Brand vs brand

Old Navy vs Primary sizes

Of Old Navy's 10 baby and toddler sizes, 2 line up closely with a Primary size, 7 are partial matches, and 1 has no clean match. Both charts list weight and height, so the comparison uses both.

Closest pairs: Old Navy 6-12M = Primary 9-12M, Old Navy 12-18M = Primary 12-18M.

Watch the labels: Old Navy 0-3M is closer to Primary 0-3M than to Primary's own 0-3M; Old Navy 3-6M is closer to Primary 6-9M than to Primary's own 3-6M; Old Navy 6-9M is closer to Primary 9-12M than to Primary's own 6-9M.

Old Navy True to sizePrimary True to size

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

Primary

Newborn: 5.1 to 9 lb
0-3M: 9 to 11.9 lb
3-6M: 11.9 to 15 lb
6-9M: 15 to 18.1 lb
6-12M: 15 to 22 lb
9-12M: 18.1 to 22 lb
12-18M: 22 to 26.9 lb
18-24M: 26.9 to 30 lb
2: 30 to 33.1 lb
3: 33.1 to 35.9 lb
4: 35.9 to 39.9 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

Primary

Newborn: up to 18.1 in
0-3M: 18.1 to 22.8 in
3-6M: 22.8 to 25.2 in
6-9M: 25.2 to 27.2 in
6-12M: 25.2 to 29.1 in
9-12M: 27.2 to 29.1 in
12-18M: 29.1 to 31.1 in
18-24M: 31.1 to 33.1 in
2: 33.1 to 35 in
3: 35 to 38.2 in
4: 38.2 to 40.9 in

Old Navy size to Primary size

Old Navy	Closest Primary	Match	Weight: Old Navy / Primary	Height: Old Navy / Primary
Up to 7 lb	0-3M	No clean match	up to 6.6 lb / 9 to 11.9 lb	up to 21.7 in / 18.1 to 22.8 in
0-3M	0-3M	Partial	6.6 to 13.2 lb / 9 to 11.9 lb	21.7 to 24 in / 18.1 to 22.8 in
3-6M	6-9M	Partial	13.2 to 17.6 lb / 15 to 18.1 lb	24 to 26.4 in / 25.2 to 27.2 in
6-9M	9-12M	Partial	17.6 to 19.8 lb / 18.1 to 22 lb	26.4 to 29.1 in / 27.2 to 29.1 in
6-12M	9-12M	Close match	17.6 to 22 lb / 18.1 to 22 lb	26.4 to 29.1 in / 27.2 to 29.1 in
12-18M	12-18M	Close match	22 to 24.3 lb / 22 to 26.9 lb	29.1 to 31.5 in / 29.1 to 31.1 in
18-24M	18-24M	Partial	24.3 to 26.5 lb / 26.9 to 30 lb	31.5 to 33.9 in / 31.1 to 33.1 in
2T	18-24M	Partial	26.5 to 28.7 lb / 26.9 to 30 lb	33.9 to 36.2 in / 31.1 to 33.1 in
3T	2	Partial	28.7 to 33.1 lb / 30 to 33.1 lb	36.2 to 39 in / 33.1 to 35 in
4T	3	Partial	33.1 to 35.3 lb / 33.1 to 35.9 lb	39 to 42.1 in / 35 to 38.2 in

Primary size to Old Navy size

Primary	Closest Old Navy	Match	Weight: Primary / Old Navy	Height: Primary / Old Navy
Newborn	Up to 7 lb	No clean match	5.1 to 9 lb / up to 6.6 lb	up to 18.1 in / up to 21.7 in
0-3M	0-3M	Partial	9 to 11.9 lb / 6.6 to 13.2 lb	18.1 to 22.8 in / 21.7 to 24 in
3-6M	3-6M	Partial	11.9 to 15 lb / 13.2 to 17.6 lb	22.8 to 25.2 in / 24 to 26.4 in
6-9M	3-6M	Partial	15 to 18.1 lb / 13.2 to 17.6 lb	25.2 to 27.2 in / 24 to 26.4 in
6-12M	6-12M	Close match	15 to 22 lb / 17.6 to 22 lb	25.2 to 29.1 in / 26.4 to 29.1 in
9-12M	6-12M	Close match	18.1 to 22 lb / 17.6 to 22 lb	27.2 to 29.1 in / 26.4 to 29.1 in
12-18M	12-18M	Close match	22 to 26.9 lb / 22 to 24.3 lb	29.1 to 31.1 in / 29.1 to 31.5 in
18-24M	18-24M	Partial	26.9 to 30 lb / 24.3 to 26.5 lb	31.1 to 33.1 in / 31.5 to 33.9 in
2	3T	Partial	30 to 33.1 lb / 28.7 to 33.1 lb	33.1 to 35 in / 36.2 to 39 in
3	4T	Partial	33.1 to 35.9 lb / 33.1 to 35.3 lb	35 to 38.2 in / 39 to 42.1 in
4	4T	Partial	35.9 to 39.9 lb / 33.1 to 35.3 lb	38.2 to 40.9 in / 39 to 42.1 in

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Size

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Every Old Navy size in Primary

Close match

Old Navy 6-12M lines up closely with Primary 9-12M.

Weight (lb)

Old Navy 6-12M 17.6 to 22 lb

Primary 6-9M 15 to 18.1 lb

Primary 6-12M 15 to 22 lb

Primary 9-12M 18.1 to 22 lb

Height (in)

Old Navy 6-12M 26.4 to 29.1 in

Primary 6-9M 25.2 to 27.2 in

Primary 6-12M 25.2 to 29.1 in

Primary 9-12M 27.2 to 29.1 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 Primary chart.

More comparisons

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