Measuring Guide

How to Measure Bra Size at Home

Updated March 2026

Learning how to measure bra size at home takes just two minutes and a soft measuring tape. Follow the steps below for an accurate result you can trust every time you shop.

What You'll Need

A soft fabric measuring tape (not a rigid one). If you don't have one, use a piece of string and measure it against a ruler afterward. Wear a non-padded bra or no bra for the most accurate result.

Woman demonstrating how to position a measuring tape for bra sizing
1

Measure Your Underbust

Wrap the tape snugly around your ribcage, directly below your breasts. It should be level all the way around and firm enough that it doesn't slide, but not so tight it digs in. Round to the nearest whole number. This is your band size.

Woman measuring her underbust with a soft measuring tape in a bright bathroom, demonstrating step 1 of finding your bra size

Keep the tape level all the way around and snug against your skin — you should be able to fit one finger underneath but not two. This is the first step in how to measure bra size correctly, and this number becomes your band size.

2

Measure Your Bust

Wrap the tape around the fullest part of your bust, keeping it level and parallel to the floor. Don't pull tight — the tape should sit gently against your skin. Round to the nearest whole number.

3

Calculate the Difference

Subtract your underbust from your bust measurement. Each inch of difference equals one cup size: 1" = A, 2" = B, 3" = C, 4" = D, 5" = DD, and so on. Combine your band number with your cup letter for your full size (e.g., 34C). Now you know how to measure bra size — enter your numbers into our calculator for instant results.

Once you have both numbers, use our bra size calculator to find your size in US, UK, EU, and AU systems — or check the breast size chart to look up your size manually.

Skip the +4 method. Some older fitting guides tell you to add 4 inches to your underbust. This outdated method typically results in a band too loose and a cup too small. Modern sizing uses your actual underbust measurement as the band.
Soft measuring tape on marble surface used for taking accurate bra measurements at home

Tips for an Accurate Measurement

Knowing how to measure bra size accurately means paying attention to a few important details. Follow these tips for the best results.

Stand naturally

Don't puff your chest out or slouch. Stand the way you normally would — that's the body your bra needs to fit.

Measure twice

Take each measurement at least twice to confirm. When learning how to measure bra size, remember that even a half-inch difference can shift you into a different cup size.

If your breasts are different sizes

Measure the larger side and fit to that. Most women have slight asymmetry — it's completely normal. A bra that fits the larger breast will be more comfortable.

When to remeasure

Your bra size can change with weight fluctuation, hormonal changes, pregnancy, and age. Remeasure every 6–12 months or whenever your current bras feel off. Not sure which international system to use? Check our bra size converter for US, UK, EU, and AU translations.

Close-up of a woman in a white lace bra wrapping a gold measuring tape around her underbust for accurate bra size measurement

For the most accurate results, measure in a well-fitting unpadded bra or no bra at all. Padded or push-up bras will add volume and skew your bust measurement.

Now that you know how to measure bra size, find your exact fit.

Use the Calculator →