Baby Clothing Sizes, From Newborn to 3T
Baby clothes are labeled by age (NB, 0-3M, 12M) but fit by weight and height; newborn size ends around 8 pounds, and the T in 3T means toddler.
By Amanda RoseContributing writer.
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The short answer
A baby size label names an age, but the age is only a guide. What the maker actually designs for is a weight and height range, printed on its size chart. Babies grow at different speeds, so a 4-month-old may already wear 6-9M. Check your baby's latest weight and length (the numbers from the last checkup work well) against the brand's chart.
Baby clothes size chart
These ranges come from Gerber Childrenswear's chart, which runs from preemie to toddler sizes:
| Size | Weight | Height |
|---|---|---|
| Preemie | Up to 5 lb | Up to 17 in |
| Newborn (NB) | 5 to 8 lb | 17 to 21 in |
| 0-3M | 8 to 12 lb | 21 to 24 in |
| 3-6M | 12 to 16 lb | 24 to 26 in |
| 6-9M | 16 to 20 lb | 26 to 28 in |
| 12M | 20 to 24 lb | 28 to 30 in |
| 18M | 24 to 28 lb | 30 to 32 in |
| 24M / 2T | 28 to 32 lb | 32 to 34 in |
| 3T | 32 to 35 lb | 34 to 38 in |
| 4T | 35 to 39 lb | 38 to 40 in |
| 5T | 39 to 43 lb | 40 to 44 in |
Gerber also sells a 0-6M size, up to 16 pounds, that covers both 0-3M and 3-6M. Other brands draw the lines a little differently, so a 6-9M from one label can fit like a 6M or a 9M from another.
Newborn vs 0-3 months
On this chart, newborn stops at 8 pounds and 21 inches, while 0-3M picks up from 8 to 12 pounds and up to 24 inches. A baby born at 8 pounds or more may skip newborn size, or wear it only briefly.
Gerber's own advice for gifts follows from that: new parents usually receive most clothes in newborn and 0-3M, so a larger size such as 3-6M is often more useful. When in doubt, the brand suggests sizing up, since a baby grows into loose clothes but is hard to keep comfortable in tight ones.
What does 3T mean
The T stands for toddler. Toddler sizes (2T, 3T, 4T, 5T) take over where the month sizes end. On Gerber's chart, 3T fits about 32 to 35 pounds and 34 to 38 inches. 24M and 2T share a row there, but not every brand treats them as the same size, so compare the charts if your child is between the two.
The number is not the child's age. A tall 2-year-old can wear 3T, and a small 3-year-old may still fit 2T.
Pajamas fit differently
Children's sleepwear sold in the US must either resist flame or fit snugly. Federal rules exempt garments sized nine months or smaller, and tight-fitting garments, from the flame-resistance test. That is why many cotton pajamas are cut close to the body, and why Gerber publishes a separate pajama chart. Do not size up in snug-fit pajamas; the close fit is the safety feature.
Shopping on Wiki Shopping
Bodysuits, sleepers and other baby clothes sit under baby products. Read the size chart linked in each listing, and compare it with your baby's weight and height before you choose a size.