Why Fastening a Suit's Bottom Button Causes the Fabric to Pucker

Around the turn of the 20th century, King Edward VII—a British monarch with a legendary appetite and a 48-inch waist—found himself unable to fasten the lowest button of his lounge suit. Rather than order a redesign, he simply left the garment open at the hem.

The royal court, unwilling to out-dress or embarrass the king, quietly mirrored his adjustment. Dukes, earls, and visiting dignitaries began leaving their own bottom buttons undone, normalizing the monarch's silhouette and inadvertently launching a global trend.

"He unbuttoned the bottom of his waistcoat because he was too fat," notes fashion writer Jacob Shamsian in Business Insider. "When the lounge suit jacket started to become common as an everyday fashion, Edward VII kept the bottom button undone to pay homage to the riding coat style."

Within a single generation, that aristocratic habit permanently altered the physical construction of menswear. Tailors on London’s Savile Row realized that if the bottom button was never going to be fastened, the fabric around it no longer needed to overlap seamlessly.[3]

The Geometry of Open Quarters

Today, the rule of the bottom button is not just a nod to Edwardian etiquette; it is a structural requirement woven into the garment. Tailors began drafting suit patterns that assumed the bottom closure would remain open, redesigning the entire silhouette around that specific gap.[3]

The secret to this modern fit lies in the "quarters." In tailoring terminology, the quarters are the two lower front panels of the jacket that meet beneath the waist button. Their precise shape dictates how the bottom half of the suit interacts with the wearer's body.

"The quarters represent the lower front flaps of your suit jacket panels, the area below the bottom button," explains menswear expert Sven Raphael Schneider of the Gentleman's Gazette. "These can be either open or closed, meaning the flaps can lie nearly straight down or spread apart in a cutaway fashion."

In contemporary tailoring, these lower panels are rarely cut straight down. Instead, they are drafted as open quarters. This means the fabric is deliberately curved and cut away, flaring outward from the center line to accommodate the natural width of the human hips.

This flared geometry serves a highly specific visual purpose. By sweeping away from the waist, open quarters expose a small triangle of the trousers and shirt. This optical trick elongates the appearance of the legs and creates a modern, athletic silhouette with broader-looking shoulders.

Mechanical Strain and Fabric Distortion

Because the pattern is explicitly cut to diverge at the hem, forcing the bottom button closed introduces severe mechanical strain. Worsted wool and linen blends possess a strict lateral tension limit, and they are not designed to stretch horizontally across the hips.[1]

When the bottom button anchors the flared quarters together, it pulls the fabric across the pelvis, exceeding that mechanical drape limit. The tension immediately causes the material to buckle, creating an unsightly, radiating "X" crease that points directly toward the fastened button.[1]

The resulting distortion ruins the suit's carefully engineered drape. The horizontal pulling at the hem travels upward, dragging the lapels out of their intended alignment. Instead of lying flat against the chest, the lapels bow outward, creating a hollow gap that ruins the jacket's profile.[1]

Furthermore, forcing the quarters together causes the rear vents to splay open. Because the front of the jacket is pulled too tight, the back panels are dragged forward, exposing the seat of the trousers and causing the hem to billow awkwardly around the thighs.[1]

Internal Canvas and Structural Support

The internal construction of a modern suit jacket further explains why the bottom button must remain untouched. High-quality suits rely on a layer of horsehair canvas sewn between the wool and the lining to give the chest and lapels their structured, three-dimensional shape.[2]

In a half-canvas suit—the most common construction method used today—this rigid internal support stops exactly at the waist button. Below that anchor point, the front panels hang freely, relying entirely on gravity and the weight of the wool to maintain their shape.[2]

Without the stiff canvas backing to reinforce the lower quarters, the fabric lacks the rigidity needed to support a fastened closure. Fastening the bottom button on an uncanvassed hem simply crumples the delicate wool, destroying the clean lines the tailor worked so hard to build.[2]

Sitting, Standing, and Movement Dynamics

The flared cut of open quarters also provides a crucial functional benefit: freedom of movement. Leaving the bottom button undone allows the jacket panels to slide smoothly over the trousers and pockets when the wearer walks, preventing the fabric from catching or riding up.[1]

When a wearer transitions from standing to sitting, the geometry of the suit changes entirely. Even with the bottom button correctly left open, sitting down forces the hips to expand and the thighs to rise, which pushes against the tailored lines of the jacket.[1][2]

For this reason, sartorial etiquette demands that a single-breasted jacket be unbuttoned entirely before taking a seat. Leaving the waist button fastened while seated drives the collar up into the neck and places immense stress on the button thread, risking a tear.[1][2]

Applying the Rule Across Jacket Styles

This structural reality applies across almost all single-breasted designs, though the exact execution depends on the button count. On a standard two-button business suit, the top button secures the natural waist, while the bottom remains strictly decorative to preserve the quarter flare.[1]

For traditional three-button styles, tailors rely on the "Sometimes, Always, Never" mnemonic. The wearer may sometimes fasten the top button, should always fasten the middle anchor button, and must never touch the bottom button, ensuring the skirt of the jacket hangs correctly.[2]

The one-button suit, often seen on tuxedos and evening wear, simplifies the equation entirely. Because the single button is positioned perfectly at the waist pivot point, it is always fastened when standing, and the quarters are cut to sweep away immediately below it.

The only notable exception to the bottom-button rule is the double-breasted suit. Because double-breasted jackets are drafted with overlapping front panels designed to wrap securely around the torso, they rely on a fully fastened front to maintain their structured, formal silhouette.[1]

Even on a double-breasted jacket, however, some modern wearers choose to leave the lowest interior anchor button undone to allow for a slight relaxation at the hip. For every other suit style, leaving the bottom button open is the only way to let the tailoring work as intended.[1]