A 31 in women’s jeans usually means:

  • A jeans waist size of about 31–33 inches, depending on brand and rise.
  • In many US “pants sizes,” this lines up roughly with around a size 12/13 or 12–14, again varying by brand and cut.
  • In UK sizing, several converters place a size 31 jean close to about a UK 12–14.

Quick size snapshot (approx.)

Measure / Label| Typical value for “31” women’s jeans
---|---
Jeans waist label| 31 in 3
Actual waist (body)| About 32–33 in 35
US pants size| Around 12/13 or 12–14 13
UK size| Around UK 12–14 37

Why it’s confusing

  • Different brands use vanity sizing and cut (high‑rise vs low‑rise), so the same “31” can feel tighter or looser from store to store.
  • Stretch denim, mom jeans, skinnies, and wide‑legs all fit differently at the same number size.

How to check if 31 is your size

  1. Measure your natural waist (smallest part of torso) in inches.
  2. If you’re around 31–33 inches, a size 31 jean is often in your range in many brands.
  1. Check each brand’s online size chart and match your waist (and hip) to their 31 column for the best fit.

In everyday terms: if your waist is low‑30s in inches and you usually wear around a US 12 ish in bottoms, a 31 in women’s jeans is probably the ballpark size to start with, then fine‑tune by brand and cut.

Information gathered from public forums or data available on the internet and portrayed here.