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.

测量并推荐尺码

输入自己的数据，系统会匹配最接近的参考行，再按品牌尺码表确认。

怎么测量

文胸

下胸围水平贴合身体，保持贴身但不勒。
胸围量最丰满的位置。
用胸围和下胸围差值看罩杯，再核对品牌算法。

你的数据

单位

下胸围

胸围 / 胸部

最接近参考

先输入你已有的数据。只填一部分也可以，字段越完整越接近。

仅作参考。版型、宽度、材质、余量和品牌规则都会影响最终选择。

测量细节

使用软尺，穿无衬垫或轻薄内衣测量。软尺保持水平，正常呼吸，不要刻意收紧。

下胸围 / Band

软尺绕过胸下、文胸下围所在的位置，贴合身体并保持一圈水平。

多数尺码体系会用它来确定 band 数字。

胸围 / Overbust

软尺绕过胸部最丰满的位置，不要压扁胸部，也不要让背后下坠。

站在镜子前测更容易保持水平。

罩杯差值

胸围减下胸围得到差值，再用差值去参考罩杯。不同地区 D 以后写法会不一样。

罩杯字母不能脱离 band 单独理解。

合身检查

下围应提供主要支撑，杯面不空杯也不压杯，肩带不应承担全部重量。

如果下围合适但杯量不对，可以再看姐妹尺码。

下胸围 / 围度参考

先用下胸围对照常见 US、UK、EU、FR 围度标签，再结合品牌的取整方式确认。

下胸围	下胸围 (cm)	US 围度	UK 围度	EU 围度	FR 围度
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

罩杯 A / B / C / D 参考

用胸围减下胸围得到罩杯差，再对照 A、B、C、D 以及更大的罩杯标签。罩杯字母不能脱离围度单独判断。

差值	差值 (cm)	US 罩杯	UK 罩杯	EU 罩杯
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.

常见问题

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.