A **bra calculator** can be used to help determine bra size. The big caveat is that most bra calculators are absolute garbage; they're so bad as to be completely useless.

## How to tell if a calculator is inaccurate

Signs of a bad bra calculator include:

- If it tells you to measure your "overbust", or under your armpits
- If, in UK and US calculators, the band size is several numbers larger that the number you put as your ribcage or underbust measurement (ex: Your ribcage measures 38 but the calculator tells you to wear a 42)
- If, in EU/JP calculators, it says the number you measured your ribcage as is the same as your band size (ex: your ribcage measures 65cm, and the calculator says to wear a 65). The EU/JP sizing system has "plus four" built into it

## Bra fit calculators

There are a few fit calculators that yield accurate results.^{[1]}

- SizemApp Bra Size Calculator using 6 sets of different measurements, most accurate
- "Bra Calculator", the most commonly used calculator from A Sophisticated Pair (use "very snug" setting)
- "Bra Size Calculator", a calculator from Butterfly Collection Lingerie
- "Bra Size Calculator v2", created by an A Bra That Fits user
- "Calculadora de Tallas", a Spanish calculator by Dando La Talla.