The short answer
PatPat does not run small in one direction across the catalogue. It depends on which chart you are reading, and the differences are in the labels rather than in the sewing.
| Range | How PatPat compares | What to do |
|---|---|---|
| Baby, Newborn to 18-24M | Within half an inch of the US standard, and slightly longer from 12M up | Order the size you normally order |
| Toddler 2T / 2Y | Cut for a child about 1.5 to 2 inches shorter | Go up one size at 2T |
| Kids US 6 to 9 | Cut for a child 1 to 3 inches shorter at the same number | Order by height, not by number |
| Kids US 10 and 12 | Back in line, and 12 runs slightly longer | Order the size you normally order |
| Women's letters in family matching | About one letter smaller than a typical US adult chart | Order by chest measurement, one letter up |
| Snug-fit cotton and bamboo sleepwear | Measures correct, wears tight by law | Order true to size, do not size up |
Everything below is checkable. Every PatPat figure comes from the PatPat size chart, and every comparison figure comes from the published Carter's size chart, read on 15 September 2026. Carter's is used as the comparison because it is the chart most American parents already have a garment from, not because it is a standard. As the next section explains, there is no standard.
Why "runs small" is usually a label problem
When a parent says a brand runs small, they almost never mean the garment was sewn badly. They mean it was smaller than the last one they bought with the same word on the tag. That is a comparison between two charts, and in American children's clothing the two charts have nothing holding them together.
There is no government rule that says what 2T means. The Commerce Department stopped maintaining apparel sizing standards decades ago, and the National Institute of Standards and Technology now states plainly that it is no longer involved in any activities related to apparel-size standards. What replaced it was voluntary: ASTM published body measurement tables that brands could draft against if they chose. The table covering sizes 2 to 6X, ASTM D5826, was withdrawn in 2009 and never replaced for that range.
So a size label in the United States is a claim made by one brand about its own patterns. Two brands can both be honest and still cut a 2T two inches apart. That is the whole mechanism behind every "runs small" review, and it is why the useful question is not whether a brand runs small but where, and by how much. Why a gap of that size persists even inside a single brand, once manufacturing tolerance and shrinkage are added, is worked through in why "true to size" means nothing in children's clothing.
Baby sizes: almost identical, and slightly longer
This is the range people worry about most and the range where the two charts agree most closely.
| Label | PatPat height | Carter's height | PatPat weight | Carter's weight |
|---|---|---|---|---|
| Newborn | 18 to 22 in | 18 to 21.5 in | 6 to 9 lb | 6 to 9 lb |
| 0-3M / 3M | 22 to 24 in | 21.5 to 24 in | 9 to 13 lb | 9 to 12.5 lb |
| 3-6M / 6M | 24 to 27 in | 24 to 27 in | 13 to 17 lb | 12.5 to 17 lb |
| 6-9M / 9M | 27 to 29 in | 27 to 28.5 in | 17 to 21 lb | 17 to 21 lb |
| 9-12M / 12M | 29 to 31 in | 28.5 to 30 in | 21 to 25 lb | 21 to 25 lb |
| 12-18M / 18M | 31 to 33 in | 30 to 32 in | 25 to 28 lb | 25 to 28 lb |
| 18-24M / 24M | 33 to 35 in | 32 to 34 in | 28 to 30 lb | 28 to 30 lb |
The weight bands are the same to within half a pound at every step. On height, PatPat's bands sit half an inch to a full inch higher from 12M upward, which means a PatPat 18M is drafted for a slightly taller baby than an 18M from Carter's.
Read that carefully, because it runs against the reviews. In the baby range PatPat is drafted marginally larger, not smaller. A baby who has just outgrown one brand's 12M will usually still fit PatPat's 9-12M. Reviews describing PatPat baby clothes as roomy are consistent with the charts. Reviews describing them as small are usually describing a different range, most often the toddler sizes that come next.
One more thing worth knowing about this range: on PatPat's chart, Newborn is drafted to height and weight alone, and the chest, waist and hip cells are genuinely blank rather than estimated. That is unusual and it is deliberate. It also means that for a newborn, weight is the only figure that matters. Order to it.
Toddler: 2T is the one real gap
If there is a single place where PatPat runs small against the chart most American parents already own, it is here.
| Label | PatPat height | Carter's height |
|---|---|---|
| 2T / 2Y | 33 to 35 in | 35 to 36.5 in |
| 3T / 3Y | 35 to 39 in | 36.5 to 39 in |
| 4T / 3-4Y | 39 to 41 in | 39 to 41.5 in |
| 5T / 4-5Y | 41 to 44 in | 41.5 to 44 in |
At 2T the two charts barely overlap. PatPat's 2T is cut for a 33 to 35 inch child. Carter's 2T starts where PatPat's ends. A child at 35.5 inches is a comfortable Carter's 2T and is already out of PatPat's 2T.
There is a structural reason. On PatPat's chart, 18-24M and 2Y are the same draft, both 83.8 to 88.9 cm. Carter's treats 24M and 2T as two separate steps, with 24M at 32 to 34 inches and 2T starting at 35. So PatPat's 2T is, in effect, positioned where another brand's 24M sits. If a parent replaces an outgrown Carter's 24M with a PatPat 2T, they have bought the same size again.
The practical rule: at 2T, order one size up. From 3T onward the two charts run within half an inch of each other and the ordinary approach works again.
Kids numbers: the series has more steps
This is the second place the charts separate, and the reason is arithmetic rather than fit philosophy.
PatPat's kids range is built on a year-by-year age series and every year gets a number, so the run goes 6, 7, 8, 9, 10, 11, 12. Carter's kids numbers go 6, 7, 8, 10, 12, skipping the odd numbers above 8. Same digits, different number of steps between them, so the digits stop lining up.
| US number | PatPat height | Carter's height |
|---|---|---|
| 6 | 44 to 46 in | 45 to 48 in |
| 7 | 46 to 48 in | 48 to 51.5 in |
| 8 | 48 to 51 in | 51.5 to 53.5 in |
| 9 | 51 to 53 in | not offered |
| 10 | 53 to 55 in | 53.5 to 56 in |
| 11 | 55 to 57 in | not offered |
| 12 | 57 to 60 in | 56 to 58 in |
From 6 through 9 a PatPat number covers a shorter child than the same digit elsewhere, by one to three inches. The gap is widest at 7 and 8. A child in a Carter's 8 at 52 inches is a PatPat 9, not a PatPat 8.
Then it resolves. Because Carter's skips 9, the two charts meet again at 10, and by 12 PatPat runs two inches longer at the top.
The reason this range generates the most confused reviews is that the same child can honestly report running small one year and running true the next. Both are correct. Ignore the number and read the height column. PatPat's height conversion table lists every centimetre step against its own ranges for exactly this reason.
Women's sizes in family matching: read the chest, not the letter
Family matching is the line where an adult and a child buy from the same product page, and it is where adult sizing complaints concentrate.
| Letter | PatPat chest | Carter's women's chest |
|---|---|---|
| XS | 31.5 to 33 in | 33 to 34 in |
| S | 33.5 to 35 in | 35 to 36 in |
| M | 35.5 to 37.5 in | 37 to 38.5 in |
| L | 38 to 40 in | 40 to 41.5 in |
| XL | 40.5 to 43 in | 43.5 in |
| XXL | 43.5 to 46 in | 45.5 in |
The pattern is consistent all the way down: a PatPat letter is drafted for a chest about one and a half to two inches smaller than the same letter on a typical US adult chart. In practice that is roughly one letter.
So a shopper who wears M elsewhere is usually an L at PatPat, and a shopper who wears L is usually an XL. Ordering the familiar letter produces exactly the experience described in reviews as arriving a size too small. The garment is not mis-sewn. The letter means something different.
There is a second trap in the same line. PatPat runs two separate adult systems: a standard chart from XS to XXXL, and a plus-size chart from 0XL to 4XL against US 14W to 22W, which is a fuller cut rather than a scaled-up one. A plus-size 2XL and a standard XXL are different garments. If the plus size range is the right one, match on chest and hip and let the letters go.
Why snug-fit sleepwear measures correct and still feels tight
Some of the strongest "runs small" reactions come from pajamas, and this one is not a charting question at all. It is a legal requirement, and it applies to every brand selling children's sleepwear in the United States.
Children's sleepwear in sizes 0 through 14 has to satisfy the flammability standards at 16 CFR parts 1615 and 1616. There are two routes. A garment can pass a flame test, which in practice means flame-resistant fibres or a chemical treatment. Or it can qualify as a tight-fitting garment and be excepted from that testing.
The choice of fibre decides the route. The Consumer Product Safety Commission states that sleepwear made from certain untreated fibres typically fails that testing, and names 100% cotton, 100% silk, 100% rayon and 100% modal. Bamboo viscose is a rayon. So untreated cotton and bamboo sleepwear reaches the US market almost exclusively through the tight-fitting exception, and that exception is dimensional: 16 CFR 1615.1(o) and 1616.2(m) set maximum chest, waist, seat, upper arm, thigh, wrist and ankle measurements for every size, measured flat and doubled.
That is the whole explanation. A bamboo sleeper is capped by regulation at a maximum dimension and is designed to sit close to the body. It is meant to feel snug. The snugness is the safety mechanism, because loose fabric and air are what let a flame travel.
Which makes the most common piece of internet sizing advice wrong in this one category. Do not size up in untreated cotton or bamboo sleepwear. A garment loose on a child is no longer performing the function that let it be sold without flame-resistant treatment, and the hang tag on the garment says so. Size up in daywear if you want a second season out of it. In sleepwear, order the size that fits now.
Where PatPat's sizing genuinely causes trouble
Four things on PatPat's own charts make ordering harder than it needs to be. They are worth naming rather than leaving for a review to find.
Seven naming systems, sometimes inside one order. PatPat labels by month, by age, by US toddler number, by US kids number, by adult letter, by a separate plus-size letter, and by dog neck size. A matching set can put three or four of those on a single product page. Everything on the page is drafted from the same pattern data, but a shopper is still asked to switch systems mid-order.
2T and 2Y are the same garment. Identical draft, 83.8 to 88.9 cm, two labels. Which one appears depends on the product line rather than on the fit. That is not obvious from a product page, and it is the root of the 2T gap described above.
Youth letters look like adult letters. A small number of kids products use XS(5-6Y) through XL(13-14Y). An M(9-10Y) is a kids garment for a 53 to 55 inch child and is nowhere near an adult M. The age is printed in the label precisely because the letter alone misleads.
The end sizes are thin. Counted from live stock on 4 September 2026, women's XL appears on 417 products and women's 4XL on 25. Men's 4XL appears on five. Newborn appears on 61. The middle of every run is deep and the ends are not, which is ordinary in apparel but changes the order you should shop in. And PatPat drafts a 13-14Y that no product currently carries under that label. It is sold as XL(13-14Y) instead, cut to the same measurements.
None of this is a fit defect. All of it is a labelling burden that currently sits on the shopper.
What this comparison cannot tell you
This is a comparison of published patterns, not of finished garments. It shows how each brand drafts a size. It does not account for how a particular style was cut, how much ease the pattern carries, how a woven behaves against a knit at the same chest measurement, or how much a fabric moves after washing.
Those are separate questions with separate answers, and the honest position is that a chart comparison cannot settle them. What it can settle is the question most shoppers are actually asking, which is whether the number on the tag means what they think it means. On that, the charts are unambiguous.
What to do when a garment arrives and does not fit
The comparison above is for before ordering. When something has already arrived wrong, the useful question is which of three things happened, because the fix differs.
- It is the wrong size for the child. Measure the child and the garment flat, and compare both against the chart. If the chart was right and the ordered size was not, exchange it — and note the correct size against the measurement for next time.
- It is the right size and the wrong category. A snug-fit sleeper, a swimsuit and a legging are all supposed to be closer to the body than a t-shirt. If it fits and merely feels tighter than expected, that is usually the category rather than the size.
- It does not match its own chart. Measure the garment flat against the published figures. A genuine discrepancy is a manufacturing issue and worth reporting rather than absorbing, because it is the only one of the three that tells us something we can fix.
Before washing anything, try it on. Retailers accept unworn, unwashed returns and generally do not accept washed ones, and that single ordering of steps preserves every option. Everything should still be washed before it is actually worn, for the finishing-residue reason set out in how to wash baby clothes.
How to measure a child, so the chart is actually usable
Every recommendation in this article assumes you have a measurement to compare against the chart. Most people do not, which is why the label remains the default even though it is the least reliable number available.
Four measurements cover everything, and they take two minutes with a soft tape.
- Height. Against a wall, heels down, no shoes, a book flat on the head. This is the leading number from around twelve months onward.
- Weight. Weigh yourself, then yourself holding the child, and subtract. Close enough for clothing, and the leading number under twelve months.
- Chest. Around the fullest part under the arms, tape flat and not pulled. One finger of ease under it.
- Torso length, for anything one-piece. From the shoulder, down the front, through the crotch and back up to the same shoulder. This is what decides whether a footed sleeper or a bodysuit fits, and almost nobody measures it.
Two habits make this worth the effort. Write the numbers down with the date, in a note on your phone, because in three months you will not remember and re-measuring a mobile toddler is harder than it sounds. And measure over what the garment will sit on — a nappy and a thin vest for a baby, ordinary clothes for an older child.
The alternative that works almost as well: take a garment that fits well, lay it flat, and record chest across, total length and inside leg. Those three transfer between brands in a way a size label never does, and they are what to compare against a garment-measurement chart.
How to compare two brands without ordering from both
The question underneath “does PatPat run small” is usually a comparison with something the reader already owns, and there is a reliable method for that.
Work out which kind of chart you are reading. A size chart gives either body measurements (the size of the child the garment is drafted for) or garment measurements (the finished item laid flat). They are not comparable. The tell is the numbers themselves: garment measurements are larger than body measurements for the same size, because of the ease added by the pattern. If a chart does not say which it is, that is worth knowing before drawing any conclusion from it.
Then compare like with like:
- Body chart against body chart. Both describe the child, so the difference between them is a real difference in who the size is intended for.
- Garment chart against a garment you own, measured flat. This is the most reliable comparison available and the one that needs no trust in either brand.
- Never label against label. Two 3T garments are two independent decisions by two companies, and comparing the numbers compares nothing.
Watch for the three places charts quietly differ: whether a height range is the child’s height or the garment’s length, whether weight ranges overlap between adjacent sizes or butt up against each other, and whether the chart covers the whole range or only the sizes currently in stock.
Our own measurements, in both inches and centimetres, are on the PatPat size chart, and they are body measurements unless a product page states otherwise.
Reviews that say a garment runs small: how to read them
Review sections are the most-used sizing resource and the least reliable one, and a few patterns make them more useful.
- A review that gives a measurement is worth ten that do not. “My daughter is 98 cm and the 3T fits with room” is information. “Runs small” is not, because you do not know what it is small relative to.
- Look for the category, not the brand. Swimwear, sleepwear and outerwear are cut to different amounts of ease on purpose. A brand can be accurate in daywear and feel tight in swimwear without anything being inconsistent.
- Snug-fit sleepwear generates “runs small” reviews by design. It is drafted to maximum dimensions under a safety rule, so it is meant to be closer-fitting than daywear. Those reviews are describing the standard rather than a sizing error.
- Weight the reviews from people whose child is at the edge of a band. A child in the middle of a size range will find almost anything fits; the useful signal comes from the ends.
- Discount reviews about the wrong garment type. A comment about a dress tells you little about a bodysuit from the same brand.
The most common misreading in this category is treating “this feels tighter than I expected” as a sizing fault when it is a category difference. Sleepwear, swimwear and leggings are all supposed to be closer to the body than a t-shirt, and each of them generates the same review for that reason.
How to order so it fits the first time
- Measure height in centimetres and buy to it. Every PatPat kids and baby size is drafted to a height band. Height removes the naming systems from the decision entirely.
- For babies under two, weight decides. Babies of the same age vary far more in weight than in length, and the PatPat baby chart carries a weight band on every size.
- At 2T, take the next size up if the child is coming out of another brand's 24M.
- In the kids range, do not trust the digit. Read the height column, especially between US 6 and US 9.
- For adult pieces, add a letter, or better, measure the chest and match it on the chart.
- In sleepwear, order the size that fits now. Snug is the design.
- If anyone in the family needs an end size, start there. Pick the print after you know that size exists, not before. For matching family outfits this is the difference between a complete set and four out of five.
- Buying seasonal sets, check stock before you fall for a print. The Christmas pajama size guide sets the same charts against live stock for that collection.
Frequently asked questions
Does PatPat run small? Not uniformly. Baby sizes match the common US charts almost exactly, but 2T and the kids numbers 6 through 9 are cut for a shorter child, and women's letters run about one letter smaller.
Should I size up in PatPat pajamas? No, not in untreated cotton or bamboo sleepwear. Those are sold under the tight-fitting exception to the US children's sleepwear flammability standards, which caps their dimensions and requires them to be worn close to the body.
My child wears a 2T from another brand. What do I order? Order a 3Y or 3T. PatPat's 2T is drafted for 33 to 35 inches, which is where most US brands place 24M, while the 3Y covers 35 to 39 inches and is the closer match.
Is 2T the same as 2Y at PatPat? Yes, they are the identical draft — 83.8 to 88.9 cm and 28 to 30 lb. Which label appears depends on the product line rather than on the fit.
Why did two items in the same size fit differently? Because a woven and a knit drafted to the same chest measurement wear differently, and sleepwear is drafted tighter than daywear by regulation. A 4T pajama top and a 4T t-shirt are not built to the same ease.
What size is a youth medium? M(9-10Y) is a kids size, drafted for a child 134.6 to 139.7 cm tall and 71 to 84 lb — not an adult M. The full youth-letter run is XS(5-6Y) through XL(13-14Y).
How do I measure my child for a size chart? Height and weight first, then chest, then torso length shoulder to crotch and back. That last one decides whether anything one-piece fits.
How do I compare two brands without ordering from both? Measure a garment you own flat, and compare it against the other brand’s garment measurements. Comparing size labels compares nothing.
Is a body chart the same as a garment chart? No, and mixing them is the most common sizing mistake. Garment measurements are larger, because they include the ease the pattern adds.
Why do reviews say sleepwear runs small? Because snug-fit sleepwear is drafted to maximum dimensions under a safety rule. It is meant to be closer-fitting than daywear, so those reviews are describing the standard.
Which sizing reviews are actually useful? The ones that give a measurement. A height plus a verdict is information; a bare “runs small” is not, because you do not know what it is small relative to.
About this article
Written by the PatPat Editorial Team. How we research, source and review what we publish, and who is on the team, is set out on our editorial standards page.
Pattern and stock data verified by Alex Deng, Merchandise Director. Sleepwear safety section reviewed by Melody Zhao, Legal Affairs Manager, on 15 September 2026.
Published 15 September 2026.
Sources. PatPat figures are read from the PatPat size chart, which is generated from PatPat's own pattern data. Stock depth figures are a live-inventory snapshot dated 4 September 2026. Comparison figures are read from the published Carter's size chart. Regulatory statements are sourced to the US Consumer Product Safety Commission's guidance on children's sleepwear and on infant and tight-fitting garments. Standards history is sourced to ASTM D5826-00, withdrawn 2009 and to NIST.
Method. Both charts were read in full on 15 September 2026 and compared size by size. PatPat's centimetre figures were converted to inches for comparison and are rounded to the nearest half inch in the tables above. No garments were measured for this article. Where the charts disagree, both figures are shown rather than averaged.
Corrections. Anything in this article that does not match the charts as published should be reported to PatPat, and the article will be corrected with the change noted here.
Last updated 15 September 2026. Next review March 2027, or sooner if either chart changes.
