Size chart
Posh Peanut baby size chart
Posh Peanut publishes 12 baby and toddler sizes, Preemie to 4T, by weight and height. Checked against poshpeanut.com on October 4, 2026.
Size chart
- Preemie0 to 6 lb
- Newborn6 to 9 lb
- 0-3M9 to 12 lb
- 3-6M12 to 17 lb
- 6-9M17 to 20 lb
- 6-12M17 to 22 lb
- 9-12M20 to 22 lb
- 12-18M22 to 25 lb
- 18-24M25 to 27 lb
- 2T28 to 30 lb
- 3T31 to 34 lb
- 4T34 to 39 lb
Weight in lb, exactly as Posh Peanut publishes it.
Does Posh Peanut run small or large?
True to sizeAcross 11 size labels that other brands also use, Posh Peanut's published ranges sit close to the middle of the pack. The same label covers about the same baby.
Based on published size charts compared with other brands. This is not a fit review.
What a typical baby wears in Posh Peanut
For a baby in the middle of the WHO growth chart, with room to grow. Your baby's own measurements give a closer answer in the calculator below.
| Age | Typical weight | Typical length | Posh Peanut size |
|---|---|---|---|
| Birth | 7.3 lb | 19.5 in | Newborn |
| 3 months | 13.5 lb | 23.9 in | 3-6M |
| 6 months | 16.8 lb | 26.2 in | 3-6M |
| 9 months | 18.9 lb | 28 in | 6-12M |
| 12 months | 20.5 lb | 29.5 in | 9-12M |
| 18 months | 23.3 lb | 32.1 in | 12-18M |
| 2 years | 26.1 lb | 34 in | 2T |
| 3 years | 31.1 lb | 37.6 in | 3T |
The chart as published
The original wording from Posh Peanut's chart, size by size.
| Size | Weight | Height or length | Age |
|---|---|---|---|
| Preemie | 0-6 lbs | UP TO 17 inches | Not published |
| Newborn | 6-9 lbs | UP TO 21.5 inches | Not published |
| 0-3 Months | 9-12 lbs | 21.5-24 inches | Not published |
| 3-6 Months | 12-17 lbs | 24-26.5 inches | Not published |
| 6-9 Months | 17-20 lbs | 26.5-29 inches | Not published |
| 6-12 Months | 17-22 lbs | 26.5-31 inches | Not published |
| 9-12 Months | 20-22 lbs | 29-31 inches | Not published |
| 12-18 Months | 22-25 lbs | 31-33 inches | Not published |
| 18-24 Months | 25-27 lbs | 33-34 inches | Not published |
| 2T | 28-30 lbs | 34-36 inches | Not published |
| 3T | 31-34 lbs | 36-39 inches | Not published |
| 4T | 34-39 lbs | 39-42 inches | Not published |
Notes on this chart. One chart covers all baby and children's clothing. 6-12 Months overlaps 6-9 Months and 9-12 Months as published. Preemie weight is printed as 0-6. A combined 3T-4T transitional size (31-39 lbs, 36-42 inches) is published separately and not included.
Sources
- Brand's own site: https://poshpeanut.com/pages/size-chart
Retrieved October 4, 2026. Brands update their charts, so check the brand's page before a big purchase. This site is not affiliated with Posh Peanut.
Calculator
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