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Bra Size Calculator

Use a flexible tape measure. Choose inches or centimeters, then enter your underbust (snugly under the breasts) and bust (around the fullest part). Accuracy within 0.5 cm or 1/4 in helps.

Measure directly under the bust, level around your torso. Keep the tape parallel to the floor and breathe out gently for a snug reading.

Measure around the fullest part of your bust without compressing breast tissue. Keep the tape level and comfortable.

Fit preference adjusts the final band size rounding slightly. You can compare sister sizes if you’re between sizes.

Tip: Wear a non-padded bra while measuring. If your numbers vary, take the average of two to three measurements.

Bra Size Calculator

Find your accurate bra size quickly and confidently. Our Bra Size Calculator uses your underbust and bust measurements, in inches or centimeters, to estimate your band and cup size and offer practical fit guidance.

How the Bra Size Calculator Works

The calculator uses two essential measurements: underbust (the ribcage measurement directly beneath the breasts) and bust (the fullest part of the chest). After you choose your measurement unit, enter both values as accurately as possible. The tool converts centimeters to inches where needed, estimates the closest even band size, and calculates the cup size from the difference between your bust and band.

Because bodies vary, we include a fit preference option. Selecting a snug band will slightly reduce the recommended band size, while choosing a looser band increases it. This helps you fine-tune comfort and support without guessing. If you’re between sizes, try sister sizes: going down a band means going up a cup, and going up a band means going down a cup.

How to Measure for the Best Result

1) Underbust (Band) Measurement

  • Stand straight, breathe out gently, and wrap the tape measure under your bust.
  • Keep the tape level and snug, but not painfully tight.
  • Record to the nearest 0.5 cm or 1/4 inch.

2) Bust (Overbust) Measurement

  • Measure around the fullest part of your bust.
  • Keep the tape parallel to the floor and comfortably against the body.
  • Wear a lightly lined or unpadded bra for consistency.

Repeat each measurement two or three times and average the results for greater accuracy. If you notice your measurements change throughout the day, measure at a consistent time, such as in the morning.

Interpreting Your Results

Your band size is the foundation of your bra fit. It should provide most of the support while sitting level around the body. If it rides up your back, the band is likely too loose. If it digs in uncomfortably, it may be too tight. Straps should rest on your shoulders without slipping or cutting in; if they do, adjust them after you confirm the correct band and cup.

The calculator determines cup size by the difference between your bust and your calculated band size. Each inch of difference generally corresponds to a cup step (A, B, C, D, DD/E, DDD/F, and so on). Remember, cup volume depends on the band: a 32C and a 36C do not hold the same volume. That’s why sister sizing is useful.

Common Fit Tips and Adjustments

  • If the center gore (the piece between the cups) doesn’t lie flat, try a larger cup or a different style.
  • If cups wrinkle or gap, the cup may be too large; if they overflow, the cup is too small.
  • For asymmetry, fit the larger side and use a removable insert on the smaller side.
  • Try different styles—balconette, plunge, full coverage—since shape and wire width affect comfort.

Why Accurate Sizing Matters

A well-fitted bra improves posture, comfort, and garment appearance. It can reduce shoulder and back strain, prevent strap slippage, and help clothing drape correctly. Accurate sizing also extends the life of your bras by reducing excessive stretching and fabric stress.

When to Recheck Your Size

Re-measure every 6–12 months, or after significant weight changes, hormone shifts, pregnancy, or athletic training. Elastic materials relax over time, so reassessing your size and replacing worn bands can restore support.

From Measurement to Confidence

Use the Bra Size Calculator anytime your current bras feel off. With precise measurements, a clear band and cup estimate, and helpful fit tips, you’ll be closer to a supportive, comfortable, and flattering fit. If your result sits between sizes, explore sister sizes and styles to fine-tune comfort. The right fit is a combination of numbers, body shape, and personal preference—and this tool is your starting point.

FAQs

How do I measure for the Bra Size Calculator?

Measure underbust snugly under your bust and bust at the fullest point, then enter both values in the Bra Size Calculator.

Does the Bra Size Calculator work with centimeters?

Yes. Choose centimeters in the dropdown and the Bra Size Calculator converts to inches automatically.

What does the fit preference do in the Bra Size Calculator?

It slightly adjusts the band rounding in the Bra Size Calculator for a snugger or looser fit.

How accurate is the Bra Size Calculator for cup sizes?

The Bra Size Calculator provides a close estimate; try sister sizes and different styles to fine-tune fit.

Can the Bra Size Calculator suggest sister sizes?

Yes, the Bra Size Calculator outputs nearby sister sizes to help if you are between sizes.

What if my Bra Size Calculator result feels too tight?

Try the looser fit option or a sister size up in the Bra Size Calculator: +2 band and one cup down.

Should I wear a bra while using the Bra Size Calculator?

A lightly lined, non-padded bra gives the most consistent measurements for the Bra Size Calculator.

Why does the Bra Size Calculator use even band numbers?

Most US/UK band sizes are even numbers; the Bra Size Calculator rounds to the nearest even for consistency.