Bra Size Calculator UK 2025 — Find Your UK Bra Size Instantly
🇬🇧 UK Sizing Standard
UK Bra Size Calculator Find Your Perfect British Fit
Enter your underbust and bust measurements below — in inches or centimetres — and get your exact UK bra size instantly, including sister sizes and personalised fit advice.
2measurements needed
12+UK cup sizes covered
100%free to use
1
Underbust (band)Snugly under bust, tape level all around
2
Fullest bustLoosely across fullest point, don't compress
3
CalculateEnter both numbers and press the button
UK Bra Size Calculator
Measure snugly under your bust. Round odd numbers up by 1.
Measure loosely around the fullest part of your chest.
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Your UK bra size
🇬🇧
UK band size
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UK cup size
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Difference
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UK cup scale — your size highlighted
Equiv. sizes
UK sister sizes — same cup volume, different band
UK fit tip
UK Bra Size Chart
Complete UK cup sizes by underbust-to-bust difference, with international conversions
UK cup sizes by underbust-to-bust difference in inches
Difference (in)
UK Cup
Example UK Size
US Equivalent
EU Equivalent
0–½"
AA
34AA
AA
AA
1"
A
34A
A
A
2"
B
34B
B
B
3"
C
34C
C
C
4"
D
34D
D
D
5"
DD
34DD
DD
E
6"
E
34E
DDD / F
F
7"
F
34F
G
G
8"
FF
34FF
H
H
9"
G
34G
I
I
10"
GG
34GG
J
J
11"
H
34H
K
K
12"
HH
34HH
L
L
UK band sizes by underbust measurement
Underbust (in)
UK Band
Underbust (cm)
EU Band (cm)
22–23"
24
56–59 cm
55
24–25"
26
60–63 cm
60
26–27"
28
64–68 cm
65
28–29"
30
69–73 cm
70
30–31"
32
74–79 cm
75
32–33"
34
80–84 cm
80
34–35"
36
85–89 cm
85
36–37"
38
90–94 cm
90
38–39"
40
95–99 cm
95
40–41"
42
100–104 cm
100
42–43"
44
105–109 cm
105
44–45"
46
110–114 cm
110
UK to EU bra size conversion chart
UK Size
EU Band
EU Full Size
Notes
28D
60
60D
Same cup letter
30D
65
65D
Same cup letter
32D
70
70D
Same cup letter
34D
75
75D
Same cup letter
36D
80
80D
Same cup letter
34DD
75
75E
UK DD = EU E
34E
75
75F
UK E = EU F
34F
75
75G
UK F = EU G
34FF
75
75H
UK FF = EU H
34G
75
75I
UK G = EU I
UK to US bra size conversion chart
UK Size
US Equivalent
Cup difference
Notes
34A
34A
None
Identical up to D
34B
34B
None
Identical up to D
34C
34C
None
Identical up to D
34D
34D
None
Identical up to D
34DD
34DD
None
Both use DD
34E
34DDD / 34F
+1 UK letter
UK E = US DDD
34F
34G
+1 UK letter
UK F = US G
34FF
34H
+1 UK letter
UK FF = US H
34G
34I
+1 UK letter
UK G = US I
34GG
34J
+1 UK letter
UK GG = US J
Definition
A UK bra size calculator converts your underbust and bust measurements into a British-standard bra size, expressed as an even number (band) and a letter or double-letter (cup). UK cup sizing uses a unique progression — AA, A, B, C, D, DD, E, F, FF, G, GG, H, HH — which differs from US sizing after the DD cup.
How UK Bra Sizing Works
UK bra sizing is based on two measurements: the underbust (for the band) and the fullest bust (for the cup). The band size is the underbust measurement rounded up to the nearest even number — so a 31-inch underbust gives a UK 32 band, and a 33-inch gives a UK 34 band.
The cup size is determined by subtracting the band measurement from the bust measurement. Each inch of difference corresponds to one UK cup size, using the British progression of letters. This is where UK sizing diverges from US sizing — particularly at and above a DD cup.
"UK bra sizing after DD cup uses E, F, FF, G, GG, H — not DDD or G as in US sizing. Always check the brand's country when buying online."
UK cup letter progression explained
1 inch difference = A cup
2 inches = B cup
3 inches = C cup
4 inches = D cup
5 inches = DD cup (same as US DD)
6 inches = E cup (US calls this DDD or F)
7 inches = F cup (US calls this G)
8 inches = FF cup (US calls this H)
9 inches = G cup (US calls this I)
UK vs US vs EU Bra Sizing — Key Differences
The most common source of confusion when shopping across borders is the divergence of cup letters after DD. UK and EU sizing both use E for a 6-inch difference; US sizing uses DDD or F. UK uses FF for an 8-inch difference; most other systems use H. Always check the conversion table above when buying from non-UK brands.
Band sizes are also calculated slightly differently. In EU sizing, bands are expressed in centimetres (60, 65, 70, 75, 80...) rather than inches. A UK band 34 corresponds to EU band 75. The converter built into the result panel above handles this automatically.
Sister Sizes in UK Bra Sizing
Sister sizes work identically in UK sizing as in any other system: going up one band size and down one cup letter preserves the same cup volume. This is useful across UK retailers because brand sizing varies — even between Marks & Spencer, ASOS, and Bravissimo, a 34D may fit differently.
If a UK 34D fits in cup volume but the band is slightly loose, try a 32E. If the band is tight, try a 36C. All three contain the same breast volume in the UK system.
Common UK Bra Fitting Mistakes
Using the old "add 4 inches" rule: This outdated method was developed for rigid vintage bras and consistently leads to too-large a band. Measure your actual underbust.
Treating UK and US labels as identical: After DD cup, UK and US cup letters diverge significantly. A UK 34F is not the same as a US 34F.
Buying by label size across UK brands: Sizing varies between Marks & Spencer, Next, Debenhams, Bravissimo, and ASOS. Use your measurements, not the label.
Ignoring the band: The band provides 80% of a bra's support. If the band rides up at the back, it is too large — not too tight.
Never remeasuring: UK women's bodies change with weight, age, pregnancy, and hormonal cycles. Remeasure every 1–2 years.
Frequently Asked Questions
Common questions about UK bra sizing, measurement, and fit
Women's Bra Size Calculator (Inches & cm)
how to calculate UK bra size manually step by step
Step 1: Measure Your Band Size (Underbust)
Start with a snug measurement around your ribcage. This step is essential in a UK women’s bra size calculator in inches & cm because the band provides most of the support. Use a soft tape and ensure it sits straight across your back.
Long-tail keyword used: how to measure band size UK bra at home
📐 Step 2: Measure Your Bust Size
Wrap the tape around the fullest part of your chest without compressing it. This ensures your accurate bust measurement for UK bra size calculation. Keep the tape level and relaxed for natural positioning.
Long-tail keyword used: accurate bust measurement for bra size UK system
🔢 Step 3: Calculate the Cup Size Difference
Subtract your band size from your bust size. This difference determines your cup. In a UK bra size calculator inches to cm conversion, each inch difference equals a cup size (A, B, C, etc.).
Difference
UK Cup
1 inch
A
2 inches
B
3 inches
C
4 inches
D
5 inches
DD
Long-tail keyword used: UK bra cup size difference chart inches and cm
🔄 Step 4: Convert Inches to CM (If Needed)
If you measured in centimeters, divide by 2.54 to convert to inches. This helps when using a UK women’s bra size calculator in cm and inches online.
Example: 89 cm ÷ 2.54 = 35 inches
👙 Step 5: Combine Band + Cup
Your final size combines both measurements. For example:
Band: 30 inches
Difference: 5 inches
Result: 30DD UK bra size
Women's Bra Size Calculator UK
Finding the right bra size in the UK can be challenging. Our women's bra size calculator UK helps you discover your accurate size using simple underbust and bust measurements. This tool supports all major UK brands like Marks & Spencer, Triumph, Panache, and Chantelle, and allows you to enter measurements in centimetres or inches.
Your UK Bra Size:
–
Unit
Underbust
Bust
Difference
Band
Cup
UK Size
Enter measurements above to calculate your bra size.
How to Measure for a UK Bra
Place a soft tape measure under your bust to find your band measurement.
Measure across the fullest part of your bust to determine the cup size.
Use centimetres for precision or inches if preferred; the calculator converts automatically.
Check against brands like Triumph, Panache, and Marks & Spencer for accurate fit.
Why Use This Calculator?
Eliminates guesswork when buying bras online or in-store
Supports all major UK brands and sizes
Interactive, user-friendly, and mobile-responsive
Displays your bra size along with a detailed measurement table
How to Measure Your Bra Size
Select Your Unit: Choose between cm or inches. The calculator converts automatically.
Measure Your Underbust: Wrap a soft tape measure under your bust. Record the measurement; this is your band size.
Measure Your Bust: Measure around the fullest part of your bust. This determines your cup size.
Enter Your Measurements: Input the underbust and bust measurements into the calculator fields above.
Click Calculate: The calculator will show your UK bra size and update the detailed table with your measurements and corresponding band and cup sizes.
Reference the UK Bra Size Chart: Confirm your size against popular UK brands for the best fit.
Final Tips for a Perfect Fit
Even with accurate measurements, bra sizes can slightly differ between brands. Use the calculated size as a starting point and always try on bras when possible. Adjust for comfort and support rather than relying solely on numbers.
