Name: Youth GameDay Greats #1 Navy BYU Cougars Lightweight Baseball Jersey
SKU: YTHXS-PS3647
Price: 65.99 USD
Availability: InStock

Order first, worry later. Not sure between two sizes? Place the order with the size you think is right, then send your height, chest and waist measurements — plus hip for shorts and pants — through the order message or by email to fanservice2026@outlook.com. We check every sizing request against the charts on this page before the parcel is packed, and swap the size if a different one suits you better. You end up with the size that fits, not the size you guessed.

Start here

Measure at home

A tape measure gives you the answer in about a minute, and it is the difference between wearing the jersey and returning it. Measure over a single thin layer — a t-shirt, never a jacket — standing normally with your arms hanging down. A soft tailor's tape is easiest; if you do not have one, loop a piece of string around the spot, pinch the point where it meets, then lay the string flat against a ruler.

1. Chest — the number that matters most

Run the tape around the fullest part of your chest, right under the armpits. Keep it level all the way round and breathe out normally — do not pull your shoulders back to chase a smaller number.

2. Waist

Find the narrowest point of your torso, usually a finger or two above the navel, and measure there. Keep the tape snug but not cinched.

3. Hip — only needed for shorts and pants

Stand with your feet together and measure around the fullest part of your seat. This is the number that decides your size in anything below the waist.

4. Body length

Start at the highest point of the shoulder, beside the collar, and drop the tape straight down to wherever you want the hem to finish. Compare it with the body-length column before you commit.

5. Sleeve

For long-sleeve jerseys, jackets and hoodies: measure from the shoulder seam down to your wrist with the arm slightly bent. Outerwear uses a different method — see the jackets section below.

6. Inseam — for pants and joggers

Measure from the crotch straight down the inside of the leg to the ankle bone. This sets the length, not the width.

Where to look: chest decides jerseys, jackets and hoodies. Waist and hip decide shorts and pants. If your measurement lands in the gap between two rows, take the larger size — a jersey with a little room always looks better than one that pulls.

Before the charts

Which number counts

Sizing goes wrong when people compare the wrong measurement — a waist against a chest, or a garment width against a body number. The table below is the short version: match the garment you are buying to the body measurement that decides it, then go to that chart.

Body measurement by garment type — start with the first column, confirm with the second.

Garment	Decide by	Second check
Jerseys — all six leagues	Chest	Body length
Shorts	Waist	Hip
Pants & joggers	Waist	Inseam
Jackets & hoodies	Chest	Sleeve
Youth & toddler	Age band	Height
A full kit — jersey plus shorts	Chest for the top, waist for the bottom	Size the two pieces separately

Leagues covered

Measurement charts

135

Size rows in total

Units — inches & cm

Know your cut

Fit by league

The label on the collar is only half the story — the same letter means something different in each sport. A soccer medium hugs the body, a hockey medium hangs off the shoulders. Read the row for your league before you pick a number:

How each league cuts its jersey — read this before you pick a number.

League	Cut	What it feels like
Soccer	Athletic / slim	Close to the body; size up for a looser look
NBA	Standard / slightly long	Relaxed through the chest, longer hem
NFL	Roomy / boxy	Classic oversized game-day look
MLB	Full / button-front	Relaxed traditional baseball cut
NHL	Very loose	The loosest cut of all leagues — order your true size, no need to size up

Every fan-version and replica jersey we carry keeps the silhouette that league is known for, so the size you already wear in that sport is the size to order here. College kit is cut to the sport it is made for rather than to a separate NCAA scale — a college football shirt follows the football row above, a college basketball shirt follows the basketball one.

One number, six answers

One chest, six sizes

If you know your chest measurement, this is the fastest way through the page: find your row on the left, then read across to the league you are shopping.

Find your row by chest measurement, then read straight across to your league.

Chest — inches	Chest — cm	NFL	NBA	MLB	NHL	Soccer
33–35"	84–89	S	S	S	S	XS–S
35–37"	89–94	S	S–M	S–M	S	S
37–40"	94–102	M	M–L	M	S–M	M
40–43"	102–109	L	L	L	M	L
43–47"	109–119	XL	XL	XL	L	XL
47–51"	119–130	2XL	2XL	2XL	XL	2XL
51–55"	130–140	3XL	3XL	3XL	2XL	3XL
55"+	140+	4XL	3XL	3XL	3XL	3XL

The chest figures are your body measurements, not the width of a flat-laid garment — that is why they read smaller than the number you would get by measuring a jersey on a table. Between two rows? Take the larger size.

Once you have your letter, go straight to the shirts:

NFL jerseys — full and boxy, built to layer
NBA jerseys — standard cut, longer hem
MLB jerseys — button-front and relaxed
NHL jerseys — the roomiest cut of the six
NCAA jerseys — college kit in the sport it is cut for
Soccer jerseys — slim national team shirts

American football

NFL jerseys

Cut: full and boxy

NFL shirts are built the way they look on the sideline — generous through the chest and straight down the body, with room to pull over a t-shirt or a hoodie. If that layered, oversized look is what you are after, order your true size and let the cut do the work.

Men’s NFL chart

Men's NFL — the full, boxy cut, made to wear over a tee.

Size	Chest — in	Chest — cm	Waist — in	Body length — in	Body length — cm	Sleeve — in
S	35–38	89–97	29–32	29	74	17.5
M	38–41	97–104	32–35	30	76	18.5
L	41–44	104–112	35–38	31	79	19.5
XL	44–48	112–122	38–43	32	81	20.5
2XL	48–53	122–135	43–48	33	84	21.5
3XL	53–58	135–147	48–53	34	86	22.5
4XL	58–63	147–160	53–58	35	89	23.5

Women’s NFL chart

Women's NFL — tapered through the waist, shorter in the body.

Size	Chest — in	Chest — cm	Waist — in	Body length — in	Body length — cm
XS	31–33	79–84	25–26	26	66
S	33–35	84–89	26–28	27	69
M	35–38	89–97	28–31	27.5	70
L	38–41	97–104	31–34	28	71
XL	41–44	104–112	34–37	28.5	72
2XL	44–47	112–119	37–40	29	74

The women's version follows the body more closely through the waist and finishes higher on the hip. If you would rather have the loose, boxy silhouette, take a men's small or medium instead of sizing up in the women's chart.

Youth NFL chart

Youth NFL — sized by age band, chest and height together.

Size	Age	Chest — in	Chest — cm	Height — in	Height — cm
XS	5–6	24–25	61–64	44–48	112–122
S	7–8	26–27	66–69	50–54	127–137
M	9–12	28–30	71–76	55–60	140–152
L	13–15	31–33	79–84	61–63	155–160
XL	16–18	34–36	86–91	64–67	163–170

Youth XL covers most teenagers up to around 5'6" (168 cm). Past that height a men's small gives you the extra body and sleeve length a youth XL cannot.

Broad through the chest already, or planning to wear it over a hoodie? Order one size up from your row. Otherwise your true size is the right call.

Basketball

NBA jerseys

Cut: standard, with a longer hem

Sleeveless by design, with a hem that sits lower than most football shirts and a shoulder line that stays close to standard. Nothing to size around — match your chest and you are done.

Men’s NBA chart

Men's NBA — standard through the chest, hem sits lower than a soccer jersey.

Size	Chest — in	Chest — cm	Body length — in	Body length — cm	Shoulder — in
S	37–39	94–99	28.5	72	17
M	39–41	99–104	29.5	75	18
L	41–43	104–109	30.5	77	19
XL	43–46	109–117	31.5	80	20
2XL	46–49	117–124	32.5	83	21
3XL	49–52	124–132	33.5	85	22

Women’s NBA chart

Women's NBA — sleeveless, contoured, with a shorter hem.

Size	Chest — in	Chest — cm	Body length — in	Body length — cm
S	33–35	84–89	26.5	67
M	35–37	89–94	27	69
L	37–40	94–102	27.5	70
XL	40–43	102–109	28	71
2XL	43–46	109–117	28.5	72

Youth NBA

There is no separate youth basketball chart — youth NBA shirts use the same age-and-height scale as every other youth jersey on this page. Jump to the kids’ charts.

Baseball

MLB jerseys

Cut: button-front, relaxed

The classic buttoned front, cut full through the chest and body with the hem landing at the hip. It hangs straighter than a soccer shirt and does not taper at the waist — think of it as a jersey you can wear unbuttoned.

Men’s MLB chart

Men's MLB — button-front, relaxed through the body, hem at the hip.

Size	Chest — in	Chest — cm	Body length — in	Body length — cm	Sleeve — in
S	36–38	91–97	28	71	17.5
M	38–41	97–104	29	74	18.5
L	41–44	104–112	30	76	19.5
XL	44–48	112–122	31	79	20.5
2XL	48–52	122–132	32	81	21.5
3XL	52–56	132–142	33	84	22.5

Women’s MLB chart

Women's MLB — the same button-front cut with a shaped waist.

Size	Chest — in	Chest — cm	Body length — in	Body length — cm
S	33–35	84–89	26.5	67
M	35–37	89–94	27	69
L	37–40	94–102	27.5	70
XL	40–43	102–109	28	71
2XL	43–46	109–117	28.5	72

Ice hockey

NHL jerseys

Cut: the roomiest of the six

Hockey shirts are cut wide through the chest and body with noticeably longer sleeves, built to go over padding — which is why they feel enormous next to a soccer shirt of the same label.

Men’s NHL chart

Men's NHL — the roomiest cut we carry, with extra-long sleeves.

Size	Chest — in	Chest — cm	Body length — in	Body length — cm	Sleeve — in
S	40–43	102–109	30	76	24
M	43–46	109–117	31	79	25
L	46–49	117–124	32	81	26
XL	49–52	124–132	33	84	27
2XL	52–55	132–140	34	86	28
3XL	55–58	140–147	35	89	29

Expect the hockey cut to run one to two labels roomier than soccer or basketball. A 40-inch chest is a small here and a large in a soccer shirt — same body, two very different letters. Order your true chest size unless you actively want the oversized look.

Association football

Soccer jerseys

Cut: slim and athletic

The closest cut we stock, shaped to sit against the body the way match kit does. If you like your shirts loose, or you plan to wear something underneath, go one size up from your chart row rather than hoping it stretches.

Men’s soccer chart

Men's soccer — the closest cut of the six leagues; step up one if you like room.

Size	Chest — in	Chest — cm	Body length — in	Body length — cm	US	EU
XS	33–35	84–89	27	69	34–36	44
S	35–37	89–94	28	71	36–38	46
M	37–40	94–102	29	74	38–41	48–50
L	40–43	102–109	30	76	42–44	52–54
XL	43–47	109–119	31	79	46–48	56
2XL	47–51	119–130	32	81	50–52	58–60
3XL	51–55	130–140	33	84	54–56	62

Women’s soccer chart

Women's soccer — athletic cut with a shaped waist and short sleeves.

Size	Chest — in	Chest — cm	Waist — in	Body length — in	Body length — cm	US
XS	30–32	76–81	24–25	25	64	2–4
S	32–34	81–86	25–27	26	66	4–6
M	34–37	86–94	27–30	26.5	67	8–10
L	37–40	94–102	30–33	27	69	12–14
XL	40–44	102–112	33–37	27.5	70	16–18
2XL	44–48	112–122	37–41	28	71	20–22

Youth soccer

Youth soccer shirts use the shared youth scale further down the page. A youth XL hands over to a men’s small with almost no gap in between — see the kids’ charts.

For growing fans

Kids & toddler

Youth sizing is unisex and shared across all six leagues, so the same letter works whether the shirt is a football, basketball, baseball, hockey or soccer one. On the product pages these sizes appear as Youth XS–XL (listed as YthXS, YthS, YthM, YthL and YthXL), and toddler jerseys run 2T–4T. Right now youth and toddler sizes are stocked on our college teams — the pro-league shirts on this page carry the same letter scale, but the youth and toddler racks are NCAA territory. One habit worth keeping: when a child is near the top of an age band, take the next size up — they grow out of a jersey long before they wear one out.

Youth jerseys, ages 5–18

Youth, ages 5 to 18 — one unisex scale across all six leagues, stocked Youth XS–XL.

Size	Age	Chest — in	Chest — cm	Height — in	Height — cm	Weight — lb
XS	5–6	24–25	61–64	44–48	112–122	40–50
S	7–8	26–27	66–69	50–54	127–137	55–70
M	9–12	28–30	71–76	55–60	140–152	75–95
L	13–15	31–33	79–84	61–63	155–160	100–120
XL	16–18	34–36	86–91	64–67	163–170	125–145

Toddler jerseys, ages 2–4

Toddler, ages 2 to 4 — stocked on selected teams only.

Size	Age	Height — in	Height — cm	Chest — in	Chest — cm	Weight — lb
2T	2	33–35.5	84–90	21	53	26–29
3T	3	36–38.5	92–97	22	56	30–34
4T	4	39–41	99–104	23	58	35–39

Toddler sizes are stocked on selected teams only. Between 2T and 3T, take the 3T — the sleeves roll up, but the body cannot be stretched.

Below the waist, part one

Shorts

Waist and hip decide it

Basketball, soccer and training shorts are sized by your waist measurement, not by the jersey size you wear. Almost every style has an elastic waist with a drawstring, so one size covers a comfortable range — match your waist and you are done.

Men’s shorts chart

Men's shorts — waist and hip set the size, outseam sets the look.

Size	Waist — in	Waist — cm	Hip — in	Hip — cm	Outseam — in	Body length — cm
S	29–32	74–81	35–37.5	89–95	18–19	46–48
M	32–35	81–89	37.5–41	95–104	19–20	48–51
L	35–38	89–97	41–44	104–112	20–21	51–53
XL	38–43	97–109	44–48	112–122	21–22	53–56
2XL	43–47	109–119	48–52	122–132	22–23	56–58
3XL	47–52	119–132	52–56	132–142	23–24	58–61

The length column is the outseam, measured from the waistband down to the hem. Basketball shorts sit long, with a 9–11" inseam; soccer shorts are cut shorter, around 5–7", and trimmer through the leg — between two sizes there, take the larger one.

Women’s shorts chart

Women's shorts — a higher waist line and a slightly trimmer thigh.

Size	Waist — in	Waist — cm	Hip — in	Hip — cm	US
XS	24–25	61–64	33–34.5	84–88	2–4
S	25–27	64–69	34.5–36.5	88–93	4–6
M	27–30	69–76	36.5–39	93–99	8–10
L	30–33	76–84	39–41.5	99–105	12–14
XL	33–37	84–94	41.5–44.5	105–113	16–18
2XL	37–41	94–104	44.5–47.5	113–121	20–22

Women's shorts sit higher on the waist with a slightly narrower thigh than the men's version. If you would rather have length and room, a men's small is the simpler answer.

Youth shorts

Youth shorts follow the shared youth scale from section 10 — match the child's waist or weight to the same Youth XS–XL used for jerseys. Back to the kids’ charts.

Below the waist, part two

Jackets & hoodies

Cut: layer-friendly

Bombers, track jackets, windbreakers and hoodies are cut to standard outerwear sizing — roomy enough to pull on over a jersey or a tee. If yours will be worn over a hoodie in winter, order one size up and let the extra room work for you.

Men’s jackets & hoodies chart

Men's jackets and hoodies — roomy enough for a layer underneath.

Size	Chest — in	Chest — cm	Waist — in	Body length — in	Body length — cm	Sleeve — in
S	35–38	89–97	29–32	26–27	66–69	33.5
M	38–41	97–104	32–35	27–28	69–71	34.5
L	41–44	104–112	35–38	28–29	71–74	35.5
XL	44–48	112–122	38–43	29–30	74–76	36.5
2XL	48–53	122–135	43–48	30–31	76–79	37.5
3XL	53–58	135–147	48–53	31–32	79–81	38.5

Outerwear sleeve is measured from the centre of the back collar round to the cuff, not from the shoulder seam — which is why the figure looks longer than the sleeve number on a jersey chart. Same arm, different ruler.

Women’s jackets & hoodies chart

Women's jackets and hoodies — shaped through the waist.

Size	Chest — in	Chest — cm	Waist — in	Body length — in	Body length — cm
XS	31–33	79–84	25–26	23–24	58–61
S	33–35	84–89	26–28	24–25	61–64
M	35–38	89–97	28–31	25–26	64–66
L	38–41	97–104	31–34	26–27	66–69
XL	41–44	104–112	34–37	27–28	69–71
2XL	44–47	112–119	37–40	28–29	71–74

Cropped styles finish 2–3" above the length shown here. Where a style is cropped or deliberately oversized, the product page says so.

Youth jackets & hoodies

Youth outerwear uses the shared youth scale from section 10, sized by age and height. See the kids’ charts.

Below the waist, part three

Pants & joggers

Drawstring waist, regular inseam

Track pants and joggers close with a drawstring, so each size takes up a range rather than one exact figure. Match your waist first, then use the inseam column to check the length — the regular inseam runs from 5'6" to 6'1" (168–185 cm).

Men’s pants chart

Men's track pants and joggers — drawstring waist, regular inseam.

Size	Waist — in	Waist — cm	Hip — in	Hip — cm	Inseam — in	Inseam — cm
S	29–32	74–81	35–37.5	89–95	30–31	76–79
M	32–35	81–89	37.5–41	95–104	30.5–31.5	77–80
L	35–38	89–97	41–44	104–112	31–32	79–81
XL	38–43	97–109	44–48	112–122	31.5–32.5	80–83
2XL	43–47	109–119	48–52	122–132	32–33	81–84
3XL	47–52	119–132	52–56	132–142	32–33	81–84

Over 6'1" (185 cm)? Put your height in the order message and we will look for the longer-inseam stock first.

Women’s pants chart

Women's pants — waist first, then inseam for length.

Size	Waist — in	Waist — cm	Hip — in	Hip — cm	Inseam — in	Inseam — cm
XS	24–25	61–64	33–34.5	84–88	28.5–29.5	72–75
S	25–27	64–69	34.5–36.5	88–93	29–30	74–76
M	27–30	69–76	36.5–39	93–99	29.5–30.5	75–77
L	30–33	76–84	39–41.5	99–105	30–31	76–79
XL	33–37	84–94	41.5–44.5	105–113	30–31	76–79
2XL	37–41	94–104	44.5–47.5	113–121	30–31	76–79

Leggings-style pants in the women's range run a size close — take one up. Track pants follow the chart exactly as printed.

Youth pants

Youth joggers and track pants are sized on the shared youth scale by age and height. See the kids’ charts.

Shopping from outside the US

Size conversion

Our letters are US sizing. If you buy in European, UK, Italian, French, Japanese or Chinese sizes, convert to our letter first and then read the league chart for that letter — converting is only the first step.

Men’s tops

Men's tops — match your chest measurement to your local sizing system.

Our size (US)	EU / Germany	UK	Italy	France	Japan	China
XS	44	34	44	40	S	160/84A
S	46	36	46	42	M	165/88A
M	48–50	38–40	48–50	44–46	L	170/92A
L	52	42	52	48	XL	175/96A
XL	54	44	54	50	XXL	180/100A
2XL	56–58	46–48	56	52	3XL	185/104A
3XL	60	50	58	54	4XL	190/108A

Women’s tops

Women's tops — our US letter sizes laid against EU, UK, France, Italy and Japan.

Our size (US)	EU / Germany	UK	France	Italy	Japan
XS	34–36	6	36	38	5–7
S	36–38	8	38	40	9
M	38–40	10	40	42	11
L	40–42	12	42	44	13
XL	42–44	14	44	46	15
2XL	44–46	16	46–48	48	17

Treat this table as a guide rather than a guarantee — national systems vary by a size here and there, and two brands rarely agree in every row. If you own a tape measure, ignore the conversion completely and order straight from the chest column of your league chart.

Men’s bottoms — shorts & pants

Men's bottoms — waist-driven conversion; Japan is listed in waist centimetres.

Our size (US)	Waist — in	EU / Germany	UK	Italy	France	Japan
S	29–32	44–46	30–32	44–46	38–40	76–81
M	32–35	48	32–34	48	40–42	81–89
L	35–38	50	34–36	50	42–44	89–97
XL	38–43	52–54	36–38	52–54	44–46	97–109
2XL	43–47	56–58	38–40	56	48–50	109–119
3XL	47–52	60	40–42	58–60	52–54	119–132

The Japan column lists waist in centimetres, because Japanese bottoms are labelled that way. Everything else is a clothing letter.

Straight answers

Sizing questions

How do I work out my size from scratch?

Measure your chest, then look at the row for the league you are buying. That is the whole method. If the garment is shorts or pants, measure your waist and hip instead and use those charts — the measurement that decides the size is different for different garments, which is the single biggest cause of wrong orders.

My measurement sits between two rows. Which way do I go?

Up. Jerseys, jackets and hoodies are worn loose, and half an inch of extra room is invisible while a tight shirt is not. The one exception is hockey, where the cut is already very generous — there, stay on your true size rather than stepping up.

Are these charts in inches or centimetres?

Both. Every measurement column appears twice, once in inches and once in centimetres, so you can work in whichever unit your tape uses without converting anything in your head. The figures match after rounding to the nearest centimetre.

Does the same letter mean the same thing in every league?

No, and that catches people out. Soccer is the closest cut, basketball and baseball sit in the middle, football is full and boxy, and hockey is the loosest of the six. Plenty of customers wear a large in one sport and a medium in another. Check the chart for the sport you are buying, not the size in your wardrobe.

Men’s or women’s cut?

Women’s jerseys are shaped through the waist and finish higher on the hip; men’s jerseys run straight and boxy. Choosing the men's cut for the oversized look is a style decision, not a sizing mistake. If you normally wear a women’s size and switch to the men’s chart, go down one size.

At what point does a youth size stop working?

Youth XL covers up to roughly 5'6" (168 cm) and a 34–36" chest. Above that, a men's small is the better fit — it is longer in the body and the sleeve, so the shirt stops riding up.

Can I use my jersey size for shorts and jackets too?

Only as a rough guess. Jerseys and jackets are sized by chest; shorts and pants are sized by waist and hip. A jersey large next to a shorts medium is a completely normal combination — check each chart on its own rather than carrying one letter across everything you buy.

I ordered the wrong size. What happens now?

You are covered by our 30-Day Returns policy — read the full terms here. Send the item back unworn and we will swap the size. If you would rather get it right the first time, email fanservice2026@outlook.com with your measurements and the item you are looking at, and someone will reply within 24–48 hours with a size recommendation.

Graphics	Fully sublimated graphics with no raised stitching
Team and palette	BYU Cougars design in the navy colourway
Product type	Youth baseball jersey
Shipping and returns	Options and costs are shown at checkout before payment
Cut	Short sleeve, Full-button front
Sizing	Standard fan jersey measurements - size chart on this page
Material	92% polyester 8% spandex
Care	Machine wash inside out, cold, line dry
Wear it for	Game days, campus, travel and everyday wear

Youth GameDay Greats #1 Navy BYU Cougars Lightweight Baseball Jersey

Size Guide

Six leagues, one tape measure.