May 9, 2014 5:13 p.m. ET

THE VERY WORD "hemline" can summon visions of midcentury women's fashion and the Byzantine bylaws that simply had to be followed whenever imperious French designers raised and lowered skirt lengths. Those crazy dames, right?

Shown Above

From left: Shorts, $232,; Chambray Shirt, $165,; Jack Purcell Sneakers, $60, (worn with all looks)

Ovadia & Sons Shorts, $325, Bloomingdale's, 212-705-2000; Shawl Neck Cardigan, $71,; Crew Neck T-shirt, $17,

Baxter Shorts, $70,; Abingdon Crew Sweater, $220,; Cotton Tee, $20,

Fleets Shorts, $50,; Button-Down Shirt, $60,; Nautica Web Belt, $28,

Guys, you're in the same game. For most of the past two decades, men's shorts have barely merited the name, dropping so far down the calf that Linnaeus would have stuck them in the pants family. Call them what you want—knickerbockers, breeches, clam diggers—the one thing they haven't been is particularly short.

Finally that's changed. And given how change in the menswear world is measured—think millimeters per decade rather than centimeters per season for women's wear—shorts are shortening quickly. In the past few years, the low-water-mark length of a 15-inch-or-so inseam receded to knee-length (11 inches), then a knee-baring 9 inches, then to a quadriceps-exposing 7 inches and on to the newly fashionable thigh-flaunting 5 inches. If men's shorts were a glacier in Greenland, scientists would be freaking out.

One trendy company that's staked its business to an abbreviated hem is Chubbies, which makes and sells only men's shorts with a 5½-inch inseam, recalling Adidas soccer shorts of the 1970s and the Ocean Pacific trunks of the '80s (both of which are collectibles on eBay EBAY +1.44% eBay Inc. U.S.: Nasdaq $52.10 +0.74 +1.44% May 16, 2014 1:41 pm Volume (Delayed 15m) : 12.62M P/E Ratio N/A Market Cap $65.09 Billion Dividend Yield N/A Rev. per Employee $494,896 05/15/14 Tech Companies Object to FCC W… 05/15/14 Icahn Discloses New Stake in E… 05/14/14 Perry Capital Reports Increase… More quote details and news » EBAY in Your Value Your Change Short position ). The San Francisco-based company was founded in 2011 by four guys in their 20s who'd grown tired of the surf jams and cargo shorts they nearly drowned in during their teens.

"We spend too much time in the gym to hide under frumpy shorts that say, 'I don't care how I look,' " said Rainer Castillo, one of Chubbies' founders and the chief designer. The brand's goal is to bridge the divide between long cargo shorts and fussy, high-end designer short-shorts.

Produced in the U.S. in a range of sporty, casual and dressy renditions, and available via their website for around $50 each, Chubbies make a pretty good case for themselves. Still, Mr. Castillo said he is aware that there's a customer out there who's not ready to bare so much thigh; the company hopes to bring out a 7-inch inseam at some point. That measurement could prove to be a sweet spot of sorts—smack dab as it is between the conservative 9-inch and the 5-inch party boy.

For Atlanta-based menswear designer and retailer Sid Mashburn, the magic number is close to it. He does either a 7½- or 8-inch inseam. "I just don't like the longer lengths. They cut off your body in a strange place," said Mr. Mashburn. He added that he prefers to measure shorts by outseam (the measurement on the outside of the leg, from the waist to the hem) rather than the inseam, since the drop (the distance from the waist to the crotch) can vary as much as a few inches depending on the style. For the moment, however, he sticks to the traditional inseam in descriptions.

" If men's shorts were a glacier, scientists would be freaking out. "

It may be only 2 or so inches, but the difference between the Chubbies and Mashburns is meaningful. Chubbies' shorter length (and elastic waistband) dovetails with its irreverent vibe; the shorts are more weekend wear than cocktail fare. The company doesn't use typical poetic names for their colors. Khaki shorts aren't "bone" or "sand," they're "Khakmeisters."

By contrast, Sid Mashburn's styles have graduated from beer to vodka tonics. Made of cotton duck, seersucker or pincord and priced from $125 to $165, the shorts show enough leg to feel current without drawing too much attention. (For extra edge, Mr. Mashburn said, his tailor can sever the bottom hem, to finish them like cutoffs.)

However, many larger clothing companies believe that one length won't do for all customers. Menswear company Bonobos, which made its name with well-fitting men's trousers, hedges its bets when it comes to its $68 chino shorts, offering them in four lengths: 11, 9, 7 and 5 inches. J.Crew also offers four different lengths; Club Monaco has three. All make the inseam a prominent detail so guys can rest assured they know what they're getting—an approach that other online retailers should follow.

So, which length to choose? The 11-inch shorts, said Dwight Fenton, Bonobos' vice president of design, tend to work for guys in their teens who aren't up for very short. The 5-inchers, meanwhile, are favored by men in their 20s who want an on-trend look. "The same young guys wearing the slim-cut suits," Mr. Fenton said.

Other factors are obviously height and weight. Taller and leaner gents look better in longer and leaner shorts; shorter builds are better in shorter, boxier shorts. Tall and burly men, meanwhile, can benefit from showing a bit of leg in 7-inch shorts.

The ideal strategy, of course, is to have a few in different colors and lengths—giving you a pair for every occasion.

After all, summer is too short to spend it in long pants.