Bra Size Calculator UK | Find Your Fit in 2 Minutes | MissFine

Bra Size Calculator UK — Find Your Perfect Fit | MissFine
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Bra Size Calculator UK

Find your perfect bra size in 2 minutes. Free calculator with UK, US, EU, Australian and Canadian conversions, sister sizes, and personalised fit advice. No measuring tape required for the fit check path.

What Bra Size Am I?

Answer a few quick questions and we'll calculate your ideal bra size with international conversions, sister sizes, and personalised fit advice.

🔒 Private & Secure⏱ Takes 2 minutes🌐 All sizes worldwide

Choose your experience

Select one to get started

Find My Size
Measure and get your exact size with personalised recommendations
Check My Fit
Tell us how your bra feels — we'll work out the right size for you
Find My Style
Discover which bra styles suit your lifestyle best
Measurements
1

Take Your Measurements

You'll need a soft measuring tape. Stand naturally, breathe normally, bra off.

📏 How to measure:
1. Upper bust — Across the fullest part of your chest.
2. Under bust — Snugly around your ribcage below the breast.

No measuring tape? Use a piece of string and measure it flat against a ruler.

cm
cm
Pro tip: Keep the tape parallel to the floor and firm — not tight. Measure twice for accuracy.
Step 1 of 5
1

What size are you wearing now?

We'll use this as our starting point.

Quick tip: Check the label inside your bra — size is on the back hook or side seam.
≈ UK size: —
Step 2 of 5
2

How does the band feel?

The band does 80% of the support work.

✓
Snug and comfortable all dayStays level, two fingers fit underneath
✓
↑
Rides up my backThe back rises higher than the front
✓
!
Too tightHard to breathe or feels constricting
✓
~
Digs in and leaves marksRed marks or indentations after wearing
✓
Step 3 of 5
3

How do the straps behave?

✓
Stay in place all dayNo sliding, no digging
✓
↓
Fall off my shouldersEven when tightened they slip
✓
!
Dig in even when loosenedPainful grooves in my shoulders
✓
~
Leave painful red marksDeep indentations by end of day
✓
Step 4 of 5
4

How do the cups fit?

✓
Smooth and fully containingNo gaps, no overflow, flat edges
✓
↑
I spill over the top or sidesBreast tissue escaping the cup
✓
○
Gaping or empty spaceCup doesn't make full contact
✓
≡
Double-bust effectCup edge cuts into breast tissue
✓
Step 5 of 5
5

What about the front panel?

The centre gore — the strip between the cups.

✓
Lies flat against my sternumSits flush with no gap or pressure
✓
↑
Lifts away from my chestFloats or gaps away from my body
✓
!
Digs into my breast tissuePainful where it presses in
✓
—
I wear wire-free brasNo centre gore to assess
✓
Step 1 of 5
1

When do you most need a bra?

Select all that apply.

☕
Everyday wear
✓
💼
Work & office
✓
🏃
Exercise & sport
✓
🌹
Evenings out
✓
🌙
Sleep & lounge
✓
✨
Special occasions
✓
Step 2 of 5
2

What's your style aesthetic?

🤍
Clean & minimalInvisible, seamless, no fuss
✓
🌸
Feminine & prettyLace, delicate details, soft colours
✓
⚡
Sporty & functionalPerformance over form
✓
🌹
Sensual & confidentLingerie that makes me feel stunning
✓
Step 3 of 5
3

How do you feel about underwire?

💪
I love itGives me the shape and lift I want
✓
🙅
I avoid itComfort always comes first
✓
🤷
Depends on the occasionI wear both
✓
Step 4 of 5
4

What coverage do you prefer?

🛡
Full coverageCompletely contained, maximum modesty
✓
👌
MediumGood support without being restrictive
✓
💋
Low-cut plungeI like a flattering neckline
✓
Step 5 of 5
5

What matters most in a bra?

👻
Invisible under clothes
✓
😌
All-day comfort
✓
✨
Flattering shape
✓
💪
Maximum support
✓
Your MissFine Size
—
UK · Primary Size
Shop My Size on MissFine →
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🇺🇸 US—
🇨🇦 CA—
🇪🇺 EU—
🇫🇷 FR/ES—
🇦🇺 AU/NZ—
Shop Your Size on MissFine
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Free UK delivery · 30-day returns · Sizes 32A to 48F

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What to Change & Why

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Your Style Profile
—
—
Your Perfect Match
Also Worth Trying

Sizes 32A to 48F · Free UK delivery · 30-day returns

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Why the right fit changes everything

80%of women wear the wrong bra size without realising it
6+size changes the average woman goes through in her lifetime
2 minis all it takes to find your perfect fit with our calculator

A well-fitting bra improves posture, reduces back and shoulder pain, and changes how you feel wearing clothes.

🌐

International Sizing

UK, US, CA, EU/FR, and AU/NZ systems.

↔

Sister Sizes

Equivalent sizes across band widths.

🔍

Fit Diagnostics

Diagnose and fix common fit issues.

✨

Style Matching

Personalised style recommendations.

Not sure where to start?

Pick any path above. Our calculator guides you through every step.

How to measure your bra size at home

Follow these easy steps using a soft measuring tape. For the most accurate result, wear a non-padded bra or nothing at all.

Band measurement (band size): Wrap the measuring tape snugly around your torso at the level of your rib cage, directly below your breast tissue where your ribs meet your breasts, parallel to the floor. Make sure the tape is not slipping down at the back. Round to the nearest even number. That is your band size. If you measure 31 inches, your band is 32. If you measure 33 inches, your band is 34.

Bust size (cup size): Wrap the tape loosely around the fullest part of your bust, straight and parallel to the floor. Do not pull tight. The inch difference between your bust size and band measurement gives your cup size: 1 inch = A, 2 = B, 3 = C, 4 = D, 5 = DD, 6 = E, 7 = F, 8 = FF. For example, a 32-inch band and a 35-inch bust gives a 32C. MissFine uses UK sizing throughout. Canadian sizing is identical to UK.

Do not add inches to your underbust. Adding 4 or 5 inches is an outdated method from when bra fabrics had almost no stretch. Your actual underbust measurement is your band size.

Once you have put on your bra, lean forward and use your hands to gently scoop all breast tissue fully into the cups before standing upright. This is the Swoop and Scoop method and ensures correct positioning, especially for underwired styles. It is worth checking your measurements every 12 to 18 months, as weight, hormonal changes, and ageing all affect bra size over time.

Shop by style once you know your size: Browse our full range of bras, including T-shirt bras, sports bras, front closure bras, balconette bras, and plus size bras. Not sure which style? Read our guide on what is a balconette bra or explore lace bras for something more feminine.

Bra fitting guide: styles for your breast shape

Every body is different. Knowing your breast shape helps you choose the most flattering and comfortable bra style. Here are the most common shapes and which bras work best for each.

Round
Equally full on top and bottom with a defined rounded profile. Most bra styles work beautifully. T-shirt bras and balconettes are especially flattering. Avoid heavy padding — you already have natural shape.
Teardrop (Full Below)
Less fullness on top, fuller at the bottom. The most common breast shape. Moulded T-shirt bras and full-cup styles give the best lift and shape. Push-up styles add upper fullness if desired.
East-West
Nipples point outward with a wider gap in the centre. A plunge or front-closure bra draws the breasts toward the centre for a flattering cleavage line. Avoid wide-set straps which can emphasise the outward angle.
Side-Set (Wide)
Breast tissue sits toward the underarm with a wider gap between them. Look for bras with side support panels or side-sling construction. Full-cup styles with strong side wings collect tissue and centre it beautifully.
Athletic (Wider, Flatter)
Wider at the base with less projection. Muscular chest wall. Bralettes, triangle bras, and lightly padded styles add gentle shape. Underwire can feel uncomfortable on a muscular chest — try wire-free options first.
Bell (Narrow, Full Below)
Slimmer at the top, heavier at the bottom with a bell-like profile. Full-cup bras with firm underwire offer the best support for the lower fullness. Look for styles with a three-part cup construction for natural shaping.

Six signs your bra doesn't fit

The band rides up at the back
The band should sit snug on your ribs and stay level across your torso. If it rides up, the bra is too loose. A riding band causes the breasts to drop, leading to spillage and back aches. The band does 80% of the support work. If it is not level, it is not working.
The straps dig in or slide off
Straps should not be the main source of support. If they are digging into your shoulders, your underband is too loose and the straps are compensating. If the straps slide or drop, the band is likely too big. Red marks on your shoulders that last more than an hour mean you need to drop a band size.
The cups gap or overflow
Gaping means the cup is too big or the wrong shape for your breast shape. If breast tissue is spilling out at the top or sides, the cup is too small. Both are fit problems, not body problems.
The underwire sits on breast tissue
The underwires should sit flat against your chest wall with no breast tissue between the underwire and your ribs. The centre front should sit flat against the chest bone. If the centre front lifts away, the cup is too small. This applies to everyday bras and sports bras.
There is a groove in your shoulder
Deep red marks or grooves that last after removing the bra mean straps are carrying weight the band should be carrying. Drop a band size.
You adjust it more than twice a day
A well-fitting bra stays put. Constantly repositioning the cups, pulling the band down, or pushing the straps up is a sign your current bra size is not right. That is worth checking.

UK bra size chart & size converter

UK / CA US EU FR/ES AU/NZ
32A 32A 70A 85A 10A
34B 34B 75B 90B 12B
36C 36C 80C 95C 14C
36D 36D 80D 95D 14D
36DD 36DD 80E 95E 14DD
36E 36DDD/F 80F 95F 14E
36F 36G 80G 95G 14F
38FF 38H 85H 100H 16FF
38G 38I 85I 100I 16G
40GG 40J 90J 105J 18GG
40H 40K 90K 105K 18H

UK cup sizing runs: A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ. Canadian sizing is identical to UK sizing. Australian and New Zealand sizing uses the same cup letters as UK but different band numbers (UK 32 = AU 10, UK 34 = AU 12 and so on). The main difference between US and UK sizing is in the cups above D: a US DD equals a UK DD, but from there US uses DDD where UK uses E. Bra sizes can vary between brands, so always use your measurements rather than a label from a previous purchase. If you are trying bras in a fitting room, test your calculated size alongside one cup size up and one down.

Understanding bra sister sizes

Sister sizes are bra sizes that share the same cup volume but have different band sizes. They are useful when your usual band size feels slightly too tight or too loose, or when a specific style only comes in limited sizes.

How sister sizes work: If you go down one band size, go up one cup size to keep the same cup volume. If you go up one band size, go down one cup size. For example, 34C, 32D and 36B are all sister sizes — the cup holds the same amount, but the band tightness differs.

Tighter Band (↓1 band, ↑1 cup) Your Size Looser Band (↑1 band, ↓1 cup)
30D 32C 34B
32DD 34D 36C
34E 36DD 38D
36FF 38F 40E
38GG 40G 42FF

Our calculator shows your sister sizes automatically. When shopping, try your main size first, then a sister size if the band or cup does not feel right. A sister size is not a replacement for the correct size — it is a nearby alternative when you need a slight adjustment.

Frequently asked questions

What bra size am I?
Enter your underbust and bust measurements into the bra size calculator above. You will get your UK size, US equivalent, Canadian, EU, FR/ES and AU/NZ conversions, and your sister size options.
How do I measure my bra size at home?
Use a measuring tape and two measurements: underbust for band size and bust size for cup size. Wear a non-padded bra or nothing. Do not add inches to your underbust. That is an outdated method. Each inch of difference corresponds to one cup size: 1 inch = A, 2 = B, 3 = C, and so on.
What is the difference between UK and US bra sizes?
UK and US band sizes are identical. Both systems use DD. Above DD, the letters diverge: UK uses E where US uses DDD, UK uses F where US uses G, and UK uses FF where US uses H. The UK system uses double letters (DD, FF, GG, HH) for larger cup sizes. Canadian sizing is identical to UK, not US.
What is a sister size in bras?
Sister sizes share the same cup volume but have different band sizes. A 36C, 34D and 38B are all sister sizes with the same cup volume. If you drop a band size, go up a cup size to maintain the same cup volume. If you go up a band, drop a cup size.
How does MissFine label cup sizes?
MissFine uses UK sizing throughout. The cup sequence is A, B, C, D, DD, E, F, FF, G, GG, H. Canadian sizing is identical to UK so no conversion is needed. If you are used to US sizing, DD is the same, but US DDD equals UK E and US G equals UK F.
What sizes does MissFine stock?
MissFine stocks bras from 32A to 48F and 44G including 40 front-opening styles and sports bras across the full size range. All sizes use UK cup labelling: A, B, C, D, DD, E, F, FF, G.
Why should I not add 4 inches to my underbust measurement?
The old plus-4-inch method was developed when bra fabrics had almost no stretch. Today's bras use elastic fabrics. Adding 4 inches gives a band that is too large to provide proper support. Your actual underbust measurement, rounded to the nearest even number, is your band size.
How do I know if my bra fits correctly?
A bra that fits should feel like a second skin — supportive but barely noticeable. The band sits level on your ribs. Two fingers slide flat underneath. Straps stay in place without digging in. Cups fully contain your breast tissue. The underwires sit flat against your chest wall. The centre front sits flat against your sternum. Always fasten on the loosest hooks when the bra is new.
What is the difference between cup size and band size?
The band size (the number) is the circumference of your ribcage below your bust. The cup size (the letter) is the difference between your bust and underbust measurements. It is not an absolute size. A 32D and a 38D are completely different sizes.
How often should I remeasure my bra size?
Accurate measurements change over time due to weight fluctuations, hormonal changes, and ageing. Remeasure every 12 to 18 months as a routine check, and after any significant weight change, pregnancy, or breastfeeding period. If your bra suddenly feels different (band riding up, cups gaping), remeasure before buying new bras.
What is the Swoop and Scoop method?
After putting on your bra, lean forward and scoop all breast tissue fully into the cups before standing upright. This positions your breasts correctly and gives you the full support the bra is designed to provide, especially for underwired styles and sports bras.
How does Australian bra sizing work?
Australian (and New Zealand) bra sizing uses different band numbers from UK sizing. A UK 32 is an AU 10, UK 34 is AU 12, UK 36 is AU 14, and so on — each UK band size up adds 2 to the AU number. Cup letters are the same as UK. Our calculator converts automatically.
Is Canadian bra sizing the same as UK?
Canadian bra sizing is identical to UK sizing, not US. Band sizes and cup letters are the same: A, B, C, D, DD, E, F, FF, G, GG, H. If you know your UK size, that is also your Canadian size. No conversion is needed.

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