Bra Measurement Chart Us
Two measurements — around your ribcage under the bust, and around the fullest part of the bust — give a starting bra size. Enter them below to calculate your US band and cup size with the modern method, compare it with the traditional “+4” method, and see UK, EU, French and Australian equivalents and your sister sizes. Then use the fit checklist to fine-tune.
Bra size calculator
Bra Fit Guide Pack
Printable bra size charts (US, UK, EU, FR, AU), a sister size chart, a measuring guide, a bra fit checklist and a bra wardrobe log (Excel).
- Cup conversion (PDF/XLSX)
- Band conversion (PDF)
- Sister sizes (PDF)
- Fit checklist (PDF, DOCX)
- Wardrobe log (XLSX)
Formats: PDF, XLSX, DOCX. Instant download after payment (link valid 72 hours, up to 5 downloads). AI-assisted: the templates were drafted with AI help and reviewed and laid out by Kedop.
$3.00 USD, one-time
Secure card checkout by Stripe. Full refund within 7 days — see the refund policy and license.
How bra sizes work
A bra size has two parts. The band size (32, 34, 36…) relates to the measurement around your ribcage under the bust. The cup letter shows the difference between the bust measurement and the band: each inch of difference is one cup size. A 34C means a 34-inch band with a bust about 3 inches larger (37 inches). Because cup volume depends on the band, a C cup on a 38 band holds more than a C cup on a 30 band.
US cup size chart
| Bust − band (in) | US cup | UK cup | EU cup |
|---|---|---|---|
| 0 | AA | AA | AA |
| 1 | A | A | A |
| 2 | B | B | B |
| 3 | C | C | C |
| 4 | D | D | D |
| 5 | DD / E | DD | E |
| 6 | DDD / F | E | F |
| 7 | G | F | G |
| 8 | H | FF | H |
| 9 | I | G | I |
| 10 | J | GG | J |
US brands differ in how they name cups above D: some use DD then DDD, others DD then E and F. UK sizing adds double letters (DD, FF, GG, HH), so a UK F is not the same as a US F. Always check which system a brand uses.
Measuring for a bra
- Wear a non-padded, well-fitting bra (or none).
- Underbust: wrap the tape snugly around your ribcage directly under the bust, level all the way round, and exhale. Round to the nearest inch.
- Bust: stand straight and measure loosely around the fullest part of the bust, tape level across the back.
- Some fitters also measure while leaning forward (bust hanging) and take the larger number for fuller or softer tissue.
- Enter the numbers in the calculator.
Modern vs traditional method
The traditional “+4” method added 4 or 5 inches to the underbust to get the band size — a relic of older, less stretchy bra materials. Many fitters now use the modern method: the band is close to your actual underbust measurement, rounded to an even number. The modern method usually gives a smaller band and larger cup (for example 30E instead of 34B), which often fits better because the band provides most of a bra’s support. Try both and see which fits.
Sister sizes
Sister sizes have the same cup volume on a different band: go up a band and down a cup, or down a band and up a cup. 34C, 32D and 36B are sister sizes. If a bra’s cups fit but the band is too loose, try the sister size with a smaller band (32D). If the band is too tight but the cups fit, try the larger band sister size (36B).
How a bra should fit
- Band — level all the way round and snug on the loosest hook; you should fit about two fingers under it.
- Cups — smooth with no gaping or spilling over the top or sides.
- Centre gore — the middle panel sits flat against the breastbone in underwired bras.
- Underwire — encloses breast tissue without sitting on it.
- Straps — stay in place without digging in; they should carry only a small part of the support.
Troubleshooting fit
| Problem | Likely fix |
|---|---|
| Band rides up at the back | Band too big — go down a band (and up a cup) |
| Straps dig in | Band too loose or straps too tight |
| Cups gape | Cup too big or wrong style for your shape |
| Spilling over cups | Cup too small — go up a cup |
| Centre gore lifts away | Cups too small or too shallow |
| Wires poke under arms | Try a different shape or smaller cup width |
Worked example
An underbust of 31 inches and a bust of 36 inches: with the modern method the band rounds to 32 and the difference is 4 inches — a US 32D (UK 32D, EU 70D). The traditional method would give a 36 band and a difference of 0 — an AA cup, which would likely be far too big in the band. The sister sizes of 32D are 30DD and 34C.
When to re-measure
Measure again every six months or so, and after weight changes, pregnancy, breastfeeding, starting new exercise routines or hormonal changes. Bras also stretch with wear: a bra that fit on the loosest hook when new should still fit on the tightest hook later.
Privacy
Measurements are processed in your browser and never stored.
Frequently asked questions
How do I calculate my bra size?
Measure underbust (band) and bust; the difference in inches gives the cup — each inch is one cup size.
What does 34C mean?
A 34-inch band with about a 3-inch difference between bust and band.
What is a sister size?
A size with the same cup volume on a different band, such as 34C and 32D.
Is a US DDD the same as UK F?
No — a US DDD is roughly a UK E; UK uses double letters differently.
Should I add 4 inches to my band?
That traditional method often gives bands that are too loose; many fitters use the underbust directly.
How often should I re-measure?
Every six months or after body changes.
What is the most common bra size?
There is no reliable single answer; sizes vary widely, and many people wear the wrong size, so measuring matters more than averages.
Do sports bras use the same sizes?
Many use band and cup sizes, others S–XL; check the brand chart and prioritise a firm band.
Why does my band ride up?
The band is probably too loose; try a smaller band with a larger cup (a sister size).
Is my data stored?
No, it runs in your browser.