Bra Size Calculator

A bra measurement calculator combines an underbust circumference and a full-bust circumference to suggest a band-and-cup label. The result is a starting size to try, rather than a guarantee of fit. Two measurements cannot describe every difference in shape, garment stretch or cup construction.

This tool uses a direct-measurement method with no traditional +4-inch adjustment. US, UK and EU results share that same estimate, with regional labels taken from an explicit conversion table. It does not silently switch fitting methods when you change country.

Your entries stay in the page’s browser memory. No account, photos, name, age or other personal information is needed. Reloading clears your entries; copying or printing creates a report only when you choose that action.

Full bust is the circumference around the fullest part of the bust. Let the tape rest against your body without pulling tightly. Check that the tape has not slipped into a diagonal position, then take a second reading if the first was difficult to hold steady.

The full-bust number is an input measurement, not a cup letter. Cup estimation also needs a band reference. A bust size calculator that asks for only one circumference cannot establish the band-and-cup relationship used here.

Underbust is measured around the ribcage immediately below the bust. Keep the tape firm enough to stay level while remaining comfortable. Do not add inches before entering the measurement; the calculator’s band selection is shown separately.

Record the actual tape reading rather than substituting your current bra’s label. A band label is a clothing size and may not equal an unstretched garment circumference or a brand’s recommended tape measurement.

In this documented method, difference = full bust in inches − selected US/UK reference band. The difference is rounded to the nearest whole inch, with half-inch ties going upward. The rounded position selects a cup from the regional sequences below.

For an underbust of 32 inches and bust of 36 inches, the selected reference band is 32. The difference is 36 − 32 = 4 inches, producing 32D in US or UK labels and the chart equivalent 70D in EU labels.

AA is assigned to nonnegative differences below 0.5 inches. This chart ends at a rounded difference of 10 inches: UK GG / US J / EU J. A larger difference, or a bust smaller than the rounded band, gives an unsupported-method message instead of an invented label.

The direct-measurement band rule selects the nearest even US/UK band number. A measurement of 32.4 inches selects 32; a measurement of 33 inches is a tie and selects 34. No +4 adjustment is added.

This implementation supports US/UK bands 30 through 46, corresponding to underbust measurements from 29 up to, but not including, 47 inches under this rounding rule. These are the limits of the selected reference chart, not limits on which sizes exist.

Different fitting methods may round upward, add a band allowance or use separate centimeter ranges. A result from another bra calculator may therefore differ even when both tools receive the same measurements. Compare the assumptions before comparing labels.

US and UK band numbers match in this chart, while the EU band sequence uses five-number steps. For example, US/UK 32 maps to EU 70. Cup letters diverge above D: UK DD maps to US DD and EU E; UK E maps to US DDD and EU F.

To use the International Bra Size Converter, choose your current system, enter the label, then choose the destination. A UK 32FF becomes US 32H or EU 70H under this chart. The converter also shows neighboring sister sizes in the destination system.

US E and F can have different meanings in different brand charts. This tool accepts its displayed US DD and DDD labels and does not guess ambiguous alternatives. Unsupported bands or cups produce a clear explanation.

Sister sizes adjust band and cup together to suggest nearby combinations with approximately similar cup volume. One band step down goes one cup position up; one band step up goes one cup position down. UK 32D therefore has neighboring sister sizes 30DD and 34C.

A D cup does not describe one fixed volume independently of band size. Sister-size calculations must follow the regional sequence, including entries such as DD and FF, rather than changing a letter alphabetically. At the chart edges, an unavailable neighbor is labeled outside the supported chart.

Fit can still change when the band changes. For more context, see Bravissimo’s sister-size explanation.

Check that the band stays level, cups contain the bust without cutting in or leaving unwanted gaps, and straps feel comfortable. If there is an underwire, it should not press into breast tissue. Move and sit down to check comfort rather than judging the size label alone.

If the cups feel close but the band needs adjusting, a neighboring sister size can be a starting point. If the cup shape itself does not suit you, another style may be more useful. A fitting specialist can help interpret the result when measurements and comfort do not agree.

A size label does not fully describe a garment’s construction. Materials, stretch, cup shape, padding and the maker’s sizing method can affect fit. Treat a calculated result and an international conversion as a guide for trying sizes.

Use the manufacturer’s current chart for the garment you plan to buy. You can return to the Health & Fitness calculator hub to explore the tools available on CalcVibes.