So you can buy ahead!

Kids Size Predictor

Kids Size Predictor

for 0-36 Months

Welcome! Kids grow so fast, it’s nice to be able to buy a year or season ahead of time, but it’s annoying to try to do guess work or pull out the your growth curve from the doctor’s office just to try to buy a sweater in the right size!

Please see some of the model’s base and limitations below, or you might be unhappy! I assume no liability for items purchased based on this calculator’s information.

If you appreciate this and want to send support, there are a couple of ways: Shop my Poshmark, buy some Rothy’s, or find me on Venmo @cremiholt.

I created this calculator using finessed data from the CDC (publicly available!) that allows you to put in the basics and make a reasonable estimate of what size your kids will be on the date you input. As a reminder, for actually measuring growth, U.S. pediatricians tends to use the WHO 0-24 month chart, so this data is a bit different than that!

Some limitations to consider! Please only use if your child is on the standard growth chart or understand the limitation of the calculation is that they can only tell you up to the 97th percentile and down to the 3rd percentile. Essentially, it takes where your child is now on the chart and keeps them at that same place as they age. In terms of its rounding, it rounds to the closest half month in age. The CDC only provides data on the half month (1.5, 2.5, etc), so the full months are based on averages of the closest half months. At the end, it rounds up to the nearest pound and full inch.

Finally, this is meant to only cover the period of 0-36 months. It will max out at the value for 36 months even if you put in 5 years, etc. Don’t blame me if you can’t do that math for yourself! I hope to add on to the calculator in time.