Brand vs brand

Little Sleepies vs Primary sizes

Of Little Sleepies' 10 baby and toddler sizes, 0 line up closely with a Primary size, 10 are partial matches, and 0 have no clean match. Both charts list weight and height, so the comparison uses both.

Watch the labels: Little Sleepies Newborn is closer to Primary Newborn than to Primary's own Newborn; Little Sleepies 0-3M is closer to Primary 0-3M than to Primary's own 0-3M; Little Sleepies 3-6M is closer to Primary 3-6M than to Primary's own 3-6M.

Little Sleepies 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)

Little Sleepies

Preemie: up to 5 lb
Newborn: 5 to 8 lb
0-3M: 8 to 12 lb
3-6M: 12 to 17 lb
6-12M: 17 to 23 lb
12-18M: 23 to 26 lb
18-24M: 26 to 30 lb
2T: 29 to 31 lb
3T: 31 to 35 lb
4T: 35 to 39 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)

Little Sleepies

Preemie: up to 18 in
Newborn: 18 to 21 in
0-3M: 21 to 23 in
3-6M: 23 to 27 in
6-12M: 27 to 31 in
12-18M: 31 to 33 in
18-24M: 33 to 34.5 in
2T: 33 to 36 in
3T: 36 to 39 in
4T: 39 to 42 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

Little Sleepies size to Primary size

Little Sleepies	Closest Primary	Match	Weight: Little Sleepies / Primary	Height: Little Sleepies / Primary
Preemie	Newborn	Partial	up to 5 lb / 5.1 to 9 lb	up to 18 in / up to 18.1 in
Newborn	Newborn	Partial	5 to 8 lb / 5.1 to 9 lb	18 to 21 in / up to 18.1 in
0-3M	0-3M	Partial	8 to 12 lb / 9 to 11.9 lb	21 to 23 in / 18.1 to 22.8 in
3-6M	3-6M	Partial	12 to 17 lb / 11.9 to 15 lb	23 to 27 in / 22.8 to 25.2 in
6-12M	9-12M	Partial	17 to 23 lb / 18.1 to 22 lb	27 to 31 in / 27.2 to 29.1 in
12-18M	18-24M	Partial	23 to 26 lb / 26.9 to 30 lb	31 to 33 in / 31.1 to 33.1 in
18-24M	18-24M	Partial	26 to 30 lb / 26.9 to 30 lb	33 to 34.5 in / 31.1 to 33.1 in
2T	2	Partial	29 to 31 lb / 30 to 33.1 lb	33 to 36 in / 33.1 to 35 in
3T	3	Partial	31 to 35 lb / 33.1 to 35.9 lb	36 to 39 in / 35 to 38.2 in
4T	4	Partial	35 to 39 lb / 35.9 to 39.9 lb	39 to 42 in / 38.2 to 40.9 in

Primary size to Little Sleepies size

Primary	Closest Little Sleepies	Match	Weight: Primary / Little Sleepies	Height: Primary / Little Sleepies
Newborn	Preemie	Partial	5.1 to 9 lb / up to 5 lb	up to 18.1 in / up to 18 in
0-3M	0-3M	Partial	9 to 11.9 lb / 8 to 12 lb	18.1 to 22.8 in / 21 to 23 in
3-6M	3-6M	Partial	11.9 to 15 lb / 12 to 17 lb	22.8 to 25.2 in / 23 to 27 in
6-9M	3-6M	Partial	15 to 18.1 lb / 12 to 17 lb	25.2 to 27.2 in / 23 to 27 in
6-12M	6-12M	Partial	15 to 22 lb / 17 to 23 lb	25.2 to 29.1 in / 27 to 31 in
9-12M	6-12M	Partial	18.1 to 22 lb / 17 to 23 lb	27.2 to 29.1 in / 27 to 31 in
12-18M	12-18M	Partial	22 to 26.9 lb / 23 to 26 lb	29.1 to 31.1 in / 31 to 33 in
18-24M	12-18M	Partial	26.9 to 30 lb / 23 to 26 lb	31.1 to 33.1 in / 31 to 33 in
2	2T	Partial	30 to 33.1 lb / 29 to 31 lb	33.1 to 35 in / 33 to 36 in
3	3T	Partial	33.1 to 35.9 lb / 31 to 35 lb	35 to 38.2 in / 36 to 39 in
4	4T	Partial	35.9 to 39.9 lb / 35 to 39 lb	38.2 to 40.9 in / 39 to 42 in

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Size

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Every Little Sleepies size in Primary

Partial match

Little Sleepies Preemie is closest to Primary Newborn, but it is not a clean match.

Weight (lb)

Little Sleepies Preemie up to 5 lb

Primary Newborn 5.1 to 9 lb

Height (in)

Little Sleepies Preemie up to 18 in

Primary Newborn up to 18.1 in

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

Based on published size charts. Little Sleepies chart and Primary chart.

More comparisons

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