Siren 4 Waterproof Boot

$180.00

$54.00

70% OFF

Color: Arbor

Size: 5

Size & Fit Guide

Merrell Size Chart

Footwear and clothing conversions for women, men and kids, in US, UK, EU, JPN and CM. Merrell footwear is sized by foot length, so matching the centimetre column is the most reliable way to get the right fit — and if you land between two sizes, take the larger one.

Women's Footwear US 5 – 11.5

JPN is your foot length in centimetres; CHN is the same length in millimetres.

Hiking, Trail, Casual & Water Shoes
US Women's	UK	EU	JPNcm	CHNmm
5	2.5	35	22	220
5.5	3	35.5	22.5	225
6	3.5	36	23	230
6.5	4	37	23.5	235
7	4.5	37.5	24	240
7.5	5	38	24.5	245
8	5.5	38.5	25	250
8.5	6	39	25.5	255
9	6.5	40	26	260
9.5	7	40.5	26.5	265
10	7.5	41	27	270
10.5	8	42	27.5	275
11	8.5	42.5	28	280
11.5	9	43	28.5	285

Women's Tops, Jackets & Shirts

Body measurements — inches with the centimetre equivalent below.

Fleece, Shells, Tees & Baselayers
Size	US	UK	Chest / Bustin / cm	Sleevein / cm	Waistin / cm
XXS	0	—	31–31.578.5–80	28–28.571–72	24–24.561–62
XS	2	6	32–3381–84	29–29.574–75	25–2664–66
S	4–6	8–10	34–3586–89	30–30.576–77	27–2869–71
M	8–10	12–14	36–3791–94	31–31.579–80	29–3074–76
L	12–14	16–18	38–4096–102	32–32.581–82	31–3379–84
XL	16	20	41–43104–109	33–33.584–85	34–3686–91
XXL	18	—	44–46112–117	34–34.586–88	37–3994–99

Women's Bottoms, Pants & Tights

Inseam is measured inside the leg, from the crotch to the bottom of the ankle.

Pants, Tights & Shorts
Size	US	UK	Waistin / cm	Hipin / cm	Inseamin / cm
XXS	0	—	24–24.561–62	33–33.584–85	3179
XS	2	6	25–2664–66	34–3586–89	3179
S	4–6	8–10	27–2869–71	36–3791–94	3281
M	8–10	12–14	29–3074–76	38–3996–99	3281
L	12–14	16–18	31–3379–84	40–42102–107	3281
XL	16	20	34–3686–91	43–45109–114	3384
XXL	18	—	37–3994–99	43–45109–114	3486

Waist ranges for XL and XXL follow the size progression of the chart.

Men's Footwear US 6 – 16

JPN is your foot length in centimetres; CHN is the same length in millimetres.

Hiking, Trail, Casual & Water Shoes
US Men's	UK	EU	JPNcm	CHNmm
6	5.5	39	24	240
6.5	6	39.5	24.5	245
7	6.5	40	25	250
7.5	7	41	25.5	255
8	7.5	41.5	26	260
8.5	8	42	26.5	265
9	8.5	43	27	270
9.5	9	43.5	27.5	275
10	9.5	44	28	280
10.5	10	44.5	28.5	285
11	10.5	45	29	290
11.5	11	46	29.5	295
12	11.5	46.5	30	300
12.5	12	47	30.5	305
13	12.5	48	31	310
14	13	49	32	320
15	14	50	33	330
16	15	51	34	340

Men's Tops, Jackets & Shirts

Body measurements — inches with the centimetre equivalent below.

Fleece, Shells, Tees & Button-Downs
Size	Neckin / cm	Chestin / cm	Sleevein / cm
S	14.5–1537–38	36–3891–96	33–33.584–85
M	15.5–1639–40	39–4199–104	34–34.586–88
L	16.5–1742–43	42–44107–112	35–35.589–90
XL	17.5–1845–46	45–47114–119	36–36.591–92
XXL	18–18.546–47	48–51122–130	37–37.594–95

Men's Bottoms, Pants & Shorts

Sized by measured waist rather than by a letter size where the style allows.

Hiking Pants, Convertible Trousers & Shorts
Size	Waistin / cm	Inseamin / cm
S	31–3279–81	31.580
M	33–3482–86	3282
L	35–3787–94	32.583
XL	38–4095–101	3384
XXL	41–43102–109	33.585

Men's to women's footwear

Merrell does not publish a direct men's-to-women's conversion, because every foot is different. Match your measured foot length in centimetres instead.

Wide and medium widths

Many hiking styles are offered in both Medium and Wide. A wide fit adds roughly one centimetre across the forefoot for the same length.

Kids' Footwear US 1 – 7

Covers little kids, toddlers, pre-school and grade school. Baby sizes for water shoes and sandals start at US 0 (EU 15.5 / 8 cm).

Kids' & Youth Shoes, Sandals & Water Shoes
US Kids'	UK	EU	Foot Lengthcm
1Little Kids / Toddler	0.5	16	8.5
2Little Kids / Toddler	1.5	17	9.4
3Little Kids / Toddler	2.5	18	10.2
4Little Kids / Toddler	3	20	11
4.5Little Kids / Toddler	3.5	20.5	11.4
5Little Kids / Toddler	4	21	11.8
5.5Little Kids / Toddler	4.5	21.5	12.4
6Little Kids / Toddler	5	22	12.9
6.5Little Kids / Toddler	5.5	22.5	13.3
7Little Kids / Toddler	6	23	13.7
7.5Little Kids / Toddler	6.5	23.5	14.1
8Little Kids / Toddler	7	24	14.6
8.5Little Kids / Toddler	7.5	24.5	15
9Little Kids / Toddler	8	25	15.4
9.5Little Kids / Toddler	8.5	25.5	15.8
10Little Kids / Toddler	9	26	16.2
10.5Big Kids / Pre-School	9.5	27	16.5
11Big Kids / Pre-School	10	28	17
11.5Big Kids / Pre-School	10.5	28.5	17.5
12Big Kids / Pre-School	11	29	18
12.5Big Kids / Pre-School	11.5	30	18.5
13Big Kids / Pre-School	12	31	19
13.5Big Kids / Pre-School	12.5	31.5	19.5
1Big Kids / Pre-School	13	32	20
1.5Big Kids / Pre-School	13.5	33	20.5
2Big Kids / Pre-School	1	33.5	21
2.5Big Kids / Pre-School	1.5	34	21.5
3Big Kids / Pre-School	2	35	22
3.5Big Kids / Grade School	2.5	35.5	22.5
4Big Kids / Grade School	3	36	23
4.5Big Kids / Grade School	3.5	36.5	23.5
5Big Kids / Grade School	4	37	24
5.5Big Kids / Grade School	4.5	37.5	24.5
6Big Kids / Grade School	5	38	25
6.5Big Kids / Grade School	5.5	38.5	25.5
7Big Kids / Grade School	6	39	26

Growing room

Leave about one centimetre — a thumb's width — between the longest toe and the front of the shoe. Any more and the foot will slide on descents.

Measure both feet

Children's feet grow unevenly. Trace both feet on the same sheet of paper, and always size to the longer one.

Unisex Footwear

Unisex sizing runs as men's sizing. Women should select a size and a half smaller than their normal US women's size — for example, unisex 7 equals men's 7 and women's 8.5.

Unisex Boots, Shoes & Trail Models
US Unisexruns as men's	US Women'sconversion	UK	EU	Foot Lengthcm
3.5	5	3	36.5	21.5
4	5.5	3.5	37	22
4.5	6	4.5	37.5	22.5
5	6.5	4.5	38	23
5.5	7	5	38.5	23.5
6	7.5	5.5	39	24
6.5	8	6	39.5	24.5
7	8.5	6.5	40	25
7.5	9	7	41	25.5
8	9.5	7.5	41.5	26
8.5	10	8	42	26.5
9	10.5	8.5	43	27
9.5	11	9	43.5	27.5
10	11.5	9.5	44	28
10.5	12	10	44.5	28.5
11	12.5	10.5	45	29
11.5	13	11	46	29.5
12	13.5	11.5	46.5	30
12.5	14	12	47	30.5
13	14.5	12.5	48	31
14	15.5	13	49	32
15	16.5	14	50	33
16	17.5	15	51	34

The 1.5 size rule

Unisex 7 = men's 7 = women's 8.5. So if you normally wear a women's 9, order a unisex 7.5. Never order your usual women's number in a unisex style.

Widths stay the same

A unisex style is built on one last. If the model is offered in Medium and Wide, the width choice applies to both men and women ordering the same size.

Men's Sandals

Sandals use a different UK conversion than shoes — a men's sandal US 9 is a UK 8, while a men's shoe US 9 is a UK 8.5. Do not assume your shoe size carries over.

Men's Sandals & Slides
US Men's	UK	EU	JPNcm
7	6	40	25
8	7	41	26
9	8	42	27
10	9	43	28
11	10	44	29
12	11	45	30
13	12	46	31
14	13	47	32
15	14	48	33
16	15	49	34

Women's Sandals

Sold in whole sizes only, so choose the size that matches your measured foot length.

Women's Sandals & Slides
US Women's	UK	EU	JPNcm
5	3	36	22
6	4	37	23
7	5	38	24
8	6	39	25
9	7	40	26
10	8	41	27
11	9	42	28

Adjustability

Most Merrell sandals use hook-and-loop straps at the heel, instep and forefoot, so minor width and volume differences can be tuned on the foot.

Water shoes

Closed water shoes follow the standard footwear chart. If you plan to wear them with neoprene socks, take the next half size up.

How to Measure Your Foot

Merrell sizes its footwear by foot length, so this is the measurement that matters most.

Prepare the paper

Place a sheet of paper on a hard floor against a wall, and put on the socks you will wear with the shoe.

Trace your foot

Stand with your heel touching the wall and your foot perpendicular to it. Draw a line just in front of your longest toe.

Measure both feet

Repeat on the other foot, then measure from the wall to each line. Use the longer measurement.

Match the chart

Find your length in the JPN column and read across to your size. If you fall between two sizes, take the larger one.

Check the toe box

Once the shoe is on, you should be able to press a thumb's width between your longest toe and the front of the shoe.

How to Measure Clothing

Bust / Chest

With arms relaxed at your sides, measure around the fullest part of the chest or bust, keeping the tape level.

Waist

Measure around the natural waistline — the smallest part of the waist, above the hip bones.

Hips

Standing with legs together, measure around the fullest part of the hips and seat.

Neck

Measure around the base of the neck where a collar would sit, keeping one finger under the tape.

Sleeve

Measure from the middle of the back, over the shoulder and down a slightly bent arm to the wrist.

Inseam

Measure the inside length of the leg from the crotch to the bottom of the ankle.

Finding Your Merrell Fit

Hiking & backpacking

The Moab family and most leather hikers run true to size with a roomy toe box and a secure heel hold. Take your measured length.

Trail running

Faster, lower-volume models fit closer to the foot. Runners with wide feet or who expect foot swell over long distances should go half a size up.

Barefoot collection

Zero drop, minimal cushioning and a wide toe box. Size by length as usual, but expect a very different feel underfoot — build up mileage slowly.

Waterproof models

A waterproof membrane slightly reduces internal volume. If you wear thick socks, some hikers prefer half a size up.

Sandals

Sandals have their own conversion, different from shoes and boots. Always check the sandal chart rather than reusing your shoe size.

Between two sizes?

Merrell recommends taking the size above. For footwear this is the safer choice; for clothing, follow the fit note on the product.

Care & Returns

Returns: unworn, unwashed and unaltered items can be returned within 30 days.
Footwear: try shoes on indoors first — worn outdoors they may not qualify for return.
Care: air dry footwear at room temperature, away from direct heat. Never machine wash or tumble dry.
Cleaning: brush off dried mud, then wipe with a damp cloth and mild soap. Refresh waterproofing as needed.

Conversions follow Merrell's published size guides for women's, men's, kids', unisex and sandal footwear, plus men's and women's clothing. Measurements are approximate and provided for reference only.

Quantity

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