Ultimate Bra Size Calculator | Find Your Perfect Fit Instantly (US, UK, EU, FR)

👙 Ultimate Bra Size Calculator

Measure, convert, and find sister sizes. Supports inches & centimeters, US/UK/EU/FR/AU band conversions, and modern vs classic calculation methods.

Underbust (snug, right under bust)

Measure snug under the bust, exhale gently. Keep tape parallel to floor.

Bust (at fullest point)

Measure around the fullest part, tape comfortably taut but not tight.

Units

Method

Region (output style)

Tip: For best accuracy, measure while wearing a lightly lined bra.

Recommended Size

—

Band (US/UK)

—

Nearest even band

Cup

—

—

Sister Sizes

—

One up & one down

International Conversions

System	Size

How we calculated

Units	—
Method	—
Underbust (in)	—
Bust (in)	—
Base band (in)	—
Band (US/UK even)	—
Difference (bust - band)	—

Note: Cup is based on bust minus band in inches, rounded to nearest 0.5. Charts vary slightly by brand.

Fit Tips

• Band should be parallel to the floor and snug on the loosest hook when new.
• Cups should fully encase tissue with no gaping or overflow. Adjust straps after band fit.
• If band rides up, go down a band size (and up a cup for sister sizing).
• If cups wrinkle, go down a cup; if they spill, go up a cup.