Brand vs brand

Nike vs Primary sizes

Of Nike's 10 baby and toddler sizes, 3 line up closely with a Primary size, 5 are partial matches, and 2 have no clean match. Both charts list weight and height, so the comparison uses both.

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

Watch the labels: Nike 2T is closer to Primary 18-24M than to Primary's own 2T; Nike 3T is closer to Primary 2 than to Primary's own 3T.

Nike Runs largePrimary 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)

Nike

Newborn/0-3M: 6 to 9.5 lb
3M: 9.9 to 14.6 lb
6M: 15 to 17.9 lb
9M: 18.3 to 22 lb
12M: 22.5 to 24.9 lb
18M: 25.6 to 28 lb
24M: 28.4 to 30 lb
2T: 28.4 to 30 lb
3T: 30.4 to 33.1 lb
4T: 34 to 37.9 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)

Nike

Newborn/0-3M: 19.7 to 22 in
3M: 22 to 24.4 in
6M: 24.4 to 26.8 in
9M: 26.8 to 29.1 in
12M: 29.1 to 31.5 in
18M: 31.5 to 33.9 in
24M: 33.9 to 36.2 in
2T: 33.9 to 36.2 in
3T: 36.2 to 38.6 in
4T: 38.6 to 40.9 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

Nike size to Primary size

Nike	Closest Primary	Match	Weight: Nike / Primary	Height: Nike / Primary
Newborn/0-3M	Newborn	Partial	6 to 9.5 lb / 5.1 to 9 lb	19.7 to 22 in / up to 18.1 in
3M	3-6M	Partial	9.9 to 14.6 lb / 11.9 to 15 lb	22 to 24.4 in / 22.8 to 25.2 in
6M	6-9M	Close match	15 to 17.9 lb / 15 to 18.1 lb	24.4 to 26.8 in / 25.2 to 27.2 in
9M	9-12M	Close match	18.3 to 22 lb / 18.1 to 22 lb	26.8 to 29.1 in / 27.2 to 29.1 in
12M	12-18M	Close match	22.5 to 24.9 lb / 22 to 26.9 lb	29.1 to 31.5 in / 29.1 to 31.1 in
18M	18-24M	Partial	25.6 to 28 lb / 26.9 to 30 lb	31.5 to 33.9 in / 31.1 to 33.1 in
24M	18-24M	No clean match	28.4 to 30 lb / 26.9 to 30 lb	33.9 to 36.2 in / 31.1 to 33.1 in
2T	18-24M	No clean match	28.4 to 30 lb / 26.9 to 30 lb	33.9 to 36.2 in / 31.1 to 33.1 in
3T	2	Partial	30.4 to 33.1 lb / 30 to 33.1 lb	36.2 to 38.6 in / 33.1 to 35 in
4T	4	Partial	34 to 37.9 lb / 35.9 to 39.9 lb	38.6 to 40.9 in / 38.2 to 40.9 in

Primary size to Nike size

Primary	Closest Nike	Match	Weight: Primary / Nike	Height: Primary / Nike
Newborn	Newborn/0-3M	Partial	5.1 to 9 lb / 6 to 9.5 lb	up to 18.1 in / 19.7 to 22 in
0-3M	Newborn/0-3M	Partial	9 to 11.9 lb / 6 to 9.5 lb	18.1 to 22.8 in / 19.7 to 22 in
3-6M	3M	Partial	11.9 to 15 lb / 9.9 to 14.6 lb	22.8 to 25.2 in / 22 to 24.4 in
6-9M	6M	Close match	15 to 18.1 lb / 15 to 17.9 lb	25.2 to 27.2 in / 24.4 to 26.8 in
6-12M	9M	Partial	15 to 22 lb / 18.3 to 22 lb	25.2 to 29.1 in / 26.8 to 29.1 in
9-12M	9M	Close match	18.1 to 22 lb / 18.3 to 22 lb	27.2 to 29.1 in / 26.8 to 29.1 in
12-18M	12M	Close match	22 to 26.9 lb / 22.5 to 24.9 lb	29.1 to 31.1 in / 29.1 to 31.5 in
18-24M	18M	Partial	26.9 to 30 lb / 25.6 to 28 lb	31.1 to 33.1 in / 31.5 to 33.9 in
2	3T	Partial	30 to 33.1 lb / 30.4 to 33.1 lb	33.1 to 35 in / 36.2 to 38.6 in
3	3T	Partial	33.1 to 35.9 lb / 30.4 to 33.1 lb	35 to 38.2 in / 36.2 to 38.6 in
4	4T	Partial	35.9 to 39.9 lb / 34 to 37.9 lb	38.2 to 40.9 in / 38.6 to 40.9 in

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Size

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Every Nike size in Primary

Close match

Nike 6M lines up closely with Primary 6-9M.

Weight (lb)

Nike 6M 15 to 17.9 lb

Primary 3-6M 11.9 to 15 lb

Primary 6-9M 15 to 18.1 lb

Primary 6-12M 15 to 22 lb

Height (in)

Nike 6M 24.4 to 26.8 in

Primary 3-6M 22.8 to 25.2 in

Primary 6-9M 25.2 to 27.2 in

Primary 6-12M 25.2 to 29.1 in

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

Based on published size charts. Nike chart and Primary chart.

More comparisons

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