

1. Measure without compressing the tape and note whether the values are inches or centimeters.
2. Use the estimate as the first item to try, not as a guaranteed purchase size.
3. Check the intended brand’s own chart before ordering.
4. During try-on, assess the band, cup containment, straps, and center fit together; changing one component can affect the others.
5. Re-measure rather than assuming an old label transfers between brands or styles.

Brand grading, cup shape, garment construction, and measuring practice can all change fit. This page does not claim exact sister-size volume equivalence. For another physical-size lookup, the ring-size chart likewise requires confirmation with the intended seller’s sizing system.

Inspect sensitivity without claiming a new fitted size

Keep the original underbust and bust measurements as the measured record. If a small plausible measurement change produces another legacy label, save that as an uncertainty scenario rather than a new measurement. Compare the original record with the particular garment’s sizing and fit information instead of selecting whichever hypothetical label you prefer.

Sources

• ThirdLove, Bra Size Calculator and Chart — manufacturer-specific measurement and chart context.
• Bravissimo, Bra fitting guide — manufacturer-specific fit checks and fitting service context.