How should board shorts fit? Length, outseam and the on-the-knee rule

Most blokes buy board shorts by grabbing their usual size and hoping for the best. And then the shorts are either flapping around mid calf or they're so short and tight they only make sense at the beach. Fit is the whole difference between shorts you wear twice a summer and shorts you genuinely live in, and it comes down to a handful of numbers most brands never talk about.

We spent the better part of 2 years and more sampling rounds than we'd like to admit locking ours, so here's everything that actually matters.

How long should board shorts be?

On the knee. Standing relaxed, the hem should land right on the kneecap, and that's the length that gives you a relaxed, easy silhouette without tipping into either of the two failure modes.

Because mid calf is too long, that's the old surf comp look, and out of the water it wears you rather than the other way around. And the super short, slim 5 inch inseam goes too far the other way, it commits you hard to a beach context and gives up the relaxed drape that makes shorts comfortable to actually live in. On the knee is the spot, long enough to hang properly and feel relaxed, not so long that you're swimming in fabric on land.

What is an outseam, and why should you care?

The outseam is the measurement from the top of the waistband down the outside of the leg to the hem, and it's the number that actually decides where the shorts end on your body. It's way more useful than the inseam for shorts, because the inseam gets thrown around by how the rise is cut.

For reference, our size 34 runs a 56cm outseam with a 25.5cm inseam, which is what lands the hem on the knee for the average build. And if a brand publishes an outseam, you can compare it against a pair you already love in about ten seconds with a tape measure. If they don't publish one, well, that tells you something too.

Should board shorts be tight or loose?

Relaxed, but with intent. What you want is easy through the seat and thigh, anchored at the waist, and here's the test, you should be able to put your phone, your keys and a card in the pockets and still move like the pockets are empty, and you should be able to paddle, swim and surf in them, because that's what they're for. Tight shorts fail all of it, the fabric pulls when you sit, the pockets become decorative, and everything rides up the moment you're in the water.

But relaxed doesn't mean shapeless. The cut still has to hang well, because shorts you can surf in that look like you can only surf in them are half a product. The whole trick is a fit that's genuinely functional and still looks good standing at the bar, and that balance is a cut decision, not an accident of sizing up.

Why can't you find this fit anywhere?

Because the market split into two camps and left the middle empty. One camp makes fashion swim shorts, short, slim, mesh lined, great in a resort photo and useless for a real day. The other camp makes surf gear, long, baggy, technical, built for the lineup and looking like it everywhere else. Walk into any shopping centre and you can buy either extreme in fifty flavours.

What's missing is the pair in between, relaxed, on the knee, pockets that work, shorts you can surf in that still read as just a good pair of shorts. And that gap is basically the reason we started making them.

What size board shorts should I get?

Buy for your waist. Everything else follows.

Here's how sizing actually works behind the scenes, a brand builds one master size, gets it perfect, and grades every other size up and down from it, so if you get the waist right the hips, thigh and length all arrive in proportion. Get it wrong and nothing else can save you.

Two honest notes on how ours run, which is the kind of thing size guides usually won't tell you. Berties run relaxed, there's roughly a size more room in them than the label suggests, so if you're between sizes and want a neater fit, stay at your true waist size. And if you want a slightly longer, looser fit, size up, because the waist buckles let you cinch the waistband back in, so sizing up buys you length and room without the shorts going anywhere. That adjustability is exactly why we use clasps and buckles instead of relying on a drawstring knot.

Why we measure 12 points on every pair

Fit isn't one number, it's a system. Our production spec pins down 12 separate measurements per size, waist, hip at three points, front and back rise, outseam, inseam, thigh and leg openings, waistband height, even the pocket openings, and every sample that lands gets measured against that sheet point by point, with the deltas logged.

And we ended up here the hard way. A sampling round came back looking right and measuring wrong, and the drift only showed up once we compared it against a pair we knew was perfect. So we re-measured the best fitting pair we'd ever made, turned it into the master spec, and locked it with the factory. Now "fits like the good pair" isn't a vibe, it's a document.

That spec is what The Collective is cut to.

Frequently asked questions

Should board shorts cover your knees?

The hem should land on the kneecap, not past it. Mid calf coverage was a 2000s surf styling choice, not a functional one, and it's the single biggest thing that makes shorts read as beach only. On the knee gives you the relaxed length without the costume.

How do I know if my board shorts are too small?

The tell is the seat and the front rise, not the waist. If the fabric pulls flat across your thighs when you sit, or the front rise digs in when you squat, they're too small even if the waist feels fine. And if you can't sit down comfortably with a phone in the pocket, same verdict. Board shorts should let you forget you're wearing them.

Do board shorts stretch out over time?

Fixed waistband shorts hold their size far better than elastic waistbands, which relax with wear and heat. The fabric itself can give a little through the seat with heavy wear, which is one more reason to buy your true waist size rather than sizing down for a firm fit on day one.

Is a drawstring enough to hold board shorts up?

In the surf, yeah, that's what it's for. As an all day fitting system, no, because a knot is one fixed setting. A clasp plus adjustable buckles gives you a couple of centimetres of tuning either way, which honestly covers the difference between before lunch and after it.

More in this series: why board shorts zips break and can you wear board shorts to the pub?, plus board shorts vs swim trunks vs swim shorts.