How To Measure Your Bra Size
Last updated: April 18, 2025
Finding your perfect bra size is simple with our easy-to-follow guide. Learn how to measure yourself accurately using just a soft measuring tape.
Preparation
Before you begin measuring, gather these essentials for accurate results:
- Measuring Tape: Use a soft, flexible measuring tape
- Appropriate Attire: Wear a non-padded bra or a snug tank top
- Good Lighting: Find a well-lit, private space with a mirror
- Notepad: Keep a notepad handy to write down your measurements
Step 1: Measure Your Band Size
Wrap the measuring tape snugly around your ribcage, directly under your bust. Ensure the tape is level and straight across your body.
Tip: If the measurement falls between two numbers, round to the nearest whole number.
Step 2: Measure Your Bust Size
Wrap the measuring tape around the fullest part of your bust. Make sure the tape is parallel to the ground and not too tight or too loose.
Tip: Round the measurement to the nearest whole number if needed.
For more accuracy in our Advanced Measurement mode, take three bust measurements:
- Standing bust measurement
- Leaning bust measurement (bending forward at 90 degrees)
- Lying bust measurement (lying flat on your back)
Step 3: Calculate Your Bra Size
Subtract your band size (Step 1) from your bust size (Step 2) to find the difference. Each inch of difference corresponds to a specific cup size:
- 1 inch difference = A cup
- 2 inches difference = B cup
- 3 inches difference = C cup
- 4 inches difference = D cup
- And so on...
For example, if your band size is 34 inches and your bust size is 36 inches, the difference is 2 inches, making your bra size 34B.
Understanding International Sizing
Different countries use different sizing systems. Our calculator automatically converts your measurements to the following systems:
Cup Size Chart
| Diff (cm) | UK | US | EU | FR | AU | JP |
|---|---|---|---|---|---|---|
| <1 cm | AA | AA | AA | AA | AA | - |
| 1 (2.5) | A | A | A | A | A | A |
| 2 (5.1) | B | B | B | B | B | B |
| 3 (7.6) | C | C | C | C | C | C |
| 4 (10.2) | D | D | D | D | D | D |
| 5 (12.7) | DD | DD/E | E | E | DD | E |
| 6 (15.2) | E | DDD/F | F | F | E | F |
| 7 (17.8) | F | G | G | G | F | G |
| 8 (20.3) | FF | H | H | H | G | H |
| 9 (22.9) | G | I | I | I | H | I |
| 10 (25.4) | GG | J | J | J | I | J |
| 11 (27.9) | H | K | K | K | J | K |
| 12 (30.5) | HH | L | L | L | K | L |
| 13 (33.0) | J | M | M | M | L | M |
| 14 (35.6) | JJ | N | N | N | M | N |
Using Our Calculator
Our calculator makes finding your size quick and easy:
- Enter your band measurement in the "Band Size" field
- Enter your bust measurement in the "Bust Size" field
- Select your country/region and preferred unit (inches or centimeters)
- Click "Calculate My Size"
For more precise results, try our Advanced Measurement option, where you can enter standing, leaning, and lying bust measurements for a more accurate calculation.
Try the Reverse Calculator
Already know your bra size but want to understand your measurements? Use our Reverse Calculator to convert your current bra size into the equivalent measurements.
Finding the Right Fit
Remember that our calculator provides a starting point. Factors like body shape, breast shape, and brand variations can affect the perfect fit. Always try on bras when possible and look for these signs of a good fit:
- The band should be snug but comfortable, parallel to the ground
- Cups should fully contain your breast tissue without spillage or gaps
- The center gore (between the cups) should lie flat against your sternum
- Straps should stay in place without digging into your shoulders