ThirdLove Size Chart & Half-Cup Sizing
The DTC brand that introduced half-cup sizes: memory-foam contour bras in one of the widest US size grids online.
ThirdLove in numbers
ThirdLove launched with a fit quiz and the first commercially available half-cup sizes: a half step of volume between standard letters, sold in bands 30–40. Its 24/7 collection is a memory-foam contour bra; bands run true to size, cups are forgiving, and the size grid is broad though not every combination exists.
Your measured size in ThirdLove
How this is computed: your US size read straight onto the US label, then adjusted for how ThirdLove typically grades: true bands, generous cups.
Where ThirdLove sits on the size grid
Cups AA–H (I in select bands), plus half-cup sizes A½–E½ on 30–40 bands. Not every band–cup combination exists; the largest cups usually appear on mid-range bands only.
Best for:
- Between two cup sizes
- Memory-foam contour without gaping
- Online fitting with a generous exchange window
ThirdLove bra size chart (US sizing)
Open the interactive size chart →
ThirdLove labels in United States notation. Rows are bands (US number, US equivalent in brackets); columns are cup letters as ThirdLove writes them. Each cell links to that size's guide.
| Band | AA | A | B | C | D | DD | DDD | G | H |
|---|---|---|---|---|---|---|---|---|---|
| 30 (US 30) | 30AA | 30A | 30B | 30C | 30D | 30DD | 30DDD | 30G | 30H |
| 32 (US 32) | 32AA | 32A | 32B | 32C | 32D | 32DD | 32DDD | 32G | 32H |
| 34 (US 34) | 34AA | 34A | 34B | 34C | 34D | 34DD | 34DDD | 34G | 34H |
| 36 (US 36) | 36AA | 36A | 36B | 36C | 36D | 36DD | 36DDD | 36G | 36H |
| 38 (US 38) | 38AA | 38A | 38B | 38C | 38D | 38DD | 38DDD | 38G | 38H |
| 40 (US 40) | 40AA | 40A | 40B | 40C | 40D | 40DD | 40DDD | 40G | 40H |
| 42 (US 42) | 42AA | 42A | 42B | 42C | 42D | 42DD | 42DDD | 42G | 42H |
| 44 (US 44) | 44AA | 44A | 44B | 44C | 44D | 44DD | 44DDD | 44G | 44H |
Coverage is approximate to the brand's core collections; the largest cups typically exist on mid-range bands only. US DDD is written DDD here.
Does ThirdLove run small or big?
ThirdLove bands run true to size across US bands 30–48: start with your measured band on the loosest hook, and expect it to feel snug for the first week if you are coming from an add-inches size.
ThirdLove cups grade generous from AA to H: try your measured cup and one down, and read a wrinkle at the top as the letter, not the shape, until a demi cut has been tried.
ThirdLove wires are average width for the US system. Straps: Standard, adjustable front.
What to try at ThirdLove
| Line | Notes |
|---|---|
| 24/7 Classic T-Shirt | memory-foam contour, the flagship, in half cups |
| 24/7 Classic Wireless | wireless contour |
| Classic Strapless | runs tight in the band: size the band up |
| Sport | bra-sized sport |
| Shape | Try |
|---|---|
| Full on bottom | 24/7 Classic Demi |
| Full on top | 24/7 Classic Full Coverage |
| Shallow | 24/7 Classic Wireless |
| Projected | 24/7 Classic T-Shirt in a half cup up |
| Wide-set | 24/7 Plunge |
Not sure of your shape? The fit guide explains the five shapes and how to recognize yours.
ThirdLove vs other brands
Side-by-side sizing, fit and your size in both. All comparisons →
Similar brands, different fit
The US reference for consistent grading: seven decades of pattern engineering, a broad band range and cups to H in core lines.
Minimal, unpadded and unlined by design: a DTC brand whose whole point is a broad range of thin, structured bras.
Basics-first DTC: a small line of everyday bras (lined, wireless and bralette) across a broad band and cup grid.
ThirdLove sizing: answered
What are ThirdLove half cup sizes?
Half cups (A½ to E½) add roughly a third of a cup of volume between two standard letters, sold on 30–40 bands. Try one if you gape slightly at the apex in your measured cup or spill slightly in the size below.
Does ThirdLove run true to size?
Bands run true; memory-foam cups are forgiving and soften over a few wears. The Classic Strapless runs tight in the band: go up a band.
What sizing system does ThirdLove use?
ThirdLove sizes in United States (US) convention: bands 30–48, cups AA–H (I in select bands), plus half-cup sizes A½–E½ on 30–40 bands. US labels: a US 34C is a 34C here.
Does ThirdLove run big or small?
ThirdLove bands run true to size across US bands 30–48: start with your measured band on the loosest hook. ThirdLove cups grade generous from AA to H: try your measured cup and one down.
What is my size in ThirdLove?
Start with your measured size, convert it to US notation, then apply the brand's grading: start with your measured band on the loosest hook. try your measured cup and one down. The calculator on this page does both.
What is ThirdLove best known for?
24/7 Classic T-Shirt: memory-foam contour, the flagship, in half cups. Also: 24/7 Classic Wireless (wireless contour); Classic Strapless (runs tight in the band: size the band up).
Which ThirdLove bra suits my shape?
Full on bottom: 24/7 Classic Demi; Full on top: 24/7 Classic Full Coverage; Shallow: 24/7 Classic Wireless; Projected: 24/7 Classic T-Shirt in a half cup up; Wide-set: 24/7 Plunge.
Are ThirdLove sizes the same as Wacoal?
Same notation where the systems match, different fit. ThirdLove: true band, generous cup, average wire. Wacoal: true band, true cup, average wire. Convert the label, then apply the fit notes.
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