Measuring Guide
How to Measure Your Bra Size at Home
For a quick estimate, measure snugly around your ribcage directly under the bust, then measure around the fullest part of the bust without compressing the tissue. Keep the tape level and enter both numbers in the calculator.
Calculate a starting bra size
Enter two measurements for a quick estimate, or switch to advanced mode for a wider, more precise range.
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Advanced fit analysis
Six measurements give a comfort range for the band and a more reliable cup estimate.
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What you need
- A flexible measuring tape.
- A mirror.
- Somewhere to note the numbers - paper or your phone.
- An unpadded bra, or no bra, depending on which method you prefer.
- Optionally, someone to help hold the tape level from behind.
Step 1 - Measure your underbust
Wrap the tape directly under the bust, on the ribcage, where a band would sit. Breathe normally and keep the tape level all the way around - front, sides and back. The tape should feel snug, not tight: you should be able to slide a finger underneath without much resistance. Decimal values (like 33.5) are fine to enter as-is; don't round them.
Step 2 - Measure your bust
Wrap the tape around the fullest point of the bust, without pulling it tight or compressing the tissue. Keep the tape level - it's easy to let it dip at the back without a mirror or a helper. Stand with normal posture; leaning forward or back changes the reading. A padded or moulded bra under the tape will distort this measurement, so measure without one if possible.
For a more detailed result, take six measurements
The quick method above uses two numbers. The advanced mode above uses six, which builds in a comfort range for the band and a more reliable estimate for the cup:
- Loose underbust - breathe out fully, tape comfortably loose.
- Snug underbust - the same measurement as Step 1 above.
- Tight underbust - breathe in, tape pulled snug.
- Standing bust - the same measurement as Step 2 above.
- Leaning bust - leaning forward 90 degrees at the hips.
- Lying bust - lying flat on your back.
Seven measurement mistakes that change the result
- Letting the tape slope up or down instead of staying level.
- Pulling the tape tight enough to compress breast tissue.
- Measuring over a padded or moulded bra.
- Rounding the number before entering it into the calculator.
- Holding your breath or pulling your stomach in while measuring.
- Measuring the underbust too low, below the actual band line.
- Using an old tape that has stretched out and no longer reads accurately.
What if the result looks wrong?
A smaller band with a larger cup letter than you expected is often correct, not a mistake - see why your calculated size might look surprising before re-measuring.
How often should you measure again?
Body measurements can shift with weight changes, hormonal cycles, pregnancy and simply time. See how often to measure your bra size for a practical guideline.