Wrap the tape directly under the bust where the band sits. Keep it snug and level all the way around.
This anchors the band size in most systems.Best for turning bust and underbust measurements into a practical starting size.
Bra Size Calculator
Enter your bust and underbust measurements to estimate a starting bra size across US, UK, EU, and FR systems, then compare the result with the brand's own chart.
Measure and get a size suggestion
Use your own measurements to find the closest reference row, then confirm with the brand chart.
How to measure
Bra- Measure underbust level and snug.
- Measure bust at the fullest point.
- Use the difference for cup reference, then check the brand method.
Your measurements
Closest reference
Enter the measurements you have. A partial result is okay, but more fields give a better match.
Reference only. Product cut, ease, width, material, and brand rules can change the final size.Measurement details
Use a soft tape and a non-padded or lightly padded bra. Keep the tape level and breathe normally.
Measure around the fullest part of the bust without flattening the tissue.
A mirror helps keep the tape from dipping in the back.Use the difference between bust and underbust as the cup reference, then check the regional cup system.
Cup letters are not absolute volumes by themselves.The band should support, cups should not gap or spill, and straps should not carry all the weight.
Sister sizing can help when the band fits but cup volume feels off.Band Size Reference
Start with the underbust measurement to compare common US, UK, EU, and FR band labels.
| Underbust | Underbust (cm) | US band | UK band | EU band | FR band |
|---|---|---|---|---|---|
| 21-22 in | 53-57 cm | 26 | 26 | 55 | 70 |
| 23-24 in | 58-62 cm | 28 | 28 | 60 | 75 |
| 25-26 in | 63-67 cm | 30 | 30 | 65 | 80 |
| 27-28 in | 68-72 cm | 32 | 32 | 70 | 85 |
| 29-30 in | 73-77 cm | 34 | 34 | 75 | 90 |
| 31-32 in | 78-82 cm | 36 | 36 | 80 | 95 |
| 33-34 in | 83-87 cm | 38 | 38 | 85 | 100 |
| 35-36 in | 88-92 cm | 40 | 40 | 90 | 105 |
| 37-38 in | 93-97 cm | 42 | 42 | 95 | 110 |
| 39-40 in | 98-102 cm | 44 | 44 | 100 | 115 |
| 41-42 in | 103-107 cm | 46 | 46 | 105 | 120 |
| 43-44 in | 108-112 cm | 48 | 48 | 110 | 125 |
| 45-46 in | 113-117 cm | 50 | 50 | 115 | 130 |
| 47-48 in | 118-122 cm | 52 | 52 | 120 | 135 |
| 49-50 in | 123-127 cm | 54 | 54 | 125 | 140 |
| 51-52 in | 128-132 cm | 56 | 56 | 130 | 145 |
Cup Size Reference
Use bust minus underbust to read A, B, C, D and extended cup labels. Cup letters should always be paired with a band size.
| Difference | Difference (cm) | US cup | UK cup | EU cup |
|---|---|---|---|---|
| 1 in | 2.5 cm | A | A | A |
| 2 in | 5 cm | B | B | B |
| 3 in | 7.5 cm | C | C | C |
| 4 in | 10 cm | D | D | D |
| 5 in | 12.5 cm | DD/E | DD | E |
| 6 in | 15 cm | DDD/F | E | F |
| 7 in | 17.5 cm | G | F | G |
| 8 in | 20 cm | H | FF | H |
| 9 in | 22.5 cm | I | G | I |
| 10 in | 25 cm | J | GG | J |
| 11 in | 27.5 cm | K | H | K |
| 12 in | 30 cm | L | HH | L |
| 13 in | 32.5 cm | M | J | M |
| 14 in | 35 cm | N | JJ | N |
How to Use the Bra Size Calculator
Choose inches or centimeters, measure directly under the bust for the underbust value, and measure around the fullest part of the bust. Enter both values without pulling the tape too tightly. The calculator maps the measurements to a practical band and cup reference rather than making a body-shape assessment.
How Band and Cup Size Are Estimated
The band estimate starts with the underbust measurement. The cup estimate uses the difference between bust and underbust measurements. Because regional labels and brand rounding rules differ, the result includes multiple sizing systems and should be checked against the exact product chart.
US, UK, EU, and FR Bra Size Results
US and UK band labels are commonly shown in inches, while EU and FR labels use different numeric conventions. Cup progressions can also diverge after D. Treat the combined band and cup result as a translation aid when comparing international stores, not as a universal conversion guarantee.
Check Fit Before Buying
A calculated size cannot account for every brand, garment construction, material, or fit preference. Confirm that the band remains level and comfortable, the cup edge sits smoothly, and the product's return policy is suitable. For pain, post-surgery needs, pregnancy, or medical concerns, consult a qualified professional.
Related Size Tools
Continue with closely related tools instead of jumping through an unrelated directory.
Bra Size Chart
Best for understanding how band and cup references work together.
Cup Size Chart
Best for comparing cup letter systems after a band size is already known.
Clothing Size Chart
Best for explaining the difference between body measurements and apparel labels.
Size Chart Generator
Best for merchants who need a product-page size chart quickly.
FAQ
What measurements do I need for the bra size calculator?
You need an underbust measurement and a bust measurement taken around the fullest part of the bust.
Can I calculate bra size in centimeters?
Yes. Select centimeters before entering the measurements; the calculator converts them for the same reference logic.
Does the calculator show international bra sizes?
Yes. It returns starting references for common US, UK, EU, and FR band and cup labels.
Is the calculated bra size exact for every brand?
Use the result as a sizing reference, then check the brand or seller chart before buying. Materials, fit preference, country labels, and manufacturing tolerances can change the best choice.