Csiri Intimates Size Calculator

Use your measurements in cm (or inches) OR type what’s written on your tag (UK / EU / US / FR).

Mode

If you already have a bra that fits, “By size code” is more accurate.

Unit

Underbust (snug)

Tape around ribs under bust. Snug, not painful.

Bust (fullest)

Tape around fullest part. Keep it level.

Your bra size results

Recommended (UK)

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EU / CN

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Chinese fit alternate

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Bralette alpha size

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Sister sizes

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Note: brands vary. EU / CN shows the direct conversion. If a Chinese-made bra cup feels small, try the Chinese fit alternate.

Csiri Bra Fit Guide

Use this guide to understand how our bra calculator works, how to measure correctly, and what to do if a bra feels off after you try it on.

How to measure your bra correctly

Underbust: wrap the tape directly under the breasts, around the ribcage. Keep it level all around and snug, not painful.
Bust: measure around the fullest part of the bust. Keep the tape level and not overly tight.
Stand naturally: don’t puff your chest too much or pull the tape too tightly.
Use a non-padded bra if possible: heavily padded bras can distort the fullest-bust measurement.
If between numbers: use the calculator result as your starting point, then confirm by fit.

How our calculator works

Your underbust helps determine your band size.
The difference between your bust and your band helps determine your cup size.
We then convert that size into UK, US, EU / CN, and FR.
For Chinese-made bras, we also show a fit alternate because some imported bras run small in the cup.

Example:
If your result is UK 34D, your direct EU / CN size is 75D.
If the cup feels small in a Chinese-made bra, try 75E.

Quick bra measurement guide

Step	What to measure	How to do it	Important tip
1	Underbust	Measure snugly around the ribcage directly under the bust.	Keep the tape straight and level all around.
2	Full bust	Measure around the fullest part of the bust.	Do not squeeze the bust flat with the tape.
3	Calculator result	The calculator uses the difference between bust and band to estimate your cup.	This is your starting size, not always the final fit.
4	Try-on check	Check band, cups, straps, and center gore after wearing the bra.	Different brands and styles can fit differently.

Bra size conversion chart

UK	US	EU / CN	FR	Notes
30A	30A	65A	80A	Small band, shallow cup
32B	32B	70B	85B	Common starter reference
34C	34C	75C	90C	Balanced mid-size reference
34D	34D	75D	90D	If Chinese cups run small, try 75E
36D	36D	80D	95D	Common fuller band reference
36DD	36DD	80E	95E	UK double-letter cup system
38C	38C	85C	100C	Wider band, moderate cup
38D	38D	85D	100D	Often seen in everyday bras
40C	40C	90C	105C	Fuller band size range
40D	40D	90D	105D	Check support from band first

This chart is a quick guide. Your calculator result is more accurate than choosing by chart alone.

Signs your bra fits well

The band sits level around your body and does most of the support work.
The center gore lies flat against the chest.
Your breasts sit inside the cups without spilling over the top or sides.
The cups do not wrinkle or gape excessively.
The straps feel secure without carrying all the weight.

Signs something is off

Overflow / spillage: the cup is likely too small.
Gaping: the cup may be too large or the style may not suit the breast shape.
Band riding up at the back: the band may be too loose.
Underwire sitting on breast tissue: the cup is likely too small or the bra shape is wrong.
Straps digging in: the band may not be giving enough support.

What to do if the calculator size does not feel right

Band feels tight → try sister sizing Cups feel small → go one cup up Chinese cup feels small → keep band, go one cup up Band rides up → go down a band

Example:
If the calculator gives UK 34D and the band feels right but the cup feels tight, try:
Chinese / EU alternative: 75E

Tip: if you already own a bra that fits you really well, using that label size in the calculator can be just as useful as fresh measurements.

Mode

Most tags you’ll see: S/M/L or UK 8/10/12 (sometimes “size 10”).

Unit

Waist

Natural waistline.

Hips

Widest part of hips.

Your panty size results

Recommended (Alpha)

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UK size

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EU size

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US size

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Comfort option

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Waist / Hips range

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These are approximate ranges. If between sizes, choose the comfort option.

Csiri Panty Fit Guide

Use this guide to understand how our panty calculator works, how to measure correctly, and how to choose the best size for comfort.

How to measure for panties correctly

Waist: measure around your natural waistline.
Hips: measure around the fullest part of your hips and bum.
Keep the tape level: make sure it stays straight all around the body.
Do not pull too tight: the tape should rest on the body, not dig in.
Hips matter most: for panties, hip measurement is usually the most important size guide.

How our panty calculator works

We use your waist and hips to find the closest size range.
Your result is shown in Alpha size like S, M, L, XL because that is easier for most customers.
We also show the matching UK, EU, and US size equivalents.
If you are between sizes, the calculator also shows a comfort option.

Example:
If your measurements fall into the XL range, your result may show:
XL / UK 16 / EU 44
Comfort option: UK 18

Quick panty measurement guide

Step	What to measure	How to do it	Important tip
1	Waist	Measure around your natural waistline.	This helps confirm fit, but it is not the main measurement for panties.
2	Hips	Measure around the fullest part of your hips and bum.	This is usually the most important measurement for panty sizing.
3	Calculator result	The calculator matches your numbers to the closest waist and hip range.	The result is your best starting size.
4	Comfort check	If you are between sizes or prefer less pressure, use the comfort option.	For panties, sizing up is usually better than sizing down.

Panty size chart

Alpha	UK	EU	US	Waist (cm)	Hips (cm)
XS	UK 4–6	EU 32–34	US 1–2	58–66	84–92
S	UK 8	EU 36	US 4	66–71	91–97
M	UK 10–12	EU 38–40	US 6–8	71–81	97–107
L	UK 14	EU 42	US 10	81–86	107–112
XL	UK 16–18	EU 44–46	US 12–14	86–96	112–122
XXL	UK 20	EU 48	US 16	96–101	122–127
3XL	UK 22	EU 50	US 18	101–106	127–132
4XL	UK 24	EU 52	US 20	106–111	132–137
5XL	UK 26	EU 54	US 22	111–116	137–142

Signs your panty size is right

The waistband sits comfortably without cutting in too hard.
The fabric lies smoothly without excessive pulling.
The leg openings feel secure but not painfully tight.
You can move, sit, and walk comfortably.
The fit feels supportive without making you constantly adjust.

Signs you may need a bigger size

The waistband digs in too much.
The leg openings pinch or leave strong marks.
The fabric stretches too hard across the hips.
You notice rolling, bunching, or constant discomfort.
You are between two sizes and the smaller one feels too exact.

Best sizing advice for panties

Hips matter most Use waist as support check Between sizes? Go up Comfort matters more than squeezing in

Tip:
If your result lands between two sizes, choose the larger one for comfort, especially for everyday wear, uniforms, bodycon outfits, or long work days.

For panties, measurements are usually more reliable than label letters alone because S, M, L, and XL can vary from brand to brand.