The Ultimate Guide to Formal Vest Fit: Tips for a Perfect Look

A well-fitted vest is the unsung hero of formal menswear. While the jacket and trousers often steal the spotlight, the vest quietly pulls everything together, adding a layer of sophistication and structure that takes your outfit from "good" to "great." 

But, like any tailored piece, the key to pulling off a vest lies in the fit. Whether you're eyeing a single-breasted or double-breasted style, nailing the fit is crucial for achieving that sharp, polished look.

So how should a suit vest fit? Below is a complete guide. Check out more fit guides here.

Just like a great jacket, the fit of your vest begins with the neckline. A well-fitted vest should hug the neck evenly all around, providing a solid foundation for the rest of the garment. The neckline sets the tone for how the vest will drape across your torso.

Another key factor? Button placement. For more formal vests—think black-tie or tuxedo attire—the buttons are typically placed lower, creating a deep V-shape reminiscent of a cummerbund. This design elongates the torso, offering a sleek silhouette. By contrast, suit vests tend to have a higher button placement, lending a more conservative and professional look.

Now, let’s get into the main differences between the two styles—because when it comes to vests, one size (or fit) definitely doesn’t fit all.

1. Single-Breasted Vest Fit

The single-breasted vest is the go-to for most men, and for good reason. Simple, versatile, and universally flattering, it's the classic choice.

• Neckline: The neckline of a single-breasted vest should sit snugly against your shirt collar, maintaining a streamlined, sleek look. Any gap between your shirt and vest throws off the polish.
• Button Placement: Single-breasted vests typically feature 3 or. 4 buttons placed around the midsection.
• Length: Rule number one: your vest should always cover the waistband of your trousers (in front and bck). Visible waistbands break the clean lines of your outfit and make the vest appear too short.
• Armholes: These should be snug but not restrictive. The goal is to create a clean silhouette without any pulling or discomfort
• Chest Fit: The vest should drape smoothly over the chest without billowing or pulling. You want enough room for movement, but not so much that it causes wrinkles or frumpy fabric.

2. Double-Breasted Vest Fit

Double-breasted vests are a little bolder and more sartorial. With two rows of buttons and an overlapping front, the double-breasted vest offers a more robust, elegant look.

• Neckline: Just like the single-breasted style, the neckline of a double-breasted vest should hug your neck snugly. The extra fabric at the front makes getting this right even more critical to avoid any bulkiness.
• Length: Again, length is key. The vest must cover the waistband of your trousers (in front and back)—if your shirt’s peeking under the vest, it’s a sign the vets is too short.
• Armholes: High and snug is the name of the game here. Poorly fitted armholes can cause bunching and make the vest look bulky—something you definitely want to avoid with the extra fabric of a double-breasted design.
• Chest Fit: A double-breasted vest should fit close to the chest, but not so tight that it pulls or lifts the lapel line. You want a smooth, even drape that flatters your build without restricting movement.

A tuxedo vest, like a tuxedo jacket, has a formal trim fabric (typically silk or satin) on the lapels, the buttons and the pocket trimmings. 

Traditionally this trim fabric would match across the jacket, the trousers and the bowtie.

The history of the tuxedo is all about minimalism - incorporating a maxium of two cloths (the main fabric and the trim).

A well-fitted vest does more than just sit nicely on your torso—it upgrades your whole outfit. Take it from this 5-star reviewer on TrustPilot, who needed a custom vest for an event: “The fabric is so high quality, people notice and compliment me every time I wear my AOS fits—I will never buy from a department store again.” 

If comfort is a concern, another reviewer, who picked up a wedding vest, shared that his “never feels tight or constraining and it hardly ever wrinkles, even when I pack it in a checked bag!” 

Whether you’re going with a classic single-breasted vest or something bolder like a double-breasted style, the right fit makes sure you look polished, confident, and effortlessly stylish.

Ready to step up your style with a perfectly fitted vest? Schedule a fitting today, and let’s find that perfect piece to jumpstart your capsule wardrobe. 👌

Yours in style,

Dan & AOS

Book the Capsule Wardrobe Experience.

I look forward to working with you!

Yours in style,

Dan Trepanier