Quick Answer
To measure cup size, measure your bust at the fullest point, measure your underbust for band size, then subtract band from bust. The difference is used to estimate the cup letter on a cup size chart.
For the standard method, use the standard bra size measuring method as your main reference.
When This Method Makes Sense
- You already know your band measurement and need the cup estimate.
- You want to understand why bust size and cup size are not the same thing.
- You are comparing calculator results with a cup size chart.
Step-by-Step Instructions
- Measure your underbust to get the band measurement.
- Measure your bust around the fullest part while keeping the tape level.
- Subtract the band measurement from the bust measurement.
- Compare the difference with a cup size chart for your sizing system.
- Try the calculated size and adjust based on cup fit.
Mistakes to Avoid
- Treating bust measurement alone as cup size.
- Comparing cup letters across different band sizes as if they hold the same volume.
- Using a padded or push-up bra for the bust measurement.
- Ignoring the sizing system when reading a cup chart.
When to Use the Calculator
Use the calculator if you want the band and cup estimate handled together. Use a chart when you want to see how the bust-band difference maps to cup letters.
Open the bra size calculator after you have both your band and bust measurements.
Frequently Asked Questions
Is cup size the same as bust size?
No. Bust size is a body measurement. Cup size is estimated from the difference between bust and band measurements.
What if my difference falls between cup sizes?
Use the closest cup as a starting point, then check the actual fit. Brand shape, fabric, and breast shape can make either nearby size work better.
Do cup letters mean the same volume on every band?
No. Cup volume changes with band size, which is why sister sizes can have similar volume with different band and cup labels.