Find your child's Primary size
Enter your child's measurements and we'll show the right size — plus how long it will last.
Size recommendations are based on official brand size charts and are provided as a guide only. Fit may vary by item, style, and individual child. Outgrow is not responsible for sizing decisions made based on these recommendations.
Does Primary Run Small, Large, or True to Size?
Primary runs slightly large — intentionally. The brand's design philosophy is generous, inclusive fit. Each size covers a wider height and weight range than typical US kids' brands, which means the same item can fit a lean 6-year-old and a sturdier 5-year-old comfortably. This is by design: Primary makes gender-neutral basics meant to be passed between kids and worn across body types.
- No “T” suffix — Primary uses 2, 3, 4, 5 instead of 2T, 3T, 4T, 5T. These are true to equivalent T-sizes from other brands. If your child wears 3T in Carter's, they wear a 3 in Primary.
- Wide ranges per size — Primary's size ranges cover more height and weight than most US brands. A size 6 at Primary fits kids that Carter's would split across a 5 and a 6. This isn't a quality control issue; it's the brand's philosophy.
- Gender-neutral throughout — there are no separate boys' and girls' size charts. One chart, one cut, every kid. The fit is relaxed enough to work across body types.
- Sizes skip 9, 11, and 13 — after size 8, Primary jumps to 10, 12, 14. This follows a standard US big-kids convention but trips up parents who expect consecutive sizes.
- Pre-washed cotton, minimal shrinkage — Primary uses GOTS-certified organic cotton, and items are pre-washed before shipping. What you receive is close to the final size. Wash in cold, dry on low as a precaution.
- US and Canada only — Primary ships to the US and Canada. European customers can't order directly. If you're comparing Primary sizing to European brands, note that Primary uses US age-based sizing, not European height-in-cm sizing.
Primary Baby Size Chart (Newborn–24M)
Primary's baby range covers newborn through 24 months. Like most US baby brands, sizes here are primarily age-based, with height and weight ranges as guides.
| Primary Size | Age (approx.) | Height | Height (cm) | Weight |
|---|---|---|---|---|
| Newborn (NB) | 0–1 month | Up to 21" | Up to 53 cm | Up to 8 lbs / 3.6 kg |
| 0–3M | 0–3 months | 21–24" | 53–61 cm | 8–12 lbs / 3.6–5.4 kg |
| 3–6M | 3–6 months | 24–26" | 61–66 cm | 12–16 lbs / 5.4–7.3 kg |
| 6–12M | 6–12 months | 26–29" | 66–74 cm | 16–22 lbs / 7.3–10 kg |
| 12–18M | 12–18 months | 29–31" | 74–79 cm | 22–26 lbs / 10–11.8 kg |
| 18–24M | 18–24 months | 31–33" | 79–84 cm | 26–30 lbs / 11.8–13.6 kg |
Primary Kids Size Chart (2–14)
This is where Primary's sizing philosophy makes the most difference. The ranges are wide, the fit is relaxed, and the gender-neutral cut means one chart covers every child.
| Primary Size | Age (approx.) | Height | Height (cm) | Weight |
|---|---|---|---|---|
| 2 | 2 years | 33–36" | 84–91 cm | 26–32 lbs / 11.8–14.5 kg |
| 3 | 3 years | 36–39" | 91–99 cm | 30–36 lbs / 13.6–16.3 kg |
| 4 | 4 years | 39–43" | 99–109 cm | 36–43 lbs / 16.3–19.5 kg |
| 5 | 5 years | 43–46" | 109–117 cm | 40–50 lbs / 18.1–22.7 kg |
| 6 | 5–6 years | 45–48" | 114–122 cm | 46–57 lbs / 20.9–25.9 kg |
| 7 | 6–7 years | 47–51" | 119–130 cm | 52–65 lbs / 23.6–29.5 kg |
| 8 | 7–8 years | 50–54" | 127–137 cm | 58–75 lbs / 26.3–34 kg |
| 10 | 9–10 years | 54–57" | 137–145 cm | 70–87 lbs / 31.8–39.5 kg |
| 12 | 11–12 years | 57–60" | 145–152 cm | 80–100 lbs / 36.3–45.4 kg |
| 14 | 12–13 years | 59–63" | 150–160 cm | 90–115 lbs / 40.8–52.2 kg |
The No-“T” Question: Does It Matter?
At most US brands, there's a meaningful distinction between, say, a 4T and a size 4. The “T” stands for toddler — 4T is cut with more room in the diaper area and a slightly rounder, shorter body. Size 4 assumes the child is past the diaper stage and has slimmer, longer proportions.
Primary doesn't make this distinction. Their sizes 2 through 5 simply use the number, and the cut is a relaxed gender-neutral fit that works for most toddler body types without a diaper-specific cut. In practice:
- If your child wears 2T in Carter's or Gap → order size 2 in Primary
- If your child wears 4T → order size 4 in Primary
- If your child is right between sizes, Primary's wider ranges mean the larger size usually works fine
The absence of T-sizing is slightly confusing at first but ultimately simpler: one less thing to think about.
How Primary Compares to Other Brands
Primary's intentionally wide ranges and relaxed fit mean it sits differently in the comparison landscape.
| Brand | vs. Primary |
|---|---|
| Carter's | Carter's runs slightly smaller and has more fitted cuts, especially in toddler basics. A Carter's 4T is narrower through the body than a Primary size 4 |
| Gap Kids | Gap runs similar to Primary at the younger sizes; both are more generous than Carter's. Gap has more fitted options; Primary deliberately avoids fitted cuts |
| Old Navy | Old Navy runs small, especially for girls. Primary is more generous. A child who sizes up in Old Navy will likely fit true to size in Primary |
| H&M | H&M uses European height-based sizing and runs narrow. Primary is significantly more generous in the body at equivalent age labels |
| Cat & Jack (Target) | Similar true-to-size feel, but Cat & Jack has gender-specific cuts and slimmer fits available. Primary is the more relaxed of the two |
| Hanna Andersson | Closest comparable in fit philosophy — both run relaxed and prioritise comfort over fitted cuts. Hanna uses European cm sizing; Primary uses US age sizing |
| The Children's Place | TCP runs slimmer than Primary. Children who wear Primary and try TCP often need to size up in TCP |
Why Primary Sizing Feels Different to New Buyers
Primary was founded in 2015 by two former Diapers.com executives who built the brand on a specific philosophy: simple, timeless basics that let kids be kids. Every sizing and design decision flows from this:
- Wide ranges mean more kids can wear the same item, making hand-me-downs work better. A Primary size 6 passed from an older child to a younger sibling has a better chance of actually fitting than a more fitted brand.
- No garment measurements published because the brand believes height and weight are what parents actually know and use. This is unusual — almost every other brand publishes chest and waist measurements — and it does mean the charts are less useful for borderline cases. If your child falls squarely between sizes and you want more precision, call Primary's customer service (1-844-435-5675, weekdays 9am–6pm ET); they'll guide you based on your child's specific measurements.
- Gender-neutral, one-chart sizing means Primary doesn't produce a separate boys' fit with a slimmer waist or a girls' fit with a wider hip. The cut is designed to work across body types, which is part of why the fit runs relaxed.
- Styles that don't change is the final piece of the cult-following puzzle. Primary's Long Sleeve Tee looks the same today as it did five years ago. If a size 4 worked brilliantly, you can order the same item in size 8 four years later with full confidence it'll look the same. Most fast-fashion brands can't say this.
How Long Will Primary Clothes Last?
Because Primary's wide ranges are intentional, items genuinely tend to have more wearable life than the size chart implies. A child who is on the smaller end of a size range has more room to grow into; a child at the top end will get a few good months before outgrowing.
| Primary Size | Average Wear Time |
|---|---|
| NB–0–3M | 2–3 months |
| 3–6M | 2–4 months |
| 6–12M | 4–6 months |
| 12–18M | 4–6 months |
| 18–24M | 4–6 months |
| 2–3 | 6–10 months |
| 4–5 | 8–12 months |
| 6–7 | 10–14 months |
| 8–10 | 12–16 months |
| 12–14 | 14–18 months |
Frequently Asked Questions
Does Primary run small or large?
Primary runs slightly large and relaxed by design. If your child is between sizes, size down rather than up — the fit is generous enough that the smaller size will likely work, and will last longer as your child grows into it.
Is a Primary size 4 the same as a 4T?
For most children, yes. Primary doesn’t use "T" sizing. Their size 4 covers the same general height and weight range as a 4T at Carter’s or Gap, but without a diaper-specific cut. If your child is comfortably in 4T elsewhere, order size 4 at Primary.
Does Primary have boys' and girls' sizing?
No. Primary is gender-neutral throughout — no separate boys’ or girls’ charts, no different cuts by gender. One chart covers all kids. For items that need more structural support (like swimwear), the cut is adjusted for coverage, but sizes remain the same.
Can I order Primary if I'm in the UK or Europe?
Primary ships to the US and Canada only. UK and European customers can’t order directly. If you see Primary items secondhand or through a reseller, use the height/weight chart above to find your child’s size — Primary uses US age-based sizing, not European cm sizing, so direct conversion by age is close but not precise.
What happened to Primary size 9, 11, or 13?
Primary doesn’t offer these sizes. After size 8, the range goes to 10, 12, and 14 — this is standard US big-kids sizing and the same convention used by Carter’s, Gap, and Old Navy. If your child measures between size 8 and 10, order size 10.
Does Primary clothing shrink?
Primary pre-washes their items before shipping, so the size you receive is close to the true washed size. Washing in cold water and drying on low minimises any further change. As with all cotton, some minor softening of the fabric is normal over time, but significant shrinkage is uncommon.
How does Primary compare to H&M Kids sizing?
H&M uses European height-based sizing in centimetres (98, 104, 110...) and runs narrow. Primary uses US age-based sizing and runs relaxed and wide. At equivalent ages, Primary typically fits larger and more generously than H&M. If your child wears H&M 110 (roughly 4–5 years), they’re likely a size 5 in Primary.
Also shopping at Carter's, Gap Kids, Old Navy, H&M, Cat & Jack or The Children's Place?