Size Chart

Trek Bikes Size Chart

Use this Trek Bikes Size Chart as a starting point when choosing cycling apparel, kids’ bikes, bike helmets, shoes, gloves, socks, warmers, and shoe covers. Fit can vary by product style, rider proportions, and personal preference, so always compare the chart with the product details before ordering.

Trek Men’s Apparel Size Chart

Measurements reflect body circumference, not product measurements. Measure around the chest, waist, and hips while standing naturally.

Size	Chest	Chest	Waist	Waist	Hip	Hip
	inches	cm	inches	cm	inches	cm
XS	33–35	84–89	27–29	68–74	33–35	84–89
S	35–37	89–94	29–31	74–79	35–37	89–94
M	38–40	96–102	32–34	81–86	38–40	96–102
L	41–43	104–109	35–37	89–94	41–43	104–109
XL	44–46	112–117	38–41	97–104	44–46	112–117
2XL	47–49	119–124	42–45	106–114	47–49	119–124
3XL	50–52	127–132	45–48	114–122	50–52	127–132

Men’s apparel fit profiles may include Pro Fit, Fitted, Semi-fitted, and MTB Semi-fitted. Check each product page to understand how close or relaxed the garment is designed to feel.

Trek Women’s Apparel Size Chart

Measurements reflect body circumference, not product measurements. Measure bust, waist, and hip while standing up straight.

Size	Bust	Bust	Waist	Waist	Hip	Hip
	inches	cm	inches	cm	inches	cm
XS (2–4)	32–33	81–84	24–26	61–66	33–35	84–89
S (4–6)	33–34	84–86	26–28	66–71	35–37	89–94
M (6–8)	34–36	86–91	28–30	71–76	37–39	94–99
L (10–12)	36–38	91–97	30–32	76–81	39–41	99–104
XL (12–14)	38–40	97–102	32–34	81–84	41–43	104–109
2XL (16–18)	41–44	104–112	35–38	89–97	44–47	112–119
3XL (18–20)	44–47	112–119	38–41	97–104	47–50	119–127
4XL (22–24)	48–51	122–129	42–45	107–114	51–54	130–137

Women’s apparel fit profiles may include Fitted, Semi-fitted, and MTB Semi-fitted. If you prefer a more relaxed feel, review the item’s fit notes before selecting a size.

Kids’ Bike Size Chart

Kids’ bikes are commonly sized by wheel diameter instead of adult frame size. Use the child’s age, height, and inseam together to choose the most suitable wheel size.

Age Range	Height	Inseam	Wheel / Bike Size
2–3 years	3'0"–3'3"	15"–18"	12"
4–6 years	3'5"–4'0"	16"–22"	16"
5–8 years	3'9"–4'6"	19"–25"	20"
8–11 years	4'1"–4'11"	23"–28"	24"
10–12 years	4'8" and up	25" and up	26"
13+ years	—	—	Small adult bike sizes may apply

Size brackets can overlap. If a child is older than 12 or taller than 4'8", compare smaller adult bike sizes as well as youth bike options.

Bike Helmet Size Chart

Measure head circumference around the brow and above the ears. Choose the helmet size that matches the measurement range.

Helmet Size	Fit Range
Toddler	46–50 cm
Child	48–52 cm
Youth / XS	50–55 cm
Small	51–57 cm
S/M	51–58 cm
Medium	54–60 cm
M/L	55–61 cm
Large	58–63 cm
X-Large	60–66 cm

Cycling Shoe Size Chart

Cycling shoe fit can differ from everyday footwear. Use heel-to-toe length and the shoe size conversion table together when choosing your size.

EU	US Men	US Women	UK Men	UK Women	CM	Heel-to-Toe
36	3.5	5	2.5	4	23	22.4 cm
37	4	5.5	3	4.5	23.7	23.1 cm
37.5	4.5	6	3.5	5	24	23.4 cm
38	5	6.5	4	5.5	24.3	23.7 cm
38.5	5.5	7	4.5	6	24.7	24.0 cm
39	6	7.5	5	6.5	25	24.3 cm
39.5	6.5	8	5.5	7	25.3	24.6 cm
40	7	8.5	6	7.5	25.7	25.0 cm
40.5	7.5	9	6.5	8	26	25.3 cm
41	8	9.5	7	8.5	26.3	25.5 cm
41.5	8.5	10	7.5	9	26.7	25.9 cm
42	9	10.5	8	9.5	27	26.2 cm
42.5	9.5	11	8.5	10	27.3	26.5 cm
43	10	11.5	9	10.5	27.7	26.9 cm
43.5	10.5	—	9.5	—	28	27.1 cm
44	11	—	10	—	28.3	27.4 cm
44.5	11.5	—	10.5	—	28.7	27.8 cm
45	12	—	11	—	29	28.1 cm
45.5	12.5	—	11.5	—	29.3	28.3 cm
46	13	—	12	—	29.7	28.7 cm
46.5	13.5	—	12.5	—	30	29.0 cm
47	14	—	13	—	30.3	29.3 cm
48	14.5	—	13.5	—	31	29.9 cm
49	15	—	14	—	31.7	30.6 cm

If you are between cycling shoe sizes, round up to the nearest size. If your feet are different lengths, choose based on the longer foot.

Cycling Glove Size Chart

Measure around the hand with a soft tape measure. Choose the size range that matches your hand circumference.

Men’s Size	Women’s Size	Hand	Hand
		cm	inches
XS	—	16–17.5	6.5–7
XS	S	17.5–19	7–7.5
S	M	19–20.5	7.5–8
M	L	20.5–23	8–9
L	—	23–25.5	9–10
XL	—	25.5–28	10–11
2XL	—	28–30.5	11–12

Arm Warmer Size Chart

Measure the length of the arm warmer area, bicep circumference, and wrist circumference.

Size	Length	Length	Bicep	Bicep	Wrist	Wrist
	inches	cm	inches	cm	inches	cm
XS	< 17¾	45	< 10½	26	< 6¼	16
S	18⅛	46	10½–11½	27–29	6¼–6½	16–17
M	18½	47	11½–13½	29–34	6½–6¾	16–17
L	18⅞	48	13½–15½	34–39	6¾–7	17–18
XL	19¼+	49	15½+	39	7+	18

Knee Warmer Size Chart

Measure calf and thigh circumference to choose the best knee warmer size.

Size	Length	Length	Thigh	Thigh	Calf	Calf
	inches	cm	inches	cm	inches	cm
XS	< 14¾	37	< 17	43	< 13	33
S	15⅛	38	17–18½	43–47	13–14	33–36
M	15½	39	18½–20	47–51	14–15	36–38
L	15⅞	40	20–21½	51–55	15–16	38–41
XL	16¼+	41	21½+	55	16+	41

Leg Warmer Size Chart

Measure thigh circumference, ankle circumference, and warmer length to choose the correct leg warmer size.

Size	Length	Length	Thigh	Thigh	Ankle	Ankle
	inches	cm	inches	cm	inches	cm
XS	< 25¼	64	< 20	51	< 9	23
S	25⅞	65	20–21½	51–55	9–9½	23–24
M	26	66	21½–23	55–58	9½–10	24–25
L	26⅜	67	23–24½	58–62	10–10½	25–27
XL	26¾+	68	24½+	62	10½+	27

Sock Size Chart

Trek sock sizing is based on shoe size. Choose the sock size range that includes your shoe size.

Size	EU	US Men	US Women	UK
S	36–39	4–6	5.5–7.5	3–5
M	40–42	8.5–10.5	9.0–11.0	6–8
L	43–45	10–12	11.5–13.5	9–11
XL	46–48	13–15	N/A	12–14

Shoe Cover Size Chart

Shoe cover sizing is based on cycling shoe size. Select the range that includes your shoe size.

Size	EU	US Men	US Women	UK
S	< 40	< 7	< 8	< 6.5
M	40.5–42	7.5–9	8.5–10.5	7–8.5
L	42.5–44	9.5–11	11.5+	9–10.5
XL	44.5–46	11.5–13	—	11–12.5
2XL	46.5+	13.5+	—	13+

How to Choose Your Size

Start with the chart

Match the rider’s height, inseam, chest, waist, hip, hand, head, or foot measurement to the closest listed size range.

Check the product page

Product-specific sizing, geometry, and fit notes may vary by model, category, and design.

Think about comfort

A good fit should feel controlled, comfortable, and easy to handle during the type of riding you do most.

Do not size up too far

Choosing a bike, helmet, shoe, or apparel item that is too large can reduce comfort, control, and performance.

Measuring Tips

Measure height while standing straight against a wall without shoes.
Measure inseam from the floor to the top of the inner leg while standing naturally.
For apparel, measure chest or bust, waist, and hips with a soft tape measure held level.
For helmets, wrap a soft tape measure around the head, across the brow and above the ears.
For gloves, measure around the hand at the widest part.
For shoes, measure both feet and use the longer foot when selecting a size.
If using string for measurement, mark the string and measure it against a ruler.
Take measurements more than once to help avoid sizing mistakes.

Fit Notes

A kids’ bike should be easy to stand over and control. Younger riders may need more bend in the knees when seated, while more confident pedal-bike riders may prefer a slightly higher saddle position for smoother pedaling.

A helmet should sit level on the head, cover the forehead, and feel snug without being uncomfortable. After adjustment, the helmet should not slide forward over the eyes or backward away from the forehead.

Cycling apparel should match both body measurements and intended fit. Performance pieces may feel closer to the body, while trail or mountain-bike styles may allow more room for movement.

Between Sizes?

If you are between apparel sizes, choose based on your fit preference and the item’s intended silhouette. For a closer performance fit, choose the smaller size if your measurements fit comfortably within the range. For a more relaxed feel, consider the larger size.

For kids’ bikes, a slightly smaller and easier-to-control size is often better than a bike that feels too large. For helmets, gloves, and shoes, choose the size that can be adjusted securely without pressure points.

Product Detail Reminder

This guide is a general sizing reference. Always review the specific product page for model-level size guidance, geometry notes, fit ranges, apparel fit profiles, and any product-specific recommendations before placing an order.

Need Help?

If you need help choosing a size, contact Trek Bikes customer support at [email protected]. Please include the product name, the rider’s measurements, and any sizing questions you have.