How to Measure Your Underbust & Overbust at Home
Follow these measurement checkpoints to capture snug, tight, and relaxed underbust readings, confirm overbust depth, and convert everything into the right band size.
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Tools you need before measuring
Set up these items so you are not juggling gear while holding the tape.
- Soft, flexible measuring tape marked in inches and centimeters.
- A non-padded bra that already fits comfortably.
- A full-length mirror to verify tape placement stays level.
- Notebook or notes app to log snug, tight, relaxed, and overbust readings.
How to measure your underbust
Use the same tape path for every pass: parallel to the floor, resting directly under the breast root.
- Snug underbust: Exhale gently, tighten the tape until it is secure but not digging, and record the number. This anchors your everyday band size.
- Tight underbust: Pull the tape one notch tighter to find the lowest band you can reasonably wear. Compare with the snug value when deciding between sister sizes.
- Relaxed underbust: Loosen the tape until it just touches the skin. If this differs greatly from the snug value, prioritize comfort-first bands or styles with extra hooks.
- Check alignment: Use the mirror to ensure the tape stays level front to back. Tilted tapes add inches and cause inaccurate band labels.
Want another walkthrough? Read the detailed band section inside our at-home bra size guide.
Capture your overbust for cup depth
Overbust readings tell you how much volume sits on top of the band. They work hand in hand with underbust numbers to produce a cup size.
- Standing bust: Stand tall, keep arms relaxed, and place the tape across the fullest point (usually nipple level). This is the baseline cup measurement.
- Leaning bust: Bend forward to 90 degrees and re-measure. The leaning value captures tissue that settles toward the chest when upright—critical for fuller or projected busts.
- Lying bust: Lie flat on your back and measure again to understand how shallow bras might fit. Use this if you struggle with cup gaping.
Need a visual for these angles? Our bust measurement guide includes photos and troubleshooting tips.
Band size conversion table
Match your snug underbust to the closest range to pick your starting band. If you land at the top of a range, note the tighter sister size as a backup.
| Snug underbust | UK/US band label | EU / JP equivalent |
|---|---|---|
| 26.5 – 27.5 in (67–70 cm) | 28 band (UK/US) | 60 EU/JP |
| 28.5 – 29.5 in (72–75 cm) | 30 band (UK/US) | 65 EU/JP |
| 30.5 – 31.5 in (77–80 cm) | 32 band (UK/US) | 70 EU/JP |
| 32.5 – 33.5 in (82–85 cm) | 34 band (UK/US) | 75 EU/JP |
| 34.5 – 35.5 in (87–90 cm) | 36 band (UK/US) | 80 EU/JP |
| 36.5 – 37.5 in (92–95 cm) | 38 band (UK/US) | 85 EU/JP |
| 38.5 – 39.5 in (97–100 cm) | 40 band (UK/US) | 90 EU/JP |
| 40.5 – 41.5 in (102–105 cm) | 42 band (UK/US) | 95 EU/JP |
For FR labels add 15 to the EU band (example: 75 EU becomes 90 FR). AU labels subtract 22 from the UK/US band (example: 34 band becomes AU 12).
Common underbust mistakes to avoid
- Measuring over clothing or sports bras that add bulk.
- Letting the tape ride up at the back, which inflates the reading and leads to loose bands.
- Skipping the tight underbust check—this is the easiest way to confirm if you should size down in the band.
- Only using inch values when you shop in EU cm-based systems. Record both units to stay flexible.
Next steps after measuring
Enter your snug underbust, bust, leaning, and lying values into the Bra Size Calculator to see multi-system results, breast volume estimates, and sister size suggestions.
If the band result feels tight or loose, try the sister sizes shown in the calculator or visit the Bra Fit Check wizard for strap, gore, and cup troubleshooting tips.
Want brand-specific conversions? Jump to the Brand Size Converter and translate your band label for global retailers.
Underbust & overbust FAQ
What is the difference between a snug, tight, and relaxed underbust?
Snug is your everyday anchor measurement taken on an exhale, tight is slightly firmer to see how low you can go on the band, and relaxed checks breathing room. Compare all three when deciding between sister sizes.
How should I measure my overbust if I have a fuller bust?
Take three overbust readings—standing, leaning forward 90 degrees, and lying on your back. Use the leaning value to confirm cup depth for fuller shapes and the lying value to see how shallow bras may fit.
How do I convert my underbust measurement into an international band size?
Round your snug underbust to the nearest range in the table, then match the UK/US band to its EU/JP and FR (EU + 15) equivalents. You can also use the Bra Size Calculator to view conversions for AU and IT labels.