Old Navy is one of the most shopped kids' clothing brands in the US. It's also one of the most consistently described as generous — parents on every parenting forum say the same thing: Old Navy runs big, buy a size down. It's become received wisdom.
We compared Old Navy's verified size chart measurements against Carter's, H&M, Gap Kids and Cat & Jack at the same child heights — the brands most likely to be in the same wardrobe. What we found is that Old Navy's published waist and hip measurements are actually narrower than most of those brands at the equivalent height. Old Navy does not run big by the numbers.
The generous feeling probably comes from two things: Old Navy's relaxed, casual cut makes garments look roomy even when the measurements are average, and the wide T-size height brackets mean children often enter a size with plenty of length headroom. Neither of those things means the measurements are generous. This guide covers what the data actually shows — and the one genuine Old Navy sizing quirk that catches nearly every parent off guard.
Find your child's Old Navy 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 Old Navy Kids Run Big? What the Size Charts Show
We compared Old Navy's published waist and hip measurements against four brands that parents commonly shop alongside Old Navy — and at the kids size range, Old Navy's targets sit narrower than most of them. Carter's and H&M both have higher waist targets at the same height. Gap Kids is slightly lower than Old Navy in waist but its hip target is considerably higher. Of the five brands compared, only Cat & Jack targets a narrower waist than Old Navy.
This is the opposite of what most parents expect. The "runs generous" perception is real but the cause isn't the measurements — it's the style. Old Navy casual clothing has a relaxed, roomy cut through the body that reads as generous even when the size chart numbers are average or below average. And the T-size brackets cover a large height range, so children are often near the bottom of a bracket when they first go into a size, which means plenty of length room ahead of them. That's longevity, not generosity.
The 5T vs XS (5) Question: What Nobody Tells You
This is the most practically important thing to know about Old Navy sizing and it's almost never explained clearly. At around 107–114cm, Old Navy offers two completely different garments with almost identical height ranges: 5T and XS (5).
| Size | Height | Waist | Hip | Designed for |
|---|---|---|---|---|
| 5T | 107–114cm | 52–54cm | 58–60cm | Child still in diapers — extra room in seat |
| XS (5) | 106.7–114.3cm | 57.2cm | 61.6cm | Child out of diapers — standard kids cut |
The waist difference is 3–5cm between the two. If your child is potty trained, XS (5) is the right garment. If you accidentally pick up 5T — which is easy to do because they hang on the same rail and the labels look similar — the seat will be noticeably roomy. This is not Old Navy running big. This is two garments designed for two different children that happen to cover the same height range.
The same overlap exists at the next size up: 6T (114–119cm) and S (6) (114.3–121.9cm) cover nearly identical heights but again with different waist targets.
The Boys Gap at 119–122cm
Old Navy boys bottoms have a genuine hole in the size range. The 6T size ends at 119cm. The S (7) size starts at 122cm. No standard Old Navy boys bottom covers a boy at 120–121cm.
This gap does not exist in girls sizing. If your boy is in this range, the options are to size up to S (7) and expect some extra length, or check whether the 6T measurements still work — the waist of 54–56cm and hip of 60–64cm may fit well even if the length is short. Outgrow's size finder flags this gap automatically and suggests the best available option.
One Child, Five Brands — How Old Navy Compares
The same boy from our H&M comparison: 112cm tall, 19.5kg, 53.5cm waist, 58.5cm hip. Here is what each brand's size chart says about him.
| Brand | Size | Waist target | Wear time | Note |
|---|---|---|---|---|
| H&M | No match | 110: 56–58cm | 116: 58–59cm | — | Child's 53.5cm waist falls between brackets. Too slim for 116, too tall for 110. |
| Carter's | 5 | 55.5–58.5cm | ~3 months | Fits. Waist slightly loose but within tolerance. Weight ceiling approaching. |
| Old Navy | XS (5) | 57.2cm | ~5 months | Good fit. Child's waist 3.7cm below target — comfortable room to grow. Limited by height. |
| Gap Kids | XS (5 yrs) | 56cm waist, 65cm hip | ~4 months | Height fits. Hip 6.5cm below published target — will fit loosely through the seat. |
| Cat & Jack | No match | 52.7cm waist | — | Child's 53.5cm waist exceeds Cat & Jack's ceiling. Too broad for this size. |
Child profile: boy, 112cm / 44in, 19.5kg / 43lbs, 53.5cm waist, 58.5cm hip. Wear time based on Outgrow longevity data.
The Old Navy row shows the best result of any brand for this child — 5 months with comfortable room to grow in the waist. But it is important to note that Old Navy's 57.2cm waist target is higher than both Cat & Jack (52.7cm) and Carter's floor (55.5cm) at the same height. Old Navy is not the generous brand in this table. H&M's 116 bracket floor at 58cm and Gap's 56cm target are the references that bracket the child from above. Old Navy sits in the middle — which for this child happens to be the best fit.
For the full explanation of why the same child gets different results across these brands, see our cross-brand sizing research. See also our complete kids clothing size chart comparing 36+ brands side by side.
Old Navy Boys Tops Size Chart
Old Navy uses age text labels for baby, T-suffix for toddler, and dual alpha+number labels for kids — both the letter and number appear on the tag. Heights are the primary sizing guide from the kids range onward.
| Label | Height (cm) | Chest (cm) | Weight (kg) |
|---|---|---|---|
| Up to 7 lbs | 0–55 | 36–38 | 0–3 |
| 0–3M | 55–61 | 38–42 | 3–6 |
| 3–6M | 61–67 | 42–45 | 6–8 |
| 6–9M / 6–12M | 67–74 | 45–48 | 8–10 |
| 12–18M | 74–80 | 48–50 | 10–11 |
| 18–24M | 80–86 | 50–51 | 11–12 |
| 2T | 86–92 | 51–53 | 12–13 |
| 3T | 92–99 | 53–55 | 13–15 |
| 4T | 99–107 | 55–57 | 15–16 |
| 5T | 107–114 | 57–58 | 16–19 |
| XS (5) | 107–115 | 60 | — |
| 6T | 114–119 | 58–60 | 19–21 |
| S (6) | 115–122 | 63 | — |
| S (7) | 122–130 | 65 | — |
| M (8) | 130–138 | 68 | — |
| L (10) | 138–145 | 71 | — |
| L (12) | 145–153 | 74 | — |
| XL (14) | 153–161 | 77 | — |
| XL (16) | 161–166 | 81 | — |
| XXL (18) | 166–171 | 84 | — |
⚑ 6-9M and 6-12M are both valid labels with identical measurements. ⚑ 5T and XS (5) overlap in height — different waist targets for diaper vs non-diaper fit.
Old Navy Girls Tops Size Chart
| Label | Height (cm) | Chest (cm) | Weight (kg) |
|---|---|---|---|
| Up to 7 lbs | 0–55 | 36–38 | 0–3 |
| 0–3M | 55–61 | 38–42 | 3–6 |
| 3–6M | 61–67 | 42–45 | 6–8 |
| 6–9M / 6–12M | 67–74 | 45–48 | 8–10 |
| 12–18M | 74–80 | 48–50 | 10–11 |
| 18–24M | 80–86 | 50–51 | 11–12 |
| 2T | 86–92 | 51–53 | 12–13 |
| 3T | 92–99 | 53–55 | 13–15 |
| 4T | 99–107 | 55–57 | 15–16 |
| 5T | 107–114 | 57–58 | 16–19 |
| XS (5) | 107–115 | 61 | — |
| 6T | 114–119 | 58–60 | 19–21 |
| S (6) | 115–125 | 64 | — |
| S (7) | 125–135 | 67 | — |
| M (8) | 135–140 | 69 | — |
| L (10) | 140–145 | 73 | — |
| L (12) | 145–153 | 77 | — |
| XL (14) | 153–158 | 81 | — |
| XL (16) | 158–163 | 84 | — |
| XXL (18) | 158–163 | 87 | — |
Old Navy Boys Bottoms Size Chart
| Label | Height (cm) | Waist (cm) | Hip (cm) | Weight (kg) |
|---|---|---|---|---|
| Up to 7 lbs | 0–55 | 36–39 | 34–37 | 0–3 |
| 0–3M | 55–61 | 39–41 | 37–41 | 3–6 |
| 3–6M | 61–67 | 41–43 | 41–44 | 6–8 |
| 6–9M / 6–12M | 67–74 | 43–45 | 44–47 | 8–10 |
| 12–18M | 74–80 | 45–46 | 47–49 | 10–11 |
| 18–24M | 80–86 | 46–48 | 49–51 | 11–12 |
| 2T | 86–92 | 48–49 | 51–53 | 12–13 |
| 3T | 92–99 | 49–51 | 53–55 | 13–15 |
| 4T | 99–107 | 51–52 | 55–58 | 15–16 |
| 5T | 107–114 | 52–54 | 58–60 | 16–19 |
| XS (5) | 106.7–114.3 | 57.2 | 61.6 | — |
| 6T | 114–119 | 54–56 | 60–64 | 19–21 |
| S (6) | 114.3–121.9 | 58.4 | 64.8 | — |
| S (7) | 121.9–129.5 | 59.7 | 67.9 | — |
| M (8) | 129.5–137.2 | 61.0 | 71.1 | — |
| L (10) | 137.2–144.8 | 64.1 | 74.3 | — |
| L (12) | 144.8–152.4 | 67.3 | 77.5 | — |
| XL (14) | 152.4–160.0 | 71.1 | 81.3 | — |
| XL (16) | 160.0–165.1 | 74.9 | 85.1 | — |
| XXL (18) | 165.1–170.2 | 78.7 | 88.9 | — |
⚑ 5T and XS (5) overlap in height but have a 3–5cm waist difference. ⚑ Boys gap: 6T ends 119cm, S (7) starts 122cm — no coverage 119–122cm.
Boys Slim Fit
Old Navy Slim is meaningfully narrower than Regular — at XS (5) the Slim waist is 52.1cm versus 57.2cm Regular, a 5cm difference that matters for lean children.
| Label | Height (cm) | Waist (cm) | Hip (cm) |
|---|---|---|---|
| XS (5) Slim | 106.7–114.3 | 52.1 | 56.5 |
| S (6) Slim | 114.3–121.9 | 53.3 | 59.7 |
| S (7) Slim | 121.9–129.5 | 54.6 | 62.9 |
| M (8) Slim | 129.5–137.2 | 55.9 | 66.0 |
| L (10) Slim | 137.2–144.8 | 59.1 | 69.2 |
| L (12) Slim | 144.8–152.4 | 62.2 | 72.4 |
Old Navy Girls Bottoms Size Chart
| Label | Height (cm) | Waist (cm) | Hip (cm) | Weight (kg) |
|---|---|---|---|---|
| Up to 7 lbs | 0–55 | 36–39 | 34–37 | 0–3 |
| 0–3M | 55–61 | 39–41 | 37–41 | 3–6 |
| 3–6M | 61–67 | 41–43 | 41–44 | 6–8 |
| 6–9M / 6–12M | 67–74 | 43–45 | 44–47 | 8–10 |
| 12–18M | 74–80 | 45–46 | 47–49 | 10–11 |
| 18–24M | 80–86 | 46–48 | 49–51 | 11–12 |
| 2T | 86–92 | 48–49 | 51–53 | 12–13 |
| 3T | 92–99 | 49–51 | 53–55 | 13–15 |
| 4T | 99–107 | 51–52 | 55–58 | 15–16 |
| 5T | 107–114 | 52–54 | 58–60 | 16–19 |
| XS (5) | 107–115 | 56 | 61 | — |
| 6T | 114–119 | 54–56 | 60–64 | 19–21 |
| S (6) | 115–125 | 58 | 65 | — |
| S (7) | 125–135 | 59 | 69 | — |
| M (8) | 135–140 | 60 | 73 | — |
| L (10) | 140–145 | 63 | 77 | — |
| L (12) | 145–153 | 65 | 82 | — |
| XL (14) | 153–158 | 68 | 86 | — |
| XL (16) | 158–163 | 70 | 91 | — |
| XXL (18) | 158–163 | 73 | 95 | — |
Old Navy Kids Shoe Size Chart
Old Navy uses a three-tier system: Baby (age labels), Little Kid (letter group + number), and Big Kid (number + Y suffix). All genders share the same chart.
| Label | Group | Foot length (cm) |
|---|---|---|
| 0–3M / 1 | Baby | 9.2 |
| 3–6M / 2 | Baby | 10.0 |
| 6–12M / 3 | Baby | 11.0 |
| 12–18M / 4 | Baby | 11.7 |
| 18–24M / 5 | Baby | 12.7 |
| XS / 3 | Little Kid | 11.0 |
| XS / 4 | Little Kid | 11.7 |
| XS / 5 | Little Kid | 12.5 |
| XS / 6 | Little Kid | 13.5 |
| S / 7 | Little Kid | 14.3 |
| S / 8 | Little Kid | 15.1 |
| M / 9 | Little Kid | 15.9 |
| M / 10 | Little Kid | 16.7 |
| 7 | Big Kid | 14.3 |
| 8 | Big Kid | 15.1 |
| 9 | Big Kid | 15.9 |
| 10 | Big Kid | 16.8 |
| 11 | Big Kid | 17.6 |
| 12 | Big Kid | 18.4 |
| 13 | Big Kid | 19.4 |
| 1Y | Big Kid | 20.2 |
| 2Y | Big Kid | 21.0 |
| 3Y | Big Kid | 21.9 |
| 4Y | Big Kid | 22.7 |
| 5Y | Big Kid | 23.5 |
| 6Y | Big Kid | 24.4 |
Measure foot length heel to longest toe while standing. The M/10 Little Kid and Big Kid 10 differ by 0.1cm from different source fractions \u2014 both are correct.
Frequently Asked Questions
Does Old Navy kids run big?
No — Old Navy’s published waist and hip measurements are narrower than most comparable brands at the same height. The generous feeling comes from the relaxed, casual cut style and wide height brackets, not from the size chart numbers. Use your child’s height to find the right size and don’t size down.
What is the difference between Old Navy 5T and XS (5)?
Both cover roughly 107–114cm but they are completely different garments. 5T has a waist of 52–54cm with extra room in the seat for a child still in diapers. XS (5) has a waist target of 57.2cm for a child out of diapers. If your child is potty trained, XS (5) is the right choice. Accidentally buying 5T will give a noticeably roomy seat.
Is Old Navy sizing the same as Gap Kids?
Not exactly. Both are owned by Gap Inc. but the measurements differ. Old Navy XS (5) boys bottoms has a waist target of 57.2cm while Gap Kids XS targets 56cm for the upper sub-size at the same height. They are similar but not identical — it is worth checking each brand against your child’s measurements rather than assuming they’re interchangeable.
What is Old Navy Slim fit?
Old Navy Slim is meaningfully narrower than Regular — at XS (5) the Slim waist is 52.1cm versus 57.2cm Regular, a 5cm difference. Slim is available in boys sizes XS through L (12). If your child finds Regular trousers gaping at the waist despite the height fitting, Slim is worth trying rather than sizing down in the label.
Why does Old Navy school uniform sizing run differently?
Old Navy uniform pieces are cut to a more structured, less stretchy standard than casual clothing. Many parents find sizing up one works better for uniform tops and polos. Uniform bottoms with adjustable waistbands are more forgiving and usually match regular Old Navy sizing.
Is there a gap in Old Navy boys sizing at 119–122cm?
Yes — Old Navy boys bottoms have no standard size covering 119–122cm. The 6T ends at 119cm and S (7) starts at 122cm. This gap does not exist in girls sizing. If your boy is in this range, size up to S (7) or check whether 6T measurements still work for his waist and hip.