How To Measure Bra Size
Last updated: April 21, 2025
This guide will walk you through how to calculate your bra size using a bra size calculator in inches or centimeters.
Follow these steps to learn how to measure your bra size at home using just a soft measuring tape
Preparation for Bra Measurement
Before determining your bra size, gather the following items for accurate results.
A soft measuring tape is a must, but having a mirror, a notepad to jot down measurements, and wearing a non-padded bra or snug tank top can make the process easier and more precise.
Measuring Tape
Use a soft, flexible measuring tape.
Measurement Unit
Choose inches or centimeters.
What to Wear
Wear a non-padded bra or no bra.
Mirror (Optional)
To your measuring tape is level.
Things to Consider Before Determining Bra Size
- What to Wear: For the best results, wear a non-padded bra or a snug-fitting tank top. Avoid bulky or padded clothing.
- When to Measure: Measure when your breasts are their most natural state, ideally a few days after your menstrual cycle ends to account for any size fluctuation.
- Where to Measure: Find a comfortable, private space with a mirror. This helps ensure the measuring tape is level and correctly positioned.
- Setting Up the Environment: Ensure the room is well-lit and you have a flat surface to stand on. Keep a notepad handy to jot down your measurements.
Step 1: Measure Your Band Size
To calculate bra size, wrap the measuring tape snugly around your ribcage, directly under your bust. Make sure the tape is level and straight across your body.
Tip: If the measurement falls between two numbers, round it to the nearest whole number.
Step 2: Measure Your Bust Size
Wrap the measuring tape around the fullest part of your bust. Ensure the tape is parallel to the ground and is not too tight or too loose.
Tip: Round the measurement to the nearest whole number if it falls between two values.
Step 3: Calculate Your Bra Size
Now, 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:
For example, if your band size is 34 inches and your bust size is 36 inches, the difference is 2 inches, making your bra a B cup size. Your full bra size would be 34B.
- 1 inch difference = A cup
- 2 inches difference = B cup
- 3 inches difference = C cup, and so on.
Use our bra measurement chart below to find the corresponding size in different regions:
Cup Size Chart
| Difference in (cm) | UK | US | EU | FR | AU |
|---|---|---|---|---|---|
| <1 | AA | AA | AA | AA | AA |
| 1 (2.5) | A | A | A | A | A |
| 2 (5.1) | B | B | B | B | B |
| 3 (7.6) | C | C | C | C | C |
| 4 (10.2) | D | D | D | D | D |
| 5 (12.7) | DD | DD/E | E | E | DD |
| 6 (15.2) | E | DDD/F | F | F | E |
| 7 (17.8) | F | DDDD/G | G | G | F |
| 8 (20.3) | FF | H | H | H | G |
| 9 (22.9) | G | I | I | I | H |
| 10 (25.4) | GG | J | J | J | I |
| 11 (27.9) | H | K | K | K | J |
| 12 (30.5) | HH | L | L | L | K |
| 13 (33.0) | J | M | M | M | L |
| 14 (35.6) | JJ | N | N | N | M |
| 15 (38.1) | K | O | O | O | N |
| 16 (40.6) | KK | P | P | P | O |
| 17 (43.2) | L | Q | Q | Q | P |
| 18 (45.7) | M | R | R | R | LL |
For a full bra size guide chart with sizes for different countries and brands, visit brasizecalculator.com/chart.
Use our online bra size calculator in inches to quickly determine your size without manual calculations.
Step 4: Use our Bra Size Calculator
Start by using our online bra size calculator on the left side of your screen. Enter your band and bust measurements into the calculator.
Be sure to pick your preferred measurement unit, either inches or centimeters. The calculator will provide:
- Your recommended bra size.
- Two additional sister sizes to help you find the most comfortable fit across different brands and styles.
- Recommended brands for the calculated size.
- Style recommendations such as strapless bras, plunge bras, wireless bras, and push-up bras tailored to your size.
Self Calculation
If you'd rather calculate your bra size by hand, just combine the band size you measured with the cup size from the chart.
You can find a full bra size chart with sizes for different countries and brands at brasizecalculator.com/chart. The chart is also available in printable image form for quick reference.
For example, if your band size is 38 and your cup size is F, then your full bra size would be 38F.
This method lets you double-check the calculator’s result for a better fit.
Special Note on Traditional Calculation Methods
Some brands use a traditional method to find band size, where they add 4 inches to your underbust measurement.
For example, if your band measurement is 34 inches, these brands would calculate your band size as 38.
This can be different from modern methods, so it’s helpful to know the sizing approach of each brand.
Step 5: Try on Bras for Fit
Once you have your calculated bra size, try on different bras in that size to see what feels comfortable and supportive.
Remember, sizing can vary between brands and styles, so try a few options to find your best fit.
Frequently Asked Questions
- Band Size: Measure around your ribcage, just under your bust. Make sure the tape is snug but not too tight.
- Bust Size: Measure around the fullest part of your bust, making sure the tape is parallel to the floor and not too loose.
