Size chart
Little Sleepies baby size chart
Little Sleepies publishes 10 baby and toddler sizes, Preemie to 4T, by weight and height. A separate sleepwear chart is included. Checked against littlesleepies.com on October 4, 2026.
Size chart
- Preemieup to 5 lb
- Newborn5 to 8 lb
- 0-3M8 to 12 lb
- 3-6M12 to 17 lb
- 6-12M17 to 23 lb
- 12-18M23 to 26 lb
- 18-24M26 to 30 lb
- 2T29 to 31 lb
- 3T31 to 35 lb
- 4T35 to 39 lb
Weight in lb, exactly as Little Sleepies publishes it.
Does Little Sleepies run small or large?
True to sizeAcross 9 size labels that other brands also use, Little Sleepies' 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 Little Sleepies
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 | Little Sleepies 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 | 6-12M |
| 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 Little Sleepies' chart, size by size.
| Size | Weight | Height or length | Age |
|---|---|---|---|
| Preemie | Up to 5lbs | Up to 18" | Not published |
| Newborn | 5-8lbs | 18-21" | Not published |
| 0-3m | 8-12lbs | 21-23" | Not published |
| 3-6m | 12-17lbs | 23-27" | Not published |
| 6-12m | 17-23lbs | 27-31" | Not published |
| 12-18m | 23-26lbs | 31-33" | Not published |
| 18-24m | 26-30lbs | 33-34.5" | Not published |
| 2T | 29-31lbs | 33-36" | Not published |
| 3T | 31-35lbs | 36-39" | Not published |
| 4T | 35-39lbs | 39-42" | Not published |
| Size | Weight | Height or length | Age |
|---|---|---|---|
| Micro Preemie | Up to 3lbs | Up to 15" | Not published |
| Preemie | 3-5lbs | 15-18" | Not published |
| Newborn | 5-8lbs | 18-21" | Not published |
| 0-3m | 8-12lbs | 21-23" | Not published |
| 3-6m | 12-17lbs | 23-27" | Not published |
| 6-9m | 17-20lbs | 27-29" | Not published |
| 6-12m | 17-23lbs | 27-31" | Not published |
| 12-18m | 23-26lbs | 31-33" | Not published |
| 18-24m | 26-30lbs | 33-34.5" | Not published |
| 2T | 29-31lbs | 33-36" | Not published |
| 3T | 31-35lbs | 36-39" | Not published |
Notes on this chart. The clothing chart is the brand's Play (daywear) chart. The sleepwear chart is the Zippy one-piece pajama chart, which adds Micro Preemie and a 6-9m size. The brand also publishes a separate chart for two-piece pajama sets, which it says are cut slim; that chart is not included. Published ranges overlap between 18-24m and 2T.
Sources
- Brand's own site: https://littlesleepies.com/pages/sizing-guide
Retrieved October 4, 2026. Brands update their charts, so check the brand's page before a big purchase. This site is not affiliated with Little Sleepies.
Calculator
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