Unbound Merino doesn't sell in stores, so the size you click is the size you commit to until an exchange ships back and forth. The brand's own aggregate fit data, pulled from customer reviews, says its best-selling tees run true to size on average. Averages hide the two situations that actually cause returns: a narrow, petite frame caught between two sizes, and a long torso paired with a crew-cut sleeve. Both have a fix. Here's the chart, the real fit data behind it, and where it breaks down.
The Official Size Chart
Unbound Merino publishes separate body-measurement charts for men's and women's tops, both in inches and centimeters. These are the men's Merino Crew Neck numbers, in inches:
| Size | Neck | Chest | Waist |
|---|---|---|---|
| S | 14–14.5 | 37–38 | 29–30 |
| M | 15–15.5 | 39–40 | 31–32 |
| L | 16–16.5 | 41–42 | 33–34 |
| XL | 17–17.5 | 43–44 | 35–36 |
| XXL | 18–18.5 | 45–46 | 37–38 |
Women's Merino Crew Neck, in inches, with the matching US dress size for reference:
| Size | Chest | Waist | US size |
|---|---|---|---|
| XS | 31.5–33 | 24–25 | 0–2 |
| S | 33.5–35 | 26–27 | 4–6 |
| M | 35.5–37 | 28–29 | 8–10 |
| L | 37.5–40 | 30–32 | 12–14 |
| XL | 40.5–43 | 33–35 | 16–18 |
| XXL | 43.5–47 | 36–39.5 | 20–22 |
The brand fits its sample models to that chart, not to a marketing ideal: the men's product photos are shot on a 6'2" model wearing a Medium, and the women's on a 5'9" model with a 32" bust wearing a Small — both mid-chart for their size, which is a reasonable way to judge what "true to size" looks like on a normal build. The cut itself is described as a classic fit: "not too loose, not too snug — just straight cut through the chest and waist," built for ease of movement rather than a slim or athletic taper.
Is Unbound Merino True to Size? What the Fit Data Actually Shows
Every review on the men's and women's Merino Crew Neck includes a fit rating on a scale from −2 (runs small) to +2 (runs big). Across 5,029 reviews, the men's crew averages effectively 0.0 — true to size. Across 2,221 reviews on the women's crew, same result: 0.0. That is a genuinely large sample for a direct-to-consumer apparel brand, and it's a stronger signal than the usual "true to size" line every clothing site prints regardless of what the reviews say.
What the average doesn't tell you is the spread. One five-star reviewer, Johanna Y., wrote about the women's crew: "Usually wear size medium in other brands and this is a generous medium" — a +1 fit rating, meaning it ran slightly big on her specifically, inside a product that averages dead-center true to size. Averages are a starting point, not a guarantee for your build. Before you order a piece outside the crew tee — a hoodie, a polo, joggers — check that specific product's own fit rating rather than assuming the brand's overall reputation carries over; Unbound Merino shows this rating on every product page, and it can skew differently piece to piece.
If You're Petite or Narrow-Shouldered
This is the fit complaint that shows up most in independent travel and merino-wool communities. One buyer, 5'0" and 100–105 lbs with narrow shoulders, posted the same question in both r/capsulewardrobe and r/HerOneBag: stuck between XS and S, worried about ending up either boxy or too tight.
"I'm petite and they don't have a lot of options. Looking at their classic crew neck shirts and I'm having a hard time choosing between XS or S. I want it to fit just right, not too baggy, and not too fitted."
— r/HerOneBag, February 2026
One reply in that thread made a broader point worth knowing before you order anything from any merino brand: "most merino brands run long. So many brands' tshirts are practically dresses on me." That's a general observation about the category, not a claim about Unbound Merino specifically — but it's the right question to ask before you buy: check torso length against your own height, not just chest measurement against the size chart.
The practical fix Unbound Merino offers directly: the women's line has a dedicated Petite sizing option (linked from every women's top's size selector), built for shorter torsos and narrower frames rather than just scaling a standard cut down. If you're under about 5'3" or have narrow shoulders relative to your bust, start there rather than guessing between two standard sizes.
If You're Tall or Long in the Torso
The mirror-image problem shows up in a longtime buyer's review of the standard men's crew neck:
"I like a bit longer shirts and their long sleeves are long enough in the torso but for some reason their short sleeves are not. I emailed them about it but they didn't have any good response."
— Cat49er, r/MerinoWoolGear, May 2026
That's a specific, useful data point: on this buyer's build, the long-sleeve crew and the short-sleeve crew are not cut to the same torso length, even in the same nominal size. If torso length matters to you more than sleeve style, don't assume the two sleeve options behave identically — and check the dedicated Tall sizing line (linked from the men's size selector) before defaulting to a size up in the standard cut, which fixes chest room but not torso length.
Fabric Weight Isn't the Same Across Every Piece
The Merino Crew Neck — men's and women's alike — is 100% superfine Merino wool jersey at 190gsm and 17.5 microns. That micron count is what keeps it from feeling like a scratchy sweater; anything above about 24 microns starts to read as itchy against skin, and 17.5 is well inside the soft range.
Other pieces in the catalog aren't necessarily built to the same weight. Buyers comparing hoodie versions on r/onebag cross-checked the fabric tags and found the blend itself changes between versions — an older run at 97% merino / 3% elastane, a newer one at 78% merino / 17% nylon / 5% spandex — and that the women's and men's Compact Travel Hoodie are cut from different weights (one buyer's tag check put the women's at 250gsm against the men's 180gsm). Take the exact gsm as buyer-reported rather than official spec sheet, but the underlying point holds either way: don't assume every Unbound Merino product shares the crew tee's weight and stretch. Check the fabric details listed on that specific product page before you buy, especially if you're ordering a hoodie or joggers rather than the flagship tee.
Travel Pants: Check the Waistband Before You Buy
Fit complaints on bottoms cluster around one detail — the waistband — and it differs by product line. A reviewer of the standard Travel Pants flagged this directly:
"I got some travel pants which I really like but I'm worried about them getting looser over time — they only have an elastic band, no draw string."
— Cat49er, r/MerinoWoolGear, May 2026
Compare that with an Unbound Merino team member answering a question about the separate Lounge Pants on r/MerinoWoolGear:
"I really like that they have both a zipper and a drawstring waistband. For a 14-hour flight, compression socks are a game changer..."
— Unbound Merino team member (self-identified), r/MerinoWoolGear, July 2026
Those are two different pants (Travel Pants vs. Lounge Pants), not a contradiction — but it means the waistband construction is a genuine point of difference between styles in this catalog, not a detail you can assume. If a secure, adjustable waist matters for a long flight or if you expect your weight to shift over a trip, check whether the specific pair you're ordering has a drawstring before you buy the elastic-only version.
Once You've Got Your Size
The three pieces this guide's fit data covers most directly — start here if you're ordering for the first time:
Men's Merino Crew Neck T-Shirt
5,029 fit ratings · true to size
190gsm, 17.5-micron superfine wool. Classic cut, straight through the chest — the piece this guide's chart and fit data are built around.
Women's Merino Crew Neck T-Shirt
2,221 fit ratings · true to size
Same 190gsm fabric and true-to-size average as the men's cut. Check the Petite line first if you're under 5'3" with narrow shoulders.
Compact Travel Hoodie
Heavier gsm than the crew tee
The one piece in this guide where the fabric spec changes by version and by gender — check that product page's own fit rating before ordering your usual size.
FAQ
Does Unbound Merino run small?
No, not on average. The two flagship crew tees average a true-to-size fit rating across more than 7,000 combined reviews. Individual results vary — some reviewers report a slightly generous fit, a few report snug — which is why checking the specific product's own rating matters more than the brand's overall reputation.
What if I'm between two sizes?
Match to your chest measurement first; the classic fit is cut for room through the chest and waist rather than a tapered athletic cut, so sizing to chest rather than habit-size in other brands is the more reliable approach. If you're petite with narrow shoulders, check the dedicated Petite line before splitting the difference between XS and S in the standard cut.
Does Unbound Merino offer petite or tall sizing?
Yes — Petite sizing is available on the women's line, and Tall sizing on the men's line, both linked directly from the standard size selector on each product page.
Can I exchange for free if the size is wrong?
Unbound Merino advertises free, easy exchanges at checkout on its product pages, which is the standard path if the chart and the fit-rating data still don't land you on the right size the first time.
Disclosure: the product links on this page are affiliate links. If you buy through them, this site may earn a commission at no extra cost to you. Size charts, fabric specs, and customer fit ratings are Unbound Merino's own published data as of the date shown; direct buyer quotes are sourced from public Reddit threads and attributed above.