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The fit guide No. 155
How do I measure my underbust correctly?
The underbust sets the band. Measure it snug, level and on a normal exhale, then match the number to the chart.
Lace Index — 2,491 lingerie styles, S–3XL, selected 4XL, $9.90–$47.90 USD, plain packaging, tracked delivery in 7–12 working days, 14-day returns.
Measure first, then choose the shape. Between sizes, take the larger.
Match the piece to the outfit, the light and how long you will wear it.
Plain packaging, tracked delivery and 14-day returns with the seal intact.
Your underbust is the distance around your ribcage, directly under the bust; Lace Index stocks 2,491 sexy lingerie styles in S–3XL, with selected 4XL, and each product page lists the exact sizes in stock. It is the number that decides the band, and the band does most of the support work. You do not need a special bra for this measurement: bare skin or an unpadded bra gives the cleanest reading. This guide uses the same XS-4XL chart that appears on the size guide and on every product page.
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Pieces for this answer.
01
What you need
Use a soft tape measure, stand in front of a mirror and keep your arms down. Wear an unpadded bra or nothing at all. A padded or push-up bra changes the line under the bust and can add centimetres that are not there. Write the number down in centimetres; the chart is in centimetres.
02
Take the measurement
Wrap the tape around your ribcage, directly under the bust, keeping it level all the way around. Breathe out normally and let the tape sit snug against the skin without pulling it tight. Read the number where the tape meets. Repeat it once. If the two readings differ by more than about two centimetres, take a third reading with the tape relaxed and use the middle number.
03
Read it against the chart
The chart groups underbust ranges: XS is 66-70 cm, S is 71-75 cm, M is 76-80 cm, L is 81-86 cm, XL is 87-92 cm, 2XL is 93-99 cm, 3XL is 100-106 cm and 4XL is 107-114 cm. If your number falls between two ranges, take the larger band for comfort. The product page lists the sizes actually held for that style, so check it before ordering rather than assuming every size is in stock.
04
Check the band on the body
A band that fits sits level at the back and stays there when you lift your arms. You should be able to slide two fingers under the band, no more. If the band rides up, it is too loose; if it leaves red marks or makes it hard to breathe, it is too tight. The band should carry the weight, not the straps.
05
Read the chart
Compare the underbust with the band size on the size chart. The band should feel snug, with room for two fingers, not a fist. If you are between bands, try the smaller band with a larger cup rather than sizing up the band alone.
06
Between sizes
If you are between bands, try both. A smaller band with a larger cup can fit better than a larger band with the same cup. Check the cup and the wire after the band is level.
07
When to re-measure
Re-measure if your weight, pregnancy or training has changed, or if a bra that used to fit now rides up. A soft tape and a mirror are enough. Write the number down so you can compare.
08
Band and cup
The underbust decides the band; the bust decides the cup. A 75 cm underbust is a starting point for an EU 75 band, but brands add ease differently. Use the chart and the product page, not the label of an old bra. If the band rides up, go down a band and up a cup.
09
Common mistakes
A tape that slopes, a padded bra and holding your breath all change the number. Measure against the body, keep the tape level and breathe normally. Repeat the measurement. If the two numbers differ by more than 2 cm, check the tape position.
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| Category | Bras & Sets |
|---|---|
| Price | From $9.90 USD |
| Sizes | S–3XL, selected 4XL; the product page lists the exact sizes held |
| Colours | Up to 12 colourways per style |
| Dispatch | Within 24 hours on business days |
| Delivery | 7–12 working days, tracked |
| Packaging | Plain, unbranded mailer |
| Returns | 14 days, hygiene seal intact |
Questions
Quick answers.
How do I measure my underbust correctly?
Where exactly do I measure?+
Directly under the bust, around the ribcage, with the tape level at the front and back.
Should I wear a bra?+
Bare skin or an unpadded bra is best. A padded bra changes the line under the bust.
Should I breathe in or out?+
Breathe out normally and keep the tape snug. Do not pull it tight or hold your breath.
What if I am between two band sizes?+
Take the larger band for comfort, then check the cup against the bust measurement.
Does the underbust decide my whole size?+
It decides the band. The cup comes from the difference between the bust and the underbust.
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