Between Sizes? When to Size Up and When to Size Down in Athletic Wear
Designed in Scottsdale, Arizona
Between sizes? The fabric decides, not the tape measure.
Stretch content, compression and whether a garment is pre shrunk tell you more than any size chart. Here is how to call it, garment by garment.
When you land between two sizes, size down in anything with real stretch or compression, and size up in anything mostly cotton or built over a lining. That single rule covers most of what is in your cart. A polo with 16 percent spandex behaves nothing like a cotton tee, and treating them the same is why half of returns happen.
The 15 second version
- Stretch above roughly 10 percent spandex. Size down. The fabric closes the gap.
- Compression. Size down. It is supposed to feel firm in the mirror.
- Cotton or a cotton blend. Size up if you want room, stay put if you want it tailored.
- Anything with a built in short or bra. Size up. The liner is the limiting layer, not the outer fabric.
- A drawstring waist. Ignore the waist number entirely and size on your thigh or hip.
Ask what the fabric is doing before you ask what the chart says
A size chart measures a garment lying flat. It cannot tell you how that garment behaves on a body that moves.
Performance fabric with four way stretch is engineered with less ease built in than a woven cotton shirt, because the stretch is supposed to supply the room instead of the cut. That is the whole reason a large in performance fabric can feel like a medium in cotton. It is not a sizing error, it is the design working. Our athletic wear fit guide covers what each measurement is actually telling you.
The second question is whether the garment is pre shrunk. If it is, what you try on is what you keep. If it is not, you are sizing for a shirt that no longer exists after the first hot wash, and the safe move is up. Every PILLAR tee and the David Polo are pre shrunk, which is why sizing down is safe here and would not be at a brand that skips that step. Wash habits still matter, and the care guide is the cheapest insurance on any of this.
Size down in these five situations
All five have the same tell. Something in the garment is already doing the job that extra fabric would do.
- Compression leggings and sports bras. Support comes from tension. Size up and you have bought a soft legging at a compression price.
- Polos and tees with 10 percent spandex or more. The shirt will relax across the chest within an hour of wearing it.
- Anything pre shrunk. There is no future shrink to leave room for.
- A slim or tailored fit you want to read as tailored. Sizing up on a slim cut does not make it a relaxed cut. It makes it a slim cut that fits badly in the shoulders. If you are not sure which cut you are holding, athletic fit versus slim fit versus classic fit decodes the three labels.
- Layering pieces cut slim on purpose. A vest that is one size too big flaps in wind, which is the only weather where you actually need it.
Size up in these four situations
- Cotton and cotton blends. Cotton has no recovery. Whatever it gives, it keeps.
- Anything with a built in short or a built in bra. The liner runs tighter than the shell. A dress or skirt is only as comfortable as what is under it.
- You are between sizes on your shoulders. Shoulders are the one measurement nobody can alter and stretch cannot fix. Size to the shoulder, every time.
- You plan to tuck it. A tucked shirt needs length you do not see on the hanger. This matters most with a U cut hem, which is shorter at the sides by design.
Decoded: what each fit name is actually promising
Fit names are not standardised across the industry. These are what they mean on PILLAR product pages, with the fabric that backs them up.
| Fit name | What it means | Between sizes |
|---|---|---|
| Classic athletic fit | Tapered through the waist, cut for shoulders and a chest. Not slim, not boxy. David Polo, 84 percent nylon and 16 percent spandex. | Take the smaller size |
| Tailored fit | Closer through the body than classic, still with room to move. Maddie Polo, 88 percent polyester and 12 percent spandex. | Take the smaller size |
| Slim fit | The closest cut in the line. Nick Tee, 60 percent cotton, curved hem. | Size up if you want it easy, stay put if you want it slim |
| Medium compression | Active tension that holds through a workout. Luna Legging, 78 percent nylon and 22 percent spandex. | Take the smaller size |
| Built in liner | A shell over a functional short or bra. Tori Dress and Ellie Skirt. | Take the larger size |
If you want the longer version by body type rather than by garment, the polo fit guide and the athletic dress fit guide both start from your build instead of the label.
Men's picks, with the call already made
True to size
David Polo in Navy
Classic athletic fit, pre shrunk, 84 percent nylon with 16 percent spandex. That much stretch plus a pre shrunk finish means the shirt will not move on you after a wash. Between sizes, take the smaller one.
$76.00
True to size, size up for relaxed
Joey Tee in Black
Tailored fit, straight cut hem, 60 percent cotton with 35 percent rayon and 5 percent spandex. The cotton content is the reason this is the one tee here where sizing up is a real choice rather than a mistake.
$45.00
Size down
Drew Short 5 inch in Black
A drawstring waist solves half a size in either direction, so the waistband is not the deciding factor. Pick the size that fits your thigh and let the drawstring handle the rest.
$55.00
The true to size test pair. Joey Tee in black and Drew Short 5 inch in black, both medium, both in stock. If these fit, your PILLAR size is settled across the line. $100.00.
Add bothWomen's picks, with the call already made
True to size
Maddie Polo in White
Tailored fit, 88 percent polyester with 12 percent spandex, U cut hem. Size on your shoulders and your bust, not your waist, because the hem is cut to skim rather than cling.
$70.00
Size down
Luna Legging in Black
Medium compression, 78 percent nylon with 22 percent spandex, no front seam. Compression fabric is supposed to feel tight in the fitting room. Sizing up here is the most common mistake and it costs you the support you paid for.
$65.00
Size up
Ellie Skirt in White
The pleats float, but the built in shorts underneath are 85 percent nylon with 15 percent spandex and they are what you actually feel. If your hips are between sizes, the liner decides it. Go up.
$72.00
The true to size test pair. Maddie Polo in white and Luna Legging in black, both medium, both in stock. One tailored top and one compression bottom is the fastest way to find your size in both directions. $135.00 before the women's discount.
Add bothThe return math nobody does
Ordering one size is a coin flip. Ordering two, keeping one and sending one back inside the 30 day window costs you a trip to a drop off and settles the question permanently. Free shipping starts at $75, so a second size usually pushes the order over the line anyway.
Sizing is also the whole ball game on a bulk order, where a bad call multiplies by fifty people. That is a different problem with a different method, laid out in how to size a company polo order. On the men's tee side, the five fit checks from seam to hem is the physical test to run once the box arrives.
Frequently Asked Questions
If I am between sizes, should I size up or size down?
Size down in stretch and compression fabric, size up in cotton and in anything with a built in liner. Performance fabric with 10 percent spandex or more is built with less ease than woven cotton, because the stretch supplies the room. Cotton has no recovery, so whatever it gives it keeps. Those two rules resolve most between sizes decisions without a tape measure.
Do performance polos run small?
They run closer to the body than a cotton polo, which reads as running small. It is a design difference rather than a sizing error. A performance polo with four way stretch is cut with less ease because the fabric moves with you. If you normally wear a large in a cotton polo and you want the same feel, a large in performance fabric is usually still correct, just closer through the chest for the first hour.
Should I size up in leggings?
No. Compression leggings are designed to feel firm when you put them on. Sizing up removes the tension that provides the support, and the waistband is more likely to roll during movement rather than less. If a compression legging feels tight standing still and comfortable once you move, that is the correct size.
Does pre shrunk fabric change how I should size?
Yes, and it is the single most useful thing on a product page. Pre shrunk means the garment has already been through the shrink it was going to take, so what fits in the mirror is what you keep. When a garment is not pre shrunk, you are sizing for something that will be smaller after the first hot wash, and sizing up is the safer call.
What measurement should I size to if my chest and waist are different sizes?
Size to your shoulders first, then your chest. A shoulder seam that sits off your shoulder cannot be fixed by fabric stretch or by a tailor without rebuilding the garment. Waist and length are far easier to live with or alter. For bottoms with a drawstring, size to your thigh or hip and let the drawstring handle the waist.
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