Accurate Bra Size Calculator with Charts, Converter and the Guide

Several measurements will help you calculate a perfect bra size for you.

Our site provides an online calculator to help you with the task of working out the perfect sizes for your bra’s cup and band. It will also adjust the calculations to the different size systems, like the US, UK, and others. You must only take correct measurements, strictly according to the instructions above, and fill them in the corresponding fields, specifying the measurement units (inches or centimeters).

Table of contents:

Bra Size Calculator (above)
How to Measure Your Bra Size at Home Properly
1. Simple Way
  1. Underbust+4 Method
  2. Underbust+0 Method
2. Bra Measurement Guide for the Advanced Calculator
How to Fit a Bra
Bra Band Size Chart
Bra Cup Size Chart
Conclusion

How to Measure Your Bra Size at Home Properly

There are two do-it-yourself ways to take the correct measurements at home – the simple and the advanced. To do it the simple way, you need to take two measurements, namely the snug underbust and the standing bust. And there are two simple systems for measuring your bra size, namely the Underbust Plus Four and the Underbust Plus Zero. Let us have a closer look at all of them one by one in the following sections.

Simple Way

First, you must take the two essential measurements which you will need to make correct calculations of your bust size by yourself at home.

Standing Bust. Take the measurements of your breasts while standing or sitting up fully erect, and again, the tape should be parallel to the ground. Likewise, do not squeeze your breasts with it too tight, and do not let it hang loose either.

Snug Underbust. Place the tape comfortably under your bust, making sure it is in a perfectly horizontal position. You should feel as comfortable as you would like to do when you wear the bra. The tape should rest firmly under your breasts, but it must not press the skin too tight.

Underbust+4 Method

This system for measuring your bra band and cup sizes is quite common in the United States and Great Britain, especially on virtual markets, like Amazon. It is also quite popular among the most reputable online fashion brands, such as Natori and Calvin Klein.

To find your band size, take a snug underbust measurement in inches, round it to the nearest even number, and add 4 to it. For instance, if your snug underbust comes to 29.5, you round it to 30, and adding 4 to it gives you a band size of 34 inches.

To find your bra cup size, take a comfy measurement under the breast, subtract it from the measure of your bust when standing or sitting up fully erect, and find your cup size in the following table.

Cup Size Chart for US⁺⁴/UK⁺⁴
(swipe ↔)
in	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29
US	AA	A	B	C	D	DD/E	DDD/F	DDDD/G	H	I	J	K	L	M	N	O	P	Q	R
UK	AA	A	B	C	D	DD	E	F	FF	G	GG	H	HH	J	JJ	K	KK	L	LL	M	MM	N	NN	P	PP	Q	QQ

For instance, suppose your bust measurement when standing or sitting up fully erect is 35.4, and you feel most comfy under the breast at 29.5 inches. The difference is 35.4 - 29.5 = 5.9 inches, which corresponds to the cup size B, both in Great Britain and the States.

Let us have a look at another example of calculating both band and cup sizes. Suppose you feel comfy under the breast at 31, and your bust measurement when standing or sitting up fully erect comes to 37.

1. First, take 32, as it is the nearest even number to 31, add 4 to it, and you get 36 inches.
2. Next, subtract 31 from 37, and you get 6.
3. Finally, look up 6 in the table above.

Thus, your band size is 36 inches, and your cup size is C, both in Great Britain and the States.

Underbust+0 Method

Another measurement system to figure out your bra size.

Measure your band size by taking the nearest even number to your comfy under the breast,
Subtract the snug underbust from the standing bust, and
Look up your cup size in the following table.

Cup Size Chart for US⁺⁰/UK⁺⁰
(swipe ↔)
in	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26
US	AA	A	B	C	D	DD/E	DDD/F	DDDD/G	H	I	J	K	L	M	N	O	P	Q	R
UK	AA	A	B	C	D	DD	E	F	FF	G	GG	H	HH	J	JJ	K	KK	L	LL	M	MM	N	NN	P	PP	Q	QQ

For instance, suppose you feel comfy under the breast at 29.5, and your bust measurement when standing or sitting up fully erect comes to 35.4. The nearest even number to 29.5 is 30. That is your band size. And 35.4 – 29.5 = 5.9, which corresponds to the cup size DD in the United Kingdom and Australia and DD/E in the States.

As you can see, the game can be quite gripping, especially if you have completed a uni course on Applied Calculus and have a calculator and all the charts and tables at hand. You might even forget the shopping. Otherwise, if you want to make it quick and without any hassles, all you must do is enter the data in our online calculator (simple mode), and you will know your sizes in a split second.

Bra Measurement Guide for the Advanced Calculator

You can use our online calculator of the bra sizes (advanced mode) to find a size that fits you better. It is, in fact, the most sophisticated tool available online to determine the correct sizing of your bra conveniently and quickly. This section provides the instructions for proper use of it. Just make sure you follow them precisely and accurately.

Loose Underbust. Measure your chest just under your breasts with the tape parallel to the floor and barely touching your skin.

Snug Underbust. This bust measurement replicates its counterpart for the simple calculator.

Tight Underbust. Tighten the measurement tape just under your breasts as much as possible, exhaling fully beforehand.

Standing Bust. This measurement replicates its counterpart for the simple calculator.

Leaning Bust. Take it while bending over 90 degrees, with the tape being perfectly straight and barely touching your breasts.

Lying Bust. Take it while lying on your back, with the tape being perfectly straight and barely touching your breasts. You might want to use a mirror for taking this measurement properly – many women find that it helps to keep the measurement tape at the right angle to the floor.

Note: you should not squeeze your breasts with the tape when you take measurements in this position. In other words, the measurement tape must embrace your breasts gently without changing the way they fall naturally for you when you are lying flat.

Note: remember that calculating your bra size will not be enough. Most probably, you will also have to try the sizes above and below the one you work out this way before you can determine the size that fits you perfectly. Moreover, the perfect fit also depends on the bra’s shape, and the bra sizes vary across the brands, so some of them might still not fit well even after you have done all the size calculations correctly.

Note: many women, especially the ones with small chests, often disbelieve their cup sizes calculated this way because they do not account for the cup size’s variable correlation with the band size. In other words, this measurement says nothing on its own because the cup size does not remain constant, and its ultimate value depends on the size of the bra’s band too.
Moreover, when measuring a cup, they do not bend over to put the entire breast into it. When you try a bra on, you must lean forward and put all your so-called sideboobs into the cups.
However, you can avoid all these mistakes by following our guide precisely and accurately. And you should never ignore our instructions just because you cannot believe the size you have worked out using our online bra size calculator.

How to Fit a Bra

We must consider each part of the bra to check whether it fits well. These parts include the cups, bands, straps, gore, and wire. The gore refers to the piece that rests on your chest and holds the cups together.

The table below explains how to choose a bra that sits well and what you can do if it does not.

swipe↔

	Ideal Fitting	Bad Fitting	Note
Bands	They are comfortably loose and do not slide on the front or the back.	They slide on the front or the back and are so tight that they cause discomfort.	The bands of a bra that fits well do leave red marks. And it is fine as long as they do not hurt. If the cups are too small, you might feel that the band is too tight as well. To see if the band fits well, you can put the bra on in any way, backward or upside down, as long as your breasts are not in the cups.
Cups	Your breasts fill the cups without overflowing.	Your breasts wrinkle, or they stick out on any side of the cups to create the so-called sideboobs.	Poor bra fitting could result from either a bad shape or the wrong size of the cups. To know which is the case with your bra, put on the same model of one size larger or smaller. If the problem was with the size, it should disappear or become less; otherwise, it is probably the shape issue.
Straps	They neither hurt nor slide off your shoulders.	They either hurt or slide off your shoulders.	Even if you choose a bra of the right size for you, its straps could still slide off if your shoulders are either sloping or narrow. If that is the case, you may want to use a racerback clip to solve the problem.
Gore	It rests comfortably on your breastbone.	It hangs loosely over your breastbone.	Sometimes, the gore does not tack well, even if the bra is good. Typically, it happens if the woman’s breasts are too close-set or in the case of specific skeletal abnormalities of the anterior thoracic wall (the so-called sunken chest). In the former case, you would gain from wearing U-plunge bras or any design that provides for lower cleavage. In the case of the sunken chest, though, you might have to learn to live with the gores that float.
Wires	They rest on the roots, where the breasts join the chest.	They are too loose and leave room on the outside, or they are too narrow and dig into the breasts, or they rest below the roots.

Bra Band Size Chart

The size steps (two inches and five cm, respectively) do not coincide, creating overlaps and offsets as a result. Besides, the larger the breast size, the more pronounced the differences become.

We need an instrument for accurate and precise conversion of the band sizes which takes these differences into account. The chart below will help women convert the band sizes into the French, American, or other regional equivalents.

Chart for Converting
the Bra Band Sizes (swipe ↔)
in	23	25	27	29	31	33	35	37	39	41	43	45	47	49	51	53	55	57	59	61	63	65	67
US⁺⁴/UK⁺⁴	28	30	32	34	36	38	40	42	44	46	48	50	52	54	56	58	60	62	64	66	68	70	72
US⁺⁰/UK⁺⁰	24	26	28	30	32	34	36	38	40	42	44	46	48	50	52	54	56	58	60	62	64	66	68

Internetional EU/JP/KO	60	65	70	75	80	85	90	95	100	105	110	115	120	125	130	135	140	145	150	155	160	165	170	175
FR/ES/BE	75	80	85	90	95	100	105	110	115	120	125	130	135	140	145	150	155	160	165	170	175	180	185	190
IT	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23
AU/NZ	6	8	10	12	14	16	18	20	22	24	26	28	30	32	34	36	38	40	42	44	46	48	50	52
cm	57.5	62.5	67.5	72.5	77.5	82.5	87.5	92.5	97.5	102.5	107.5	112.5	117.5	122.5	127.5	132.5	137.5	142.5	147.5	152.5	157.5	162.5	167.5	172.5

Bra Cup Size Chart

When it comes to the cup sizes, however, the differences between the two measurement systems, with all the overlaps and offsets, are even more important to consider than is the case with the band sizes.

That is especially so for the cups larger than Size D.

You will find plenty of conversion charts online, but most of them ignore this factor and, for that reason, become completely inappropriate for establishing the true size equivalent. That is why we have decided to include here a chart for a more accurate and precise comparison of the International, European, and other regional cup sizes.

We strongly recommend you to use the table below instead of the approximate and erroneous charts that you can find on the internet in abundance.

Chart for Converting
the Bra Cup Sizes (swipe ↔)
in	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	30
US⁺⁰	AA	A	B	C	D	DD/E	DDD/F	DDDD/G	H	I	J	K	L	M	N	O	P	Q	R
UK⁺⁰	AA	A	B	C	D	DD	E	F	FF	G	GG	H	HH	J	JJ	K	KK	L	LL	M	MM	N	NN	P	PP	Q	QQ
US⁺⁴				AA	A	B	C	D	DD/E	DDD/F	DDDD/G	H	I	J	K	L	M	N	O	P	Q	R
UK⁺⁴				AA	A	B	C	D	DD	E	F	FF	G	GG	H	HH	J	JJ	K	KK	L	LL	M	MM	N	NN	P	PP	Q	QQ

JP/KO					AA	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	P	Q	R	S	T	U	V	W	X	Y	Z

Internetional EU/FR/ES/BE/IT						AA	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	P	Q	R	S	T	U	V	W	X	Y	Z
AU/NZ						AA	A	B	C	D	DD	E	F	G	H	I	J	K	L	M	N	O	P	Q	R	S	T	U	V	W	X	Y	Z
cm	0	2	4	6	8	10	12	14	16	18	20	22	24	26	28	30	32	34	36	40	42	44	46	48	50	52	54	56	58	60	62	64	66	68	70	72	74	76

More information on bra sizes: 34A, 40DD/E, 38D, 38DD/E, 36DD/E, 32DD/E, 34DD/E, 38C, 32F, 38B, 32A, 32D, 30A, 36B, 36D, 32B, 36C, 34D, 34C, 34B

Conclusion

Measuring your bra size may be quite a tricky business indeed. And yet, you can do it well if you memorize the formulae and have a calculator and the charts and tables at hand. Otherwise, let our online calculator do the entire job for you, including the conversions across the measurement systems. All you do in this case is take accurate measurements, fill them in the corresponding fields, specify the measurement units, and press Enter.