Sizing Chart

First Threads products tend to fit bigger/ more true to size than traditional baby brands.

Please refer to the sizing chart below - measurements are in cm:

If your child is, well, a child, and measuring seems impossible - here are two anecdotal scenarios to help you decide sizing:

Baby #1

  • Typically weighs in the 85th to 90th percentile for age.
  • Average height but solid build.
  • Wears true to age size.

Baby #2

  • Weight & height tend to fall around the 20th percentile for age.
  • Very slender with a long torso.
  • Can either wear one age size down or roomy true to age size in tops.
  • Wears one age size down in pants (too slim for the waistband in true to age size).