How to Measure Bra Size at Home for a Perfect Fit

Quick answer

To measure your bra size at home, wear a non-padded bra and use a soft tape measure. Measure your band size snugly around your ribcage just under your bust, then measure your bust at the fullest point. Subtract band from bust to find your cup size. Always cross-check with each brand's size chart, because sizing varies—especially in wireless, plastic-free bras.

A bra that fits well shouldn't dig in, ride up, or leave you adjusting all day. Yet many of us wear the wrong size because we guess or rely on old measurements. The good news: you can learn how to measure bra size at home in about five minutes with just a soft tape measure and a mirror.

This bra fitting guide walks you through each step, from measuring your band size to measuring your cup size, and explains how to interpret the numbers. We'll also cover common mistakes and how to adapt the method for wireless, natural-fibre bras like the ones we make at The Very Good Bra.

What you'll need

Before you start, gather a soft tape measure (the flexible kind used for sewing), a mirror, and a non-padded bra you already own. If you don't have a soft tape, you can use a piece of string and then measure it against a ruler. Wear a thin, unpadded bra—or no bra if you prefer—so the tape sits close to your body without compressing breast tissue.

A full-length mirror helps you keep the tape level all the way around. It's also useful to have a pen and paper or your phone to note the numbers. Avoid measuring over thick clothing or a padded bra, as this adds inches and skews your result.

• Use a soft tape measure, not a metal one.
• Wear a non-padded bra or no bra.
• Stand in front of a mirror to check the tape is level.

Step 1: Measure your band size

Wrap the tape around your ribcage, directly under your bust. The tape should be snug—firm against your skin but not digging in—and level all the way around. Breathe normally and exhale before you read the number. This is your underbust measurement. Round it to the nearest whole inch or centimetre.

If the number is even, add 4 inches (or 10 cm) to get your band size. If it's odd, add 5 inches (or 12 cm). For example, a 30-inch underbust gives a 34 band; a 31-inch underbust gives a 36 band. Some modern brands use your exact underbust measurement as the band size, so always check the brand's size chart.

• Common mistake: pulling the tape too tight. It should feel snug, not painful.
• Checkpoint: the tape should be parallel to the floor all the way around.

Step 2: Measure your bust size

Wrap the tape around the fullest part of your bust, usually across the nipple line. Keep the tape level and not too tight—it should just rest against your bust without compressing it. Stand straight with your arms down. Read the number in the mirror or ask someone to help.

This is your bust measurement. Write it down alongside your band measurement. If you're between sizes, note both and use them when checking a brand's size chart. For wireless bras, your bust measurement may be more reliable than for underwired styles because there's no wire to distort the fit.

• Common mistake: measuring over a padded bra, which adds volume.
• Checkpoint: the tape should not slip down at the back.

Step 3: Calculate your cup size

Subtract your band measurement (the number before adding 4 or 5 inches) from your bust measurement. The difference in inches determines your cup size: 1 inch = A, 2 inches = B, 3 inches = C, 4 inches = D, 5 inches = DD/E, 6 inches = DDD/F, 7 inches = G, and so on. For example, a 34 band with a 37-inch bust is a 34C.

If you're using centimetres, the same principle applies but the cup increments are roughly 2.5 cm per cup. However, most brands use inch-based cup sizing. Remember that cup size is not static—it changes with band size. A 34C and a 36B have similar cup volumes but different band lengths.

• Common mistake: using the band size after adding 4-5 inches to calculate cup size. Always use the original underbust measurement.
• Checkpoint: if the difference is less than 1 inch, you may be an AA cup.

Step 4: Try on and adjust

Use your measurements as a starting point, not a rule. Try on a bra in your calculated size and check the fit: the band should be level and snug, the centre front should lie flat against your sternum (for underwired styles), and the cups should contain your breast tissue without spilling or gaping. If the band rides up, go down a band size. If the cups overflow, go up a cup size.

For wireless bras, the band does more of the support work, so a snug fit is essential. If you're between band sizes, consider sizing down because natural-fibre bras can relax slightly with wear. Our V for Victory Bra - Rum & Raisin with removable pads has a sizing note: it has a little more stretch in the band than other styles, so if you're on the cusp between band sizes, we recommend sizing down one band in this colour.

• Common mistake: assuming your size is the same across all brands.
• Checkpoint: the band should not leave red marks or feel restrictive.

Step 5: Re-measure periodically

Your bra size can change with weight fluctuations, hormonal changes, pregnancy, and ageing. Re-measure every six months or whenever you notice your bras feeling different. A quick five-minute check can save you from discomfort and extend the life of your bras.

If you're buying a bra with removable pads, like the V for Victory Bra - Rum & Raisin with removable pads, remember that the pads can add a little volume. Measure without pads for the most accurate starting point, then adjust if needed.

• Common mistake: sticking to the same size for years without re-checking.
• Checkpoint: if you're constantly adjusting straps or the band, it's time to re-measure.

Your at-home measuring checklist

1. Gather your tools: Soft tape measure, mirror, non-padded bra, pen and paper. Checkpoint: tape is flexible and not stretched out.
2. Measure your band: Snug around ribcage under bust, level all around. Round to nearest whole number. Common mistake: tape too tight or too loose.
3. Measure your bust: Around fullest part, tape level and not compressing. Checkpoint: tape stays parallel to floor.
4. Calculate cup size: Subtract band from bust; each inch equals one cup size. Common mistake: using adjusted band size instead of original underbust.
5. Try on and adjust: Check band level, cups smooth, centre flat. Adjust size as needed. Checkpoint: you can fit two fingers under the band.
6. Re-measure every 6 months: Body changes affect size; a quick check ensures comfort. Next step: note your size and check brand-specific charts.

How our bras fit into your measurements

• V for Victory Bra - Rum & Raisin with removable pads: A wireless, full-coverage bra in a warm, rich brown - to wear with or without removable pads, in sizes up to a G cup. Made from 100% Lenzing TENCELTM with all-natural, plastic-free materials throughout. Wireless bras rely on the band for support, so an accurate band measurement is key. The removable pads let you adjust coverage without changing your size.
• Wisteria Bra: By popular request, a beautiful new Blue Bra in a deep wisteria colour. This is the same style and fit as our original launch Black Tencel Bra, as well as it's beloved cousin, Vintage Peach. Made with the softest organic cotton knitted and ACO (Australian Certified Organic) dyed here in Australia. All materials are 100% plastic-free, natural fibres, with no spandex or polyester ANYWHERE! Natural fibres without spandex have less stretch, so the band should feel snug but not tight. If you're between sizes, you may prefer the larger band for comfort.

Measuring your bra size at home is a simple skill that pays off in comfort and confidence. Use this bra fitting guide to find your band and cup size, then cross-check with the brand's size chart. Remember that wireless, plastic-free bras may fit slightly differently, so don't hesitate to try a couple of sizes. With accurate measurements, you're on your way to a perfect bra fit.