Brand vs brand

Old Navy vs Wonder Nation sizes

Of Old Navy's 10 baby and toddler sizes, 1 line up closely with a Wonder Nation size, 9 are partial matches, and 0 have no clean match. Both charts list weight and height, so the comparison uses both.

Closest pairs: Old Navy 3-6M = Wonder Nation 3-6M.

Watch the labels: Old Navy 0-3M is closer to Wonder Nation 0-3M than to Wonder Nation's own 0-3M; Old Navy 3-6M is closer to Wonder Nation 3-6M than to Wonder Nation's own 3-6M; Old Navy 6-9M is closer to Wonder Nation 6-9M than to Wonder Nation's own 6-9M.

Old Navy True to sizeWonder Nation Runs small

Based on published size charts compared with other brands.

Size by size, on one scale

Each block is one size, placed where the brand's chart puts it. Blocks that sit above each other fit the same baby.

Weight (lb)

Old Navy

Up to 7 lb: up to 6.6 lb
0-3M: 6.6 to 13.2 lb
3-6M: 13.2 to 17.6 lb
6-9M: 17.6 to 19.8 lb
6-12M: 17.6 to 22 lb
12-18M: 22 to 24.3 lb
18-24M: 24.3 to 26.5 lb
2T: 26.5 to 28.7 lb
3T: 28.7 to 33.1 lb
4T: 33.1 to 35.3 lb

Wonder Nation

Preemie: up to 5 lb
Newborn: 5.5 to 7.5 lb
0-3M: 6.5 to 12 lb
3-6M: 12.5 to 16 lb
6-9M: 16.5 to 19 lb
12M: 19.5 to 22 lb
18M: 22.5 to 26 lb
24M: 26.5 to 30 lb
2T: 26.5 to 30 lb
3T: 30.5 to 34 lb
4T: 34.5 to 38 lb

Height (in)

Old Navy

Up to 7 lb: up to 21.7 in
0-3M: 21.7 to 24 in
3-6M: 24 to 26.4 in
6-9M: 26.4 to 29.1 in
6-12M: 26.4 to 29.1 in
12-18M: 29.1 to 31.5 in
18-24M: 31.5 to 33.9 in
2T: 33.9 to 36.2 in
3T: 36.2 to 39 in
4T: 39 to 42.1 in

Wonder Nation

Preemie: up to 17 in
Newborn: 17.5 to 21 in
0-3M: 20.5 to 23 in
3-6M: 23.5 to 26 in
6-9M: 26.5 to 27.5 in
12M: 28 to 29.5 in
18M: 30 to 31.5 in
24M: 32 to 33.5 in
2T: 32 to 33.5 in
3T: 34 to 37.5 in
4T: 38 to 41.5 in

Old Navy size to Wonder Nation size

Old Navy	Closest Wonder Nation	Match	Weight: Old Navy / Wonder Nation	Height: Old Navy / Wonder Nation
Up to 7 lb	Newborn	Partial	up to 6.6 lb / 5.5 to 7.5 lb	up to 21.7 in / 17.5 to 21 in
0-3M	0-3M	Partial	6.6 to 13.2 lb / 6.5 to 12 lb	21.7 to 24 in / 20.5 to 23 in
3-6M	3-6M	Close match	13.2 to 17.6 lb / 12.5 to 16 lb	24 to 26.4 in / 23.5 to 26 in
6-9M	6-9M	Partial	17.6 to 19.8 lb / 16.5 to 19 lb	26.4 to 29.1 in / 26.5 to 27.5 in
6-12M	12M	Partial	17.6 to 22 lb / 19.5 to 22 lb	26.4 to 29.1 in / 28 to 29.5 in
12-18M	18M	Partial	22 to 24.3 lb / 22.5 to 26 lb	29.1 to 31.5 in / 30 to 31.5 in
18-24M	24M	Partial	24.3 to 26.5 lb / 26.5 to 30 lb	31.5 to 33.9 in / 32 to 33.5 in
2T	24M	Partial	26.5 to 28.7 lb / 26.5 to 30 lb	33.9 to 36.2 in / 32 to 33.5 in
3T	3T	Partial	28.7 to 33.1 lb / 30.5 to 34 lb	36.2 to 39 in / 34 to 37.5 in
4T	4T	Partial	33.1 to 35.3 lb / 34.5 to 38 lb	39 to 42.1 in / 38 to 41.5 in

Wonder Nation size to Old Navy size

Wonder Nation	Closest Old Navy	Match	Weight: Wonder Nation / Old Navy	Height: Wonder Nation / Old Navy
Preemie	Up to 7 lb	No clean match	up to 5 lb / up to 6.6 lb	up to 17 in / up to 21.7 in
Newborn	Up to 7 lb	Partial	5.5 to 7.5 lb / up to 6.6 lb	17.5 to 21 in / up to 21.7 in
0-3M	0-3M	Partial	6.5 to 12 lb / 6.6 to 13.2 lb	20.5 to 23 in / 21.7 to 24 in
3-6M	3-6M	Close match	12.5 to 16 lb / 13.2 to 17.6 lb	23.5 to 26 in / 24 to 26.4 in
6-9M	6-9M	Partial	16.5 to 19 lb / 17.6 to 19.8 lb	26.5 to 27.5 in / 26.4 to 29.1 in
12M	6-12M	Partial	19.5 to 22 lb / 17.6 to 22 lb	28 to 29.5 in / 26.4 to 29.1 in
18M	12-18M	Partial	22.5 to 26 lb / 22 to 24.3 lb	30 to 31.5 in / 29.1 to 31.5 in
24M	18-24M	Partial	26.5 to 30 lb / 24.3 to 26.5 lb	32 to 33.5 in / 31.5 to 33.9 in
2T	18-24M	Partial	26.5 to 30 lb / 24.3 to 26.5 lb	32 to 33.5 in / 31.5 to 33.9 in
3T	3T	Partial	30.5 to 34 lb / 28.7 to 33.1 lb	34 to 37.5 in / 36.2 to 39 in
4T	4T	Partial	34.5 to 38 lb / 33.1 to 35.3 lb	38 to 41.5 in / 39 to 42.1 in

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Size

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Every Old Navy size in Wonder Nation

Close match

Old Navy 3-6M lines up closely with Wonder Nation 3-6M.

Weight (lb)

Old Navy 3-6M 13.2 to 17.6 lb

Wonder Nation 3-6M 12.5 to 16 lb

Wonder Nation 6-9M 16.5 to 19 lb

Height (in)

Old Navy 3-6M 24 to 26.4 in

Wonder Nation 3-6M 23.5 to 26 in

Wonder Nation 6-9M 26.5 to 27.5 in

The shaded column is the Old Navy range. Bars show what each brand publishes for the size.

Based on published size charts. Old Navy chart and Wonder Nation chart.

More comparisons

Charts retrieved October 4, 2026 (Old Navy) and October 4, 2026 (Wonder Nation). Sources are listed on each brand page. This site is not affiliated with either brand.