US sizing · 90 sizes · tap any cell

The ThirdLove Size Chart, Interactive

ThirdLove's chart is the broadest in mainstream US retail (AA through H, bands to 48) and adds a genuine oddity: half-cup steps, splitting each letter's inch into two. If you habitually gape in one letter and spill in the next, the half sizes are the point.

The native chart

Every ThirdLove size: tap for conversions

Half-cup sizes (A½–E½) on 30–40 bands sit between the letters shown; select bands reach I.

Two measurements in

Your size at ThirdLove

Snug underbust Relaxed bust

Same published math as the calculator (snug measure, no +4) then translated into ThirdLove’s native notation and checked against the real chart above, which lights up your cell.

Reading it

How ThirdLove sizing reads

ThirdLove’s chart reads band-then-cup in inches and US letters: the alphabet doubles after D (DD, DDD) before jumping to G. Your measured US size maps straight onto this chart with no letter translation.

From our brand dossier

How ThirdLove runs

BandBands run true to size: start with your measured band on the loosest hook.

CupCups grade generous: try your measured cup and one down.

Wire & strapsWires are average width for the system. Straps: Standard, adjustable front.

Quirk 1Half cups add roughly a third of a cup of volume: try one if you gape slightly at the apex

Quirk 2Not all sizes exist: I cups appear only in a few bands; some small combinations (30A, 32A) are absent

Quirk 3Strapless runs tight in the band

Full fit notes, style guidance and comparisons live on the ThirdLove brand page.

Honest edges

Where this chart ends

Beyond H, UK-system specialists take over: Panache and Curvy Kate in UK letters: remember the alphabet shift. And if a symptom (riding band, gaping cup, poking wire) sent you size-hunting, the fix guides decode it before you spend anything.

Answered

ThirdLove sizing: answered

Does ThirdLove run true to size?

Band: Bands run true to size: start with your measured band on the loosest hook. Cup: Cups grade generous: try your measured cup and one down. In one line: cups grade generously: your measured letter may feel roomy; one down is worth a try.

What sizing system does ThirdLove use?

Native US sizing (it reads band-then-cup in inches and US letters) the alphabet doubles after D (DD, DDD) before jumping to G. Your measured US size maps straight onto this chart with no letter translation. The interactive chart above shows every size with its US, UK, EU and FR equivalents.

What sizes does ThirdLove carry?

30–48 bands with AA–H cups in US notation. 90 sizes in the core chart. Half-cup sizes (A½–E½) on 30–40 bands sit between the letters shown; select bands reach I.

What if ThirdLove doesn't make my size?

Beyond H, UK-system specialists take over: Panache and Curvy Kate in UK letters: remember the alphabet shift. Sister sizes (same volume, different band) sometimes bridge a one-band gap: the calculator above tries them automatically before giving up.

Shop itAt HauteFlair, our sister retailer

See which brands HauteFlair carries →Shop bras by size

Opens HauteFlair’s own hub page; use your measured size there. HauteFlair is owned by the same company as Brasize.ai; that relationship never changes the sizing math, charts, or fit advice on this page. How this site makes money.

Start from the measured size

Two measurements, no inches added, sister sizes attached.

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