How to Choose Your Size — A Fit Guide With Less Guesswork

Clarity over clutter.

The biggest uncertainty in online shopping is rarely the color or the design. More often, it’s a simpler question: “Will this actually fit me well?”

Good clothing is never defined by appearance alone. What matters just as much is how a piece sits on the body — where the shoulder line falls, whether the shirt pulls at the chest, whether the trousers feel narrow through the thigh. MONSEN’s size guidance exists to reduce that uncertainty.

The simplest way to think about it: your usual size is the starting point; the garment’s intended fit is the real decision-making tool.

The most accurate method: measure a garment you already like

Body measurements help, but the most reliable method for online shopping is often to measure a garment you already own and wear well. Two people with similar chest measurements may still prefer very different fits. A garment you already trust tells you what feels right on you.

• Shirts — shoulder width, chest width, sleeve length, overall length
• Blazers — shoulder width, chest width, sleeve length, overall length
• Trousers — waist width, thigh width, rise, hem width, overall length

You don’t need to match every number. If a shirt you like has a 55 cm chest and a new one measures 53 cm, expect a neater fit; 57 cm will feel more relaxed. Use the numbers to predict how the fit will behave, not as the final answer.

Shirts — start with the shoulder

A shirt looks simple, but it shapes the whole outfit. Instead of the neck or the size label, look in this order:

• Shoulder — a seam set too far inside feels tight; too far beyond looks loose. Under a blazer it should feel controlled, not stiff.
• Chest and body — no pulling at the buttons, but not so much room that it bulks under a blazer. The tightest fit is not the best one.
• Sleeve length — to the wrist. With tailoring, a little cuff showing past the blazer sleeve is the safest balance.
• Collar — secure without pinching, and not gapping. This matters more with a tie.

Blazers — the shoulder comes first

A blazer depends on upper-body balance more than anything else. A shirt can be styled; trousers can be adjusted. But when the shoulder is wrong, the whole garment feels wrong.

The shoulder line should follow the natural end of your shoulder without cutting inward or hanging outward. A strong X-shaped tension line around the button usually means it’s too small through the body.

MONSEN tailoring favors softer structure over stiffness. So once the shoulder sits properly, a little ease through the chest or waist often makes the blazer feel more natural and wearable all day.

Knitwear — judge by layering, not just closeness

Knitwear is often judged too quickly by how slim it looks. The most useful knit wears cleanly on its own and layers easily when needed.

• On its own — not tight through the chest, but not shapeless either. A clean line with a little ease.
• Over a shirt — slightly more room so the neck, shoulder, and armhole don’t feel crowded.
• Under a blazer — thickness matters as much as size. Rather than sizing up, choose a finer gauge to avoid bulk.

Trousers — the waist is not the whole story

Trousers are usually chosen by waist first, but the real experience depends on rise, thigh, hip, and overall line.

• Waist — secure without strain.
• Thigh — the most overlooked area. Too tight looks less polished and feels worse when sitting or walking. A little ease often creates a cleaner line.
• Rise — the best rise is the one you barely notice all day.

The ideal MONSEN trouser line isn’t skinny — it’s a controlled straight or softly tailored shape that works across office, commute, and everyday wear.

Outerwear — judged by what you wear underneath

For a coat, the key question isn’t only whether it fits on its own — it’s whether it still works once your usual layers are underneath. A shirt-only layer needs different room than a knit or blazer underneath. Outerwear usually benefits from a little more room, but that room should still look intentional. Oversized doesn’t automatically mean better layered.

When the size feels uncertain, what to prioritize

• Shirts — choose the size that doesn’t pull through the shoulder or chest. Ease beats tension.
• Blazers — the shoulder first. If it’s wrong, the rest rarely feels right.
• Knitwear — neat for standalone wear, a little more room for layering.
• Trousers — between a looser waist and a tight thigh, choose comfort through the thigh and hip. The waist is easier to adjust.
• Outerwear — leave room to layer, but don’t let the shoulder drop so far it loses structure.

A tighter fit is not always a better fit.

A garment that’s too small creates tension and stiffness — not cleaner lines. A better fit lets the garment sit well, move well, and hold its shape naturally. At MONSEN, good fit is about balance, not compression.

Four things to read alongside the size chart

• Fit description — words like slim, regular, relaxed, or straight explain how it’s meant to sit.
• Fabric behavior — stretch, drape, and thickness change the feel at the same measurements.
• Styling intention — standalone or layered changes how the size should be read.
• Product imagery — model photos are information; front, side, and seated views show length and ease.

If this is your first MONSEN purchase

Begin with a foundational item rather than the most experimental one — an ivory shirt, a deep navy blazer, charcoal or stone trousers, a knit that layers easily. These are easy to understand, easy to compare against what you own, and easy to build around. The goal of a first purchase is to establish a fit reference you can return to.

Before ordering, ask a few calm questions. Will the shirt shoulder sit naturally? Will the blazer button without pulling? Will the trousers feel comfortable through the thigh and rise? Can the knit work alone and as a layer? And most important — will this make the day easier to wear?

MONSEN — Size Guidance   -> journal