Bra Size Calculator

Find your perfect bra size in US, UK, and EU sizing systems

Bra Size Calculator

Select your preferred measurement unit

Measure directly under your bust where your bra band sits

Measure around the fullest part of your bust

Select any issues with your current bra fit

How to Measure Your Bra Size

Getting accurate measurements is the first step to finding your perfect bra size. Here's how to measure yourself correctly:

Underbust Measurement

  1. Stand straight with your arms at your sides.
  2. Wrap the measuring tape directly under your bust, where your bra band would sit.
  3. The tape should be snug but not tight. You should be able to breathe comfortably.
  4. Make sure the tape is parallel to the ground all the way around.
  5. Round to the nearest whole number.

Bust Measurement

  1. Wear a non-padded bra that doesn't compress or enhance your natural shape.
  2. Stand straight with your arms at your sides.
  3. Wrap the measuring tape around the fullest part of your bust, typically at nipple level.
  4. The tape should be snug but not tight, and parallel to the ground all the way around.
  5. Round to the nearest whole number.

Calculating Your Size

Once you have your measurements, use our calculator above to determine your bra size. The calculator will:

  • Calculate your band size based on your underbust measurement.
  • Determine your cup size by finding the difference between your bust and underbust measurements.
  • Provide your size in US, UK, and EU sizing systems.
  • Adjust calculations based on any fit issues you're currently experiencing.

Bra Sizing Systems Explained

US Sizing System

The US sizing system uses a combination of numbers for band size and letters for cup size. Band sizes are typically even numbers (32, 34, 36, etc.), and cup sizes follow the sequence: AA, A, B, C, D, DD, DDD/F, G, H, I, J, K, L, etc.

UK Sizing System

The UK system uses the same band sizing as the US but has a different cup size progression after DD: A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, etc. Note that there is no I or II in the UK system.

EU Sizing System

European sizing uses band sizes in centimeters, typically in increments of 5 (65, 70, 75, etc.). Cup sizes follow the sequence: AA, A, B, C, D, E, F, G, H, I, J, K, etc. Some European brands may use different cup size progressions.

Sister Sizes

Sister sizes are bras with the same cup volume but different band and cup letter combinations. If you go up in band size, go down in cup size (e.g., 34C and 36B are sister sizes). This can be helpful if you're between sizes or if a particular brand runs small or large.

Common sister size examples:

  • 30D = 32C = 34B = 36A
  • 32DD = 34D = 36C = 38B
  • 34F = 36E = 38D = 40C

Common Fit Issues and Solutions

Band Rides Up in Back

Issue: Your band is too loose or has stretched out over time.

Solution: Try a smaller band size or use a tighter hook. Remember to go up a cup size if you go down a band size to maintain the same cup volume.

Straps Digging In or Slipping Off

Issue: Digging straps often mean your band isn't providing enough support. Slipping straps can indicate you need a smaller band or that the straps are too wide-set for your frame.

Solution: Ensure your band fits properly first. Then adjust strap length. Consider racerback or close-set straps if slipping is persistent.

Spillage or "Quadboob"

Issue: Your cups are too small, creating a double-breast effect where breast tissue spills over the top or sides of the cups.

Solution: Go up one or more cup sizes while keeping the same band size.

Gaping Cups

Issue: Your cups are too large or the style doesn't match your breast shape.

Solution: Try a smaller cup size or a different bra style that better suits your breast shape.

Center Gore Not Lying Flat

Issue: The center piece between the cups doesn't touch your sternum, often indicating cups that are too small.

Solution: Try a larger cup size or a style with a wider center gore.

Underwire Sitting on Breast Tissue

Issue: The underwire should encircle your breast tissue completely, not sit on it.

Solution: Try a larger cup size or a style with wider wires.

Types of Bras and Their Benefits

T-Shirt Bra

Smooth, seamless cups that provide a clean line under fitted clothing. Ideal for everyday wear and for those who prefer a natural, rounded shape.

Balconette Bra

Features wide-set straps and horizontal cups that lift from the bottom, creating a rounded, uplifted shape. Great for lower necklines and for adding fullness to the top of the bust.

Plunge Bra

Has a low center gore and angled cups that create cleavage. Perfect for low-cut tops and dresses.

Full-Coverage Bra

Covers the entire breast with higher cups, providing maximum support and minimizing spillage. Ideal for larger busts and those seeking comfort and support over cleavage.

Demi Bra

Covers about half to three-quarters of the breast with cups that are cut lower. Creates natural cleavage and works well under scoop necklines.

Push-Up Bra

Contains padding at the bottom and sides of the cups to lift and push breasts together, creating enhanced cleavage. Ideal for special occasions or for adding volume to smaller busts.

Sports Bra

Designed to minimize breast movement during physical activity. Comes in compression styles (flattening breasts against the chest) or encapsulation styles (supporting each breast individually).

Wireless Bra

Provides support without underwires, offering comfort for those with wire sensitivities or for lounging. Modern wireless bras can provide excellent support even for larger busts.

Frequently Asked Questions

How often should I measure my bra size?

It's recommended to measure your bra size every 6-12 months, as body changes from weight fluctuations, hormonal changes, pregnancy, menopause, or aging can affect your size. You should also remeasure if you notice discomfort or fit issues with your current bras.

Why does my bra size vary between brands?

Bra sizes can vary between brands due to different sizing standards, manufacturing processes, and target demographics. Some brands may run smaller or larger than others, and styles within the same brand can also fit differently. Always try on bras or check the specific brand's size chart before purchasing.

Should I measure with or without a bra on?

For the most accurate measurements, measure your underbust without a bra. For your bust measurement, wear a non-padded bra that doesn't compress or enhance your natural shape. If you don't have such a bra, measuring without one is acceptable, but stand straight and ensure the measuring tape is parallel to the ground.

How do I know if my bra fits correctly?

A well-fitting bra should have: a band that stays horizontal and feels snug but comfortable on the loosest hook; cups that fully contain your breasts without spillage or gaping; straps that stay up without digging in; and a center gore (the part between the cups) that lies flat against your sternum. You should be able to move comfortably without adjusting your bra.

What if I'm between sizes?

If you're between band sizes, try the smaller band with a larger cup or use an extender. If you're between cup sizes, try both sizes to see which fits better. Remember the sister size rule: if you go up in band size, go down in cup size (e.g., 34C to 36B), and vice versa.