The standing measurement
- Stand upright with your arms relaxed at your sides.
- Pass the tape around your back and bring it over the fullest part of your bust. For most people that is across the nipples.
- Check in a mirror that the tape is level at the back. It tends to ride up there.
- Let the tape rest on the skin. It should not flatten or dent the breast.
- Read the number without rounding.
The leaning measurement
Stand with your feet apart and bend at the hips until your back is parallel with the floor. Let your breasts hang freely. Wrap the tape around your back and under the fullest part, keeping it at right angles to your spine, and read the number.
It is awkward the first time. Holding the tape ends together at the side makes it easier to read without straightening up.
Who needs it
Everyone can benefit from the check, and it matters most if:
- your breasts are soft, or have changed after pregnancy, breastfeeding or weight loss,
- they sit lower on your chest without a bra, or
- calculators keep giving you a cup that turns out too small.
The lying measurement
Lie flat on your back and measure across the fullest part. Tissue spreads sideways in this position, so the reading is often the smallest of the three. It is a useful counterweight to the leaning figure, which for very soft tissue can run a little high.
Combining them
| What you find | Use as your bust figure |
|---|---|
| Standing and leaning within 1 inch | The standing measurement |
| Leaning 1 to 2 inches bigger | The average of standing and leaning |
| Leaning more than 2 inches bigger | The average of all three |
These are working rules, not a formula with any official standing. Each inch is one cup size, so where the readings disagree, expect to try two neighbouring cups.
An example
Band 32. Standing 37 inches, leaning 39½, lying 37½. The leaning figure is more than two inches above the standing one, so average all three: 38. That is 6 inches over the band, an E cup. The standing measurement alone would have said DD.
Common mistakes
- Pulling the tape tight. This is the bust, not the underbust. Compression makes the cup come out too small.
- Measuring in a padded bra. You add the padding to your result.
- Measuring in a sports bra or minimiser. They flatten the bust and take inches off.
- Letting the tape rise at the back.
- Measuring during a few days of unusual swelling and treating it as your everyday size, or the reverse. If you fluctuate with your cycle, note both.
From measurement to cup
Subtract your band size from your bust figure. Each inch is one UK cup: 1 is A, 2 is B, 3 is C, 4 is D, 5 is DD, 6 is E, 7 is F. The calculator does this for you, and the complete walk-through is in how to measure your bra size.
Frequently asked questions
Should I measure my bust with or without a bra?
Without one if you can, especially for the leaning measurement. If you prefer to keep one on, it must be thin, unpadded and not a minimiser or sports bra, and it should already fit reasonably well.
Why is my leaning bust measurement bigger than my standing one?
Because leaning forward lets all the breast tissue hang away from the chest, where the tape can go round it. Standing, softer tissue settles downward and some of its volume is missed. A larger leaning figure is normal and means the standing figure alone would give you too small a cup.
Which bust measurement should I use?
If standing and leaning are within an inch of each other, use the standing one. If they are further apart, average them, or average all three including the lying measurement.
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