What Size Trousers Should I Buy? A Men's Waist and Letter Size Guide (2026)

Two sizing systems sit side by side in one collection, and knowing which a listing uses is the whole job.

Last updated: October 2026

Buy by the number whenever you can. Of the 48 men's trousers active at Adam & Westcott, 14 are sold by waist in inches, covering 28 in to 44 in, and the other 34 are sold by letter, from XXS up to 8XL. Measure your waist once, then check which of the two the product page asks for.

Are Adam & Westcott trousers sized by waist inches or by letter?

Both, split 14 to 34. The waist-sized pairs name a number you can measure against; the 34 letter-sized pairs publish no inch equivalent anywhere, so a letter there is a fit description rather than a measurement.

Sizing system	How many pairs	Range	Best for	A&W pick
Waist in inches	14 of 48	28 in to 44 in	Chinos, cords and smart trousers that sit at the waist	Slim Cotton Chinos, $44.99
Letter size	34 of 48	XXS to 8XL	Cargos and drawcord trousers with give in the waistband	Wide-Leg Cargo Pants, $59.98

What waist sizes can I actually get?

Five waists are carried on all 14 waist-sized pairs: 30 in, 32 in, 34 in, 36 in and 38 in. Outside that band, coverage narrows quickly.

• 40 in sits on 13 of the 14.
• 28 in and 29 in sit on 5 each.
• 42 in sits on 6, and 44 in on only 2.
• Odd inches such as 31, 33 and 35 sit on 4 pairs or fewer.

If you measure 44 in, the two pairs that reach you are Cotton Twill Trousers at $42.77 and Rugged Eight-Pocket Trousers at $39.98.

Which pair gets closest to my exact waist?

The Slim Cotton Chinos run 14 consecutive single-inch sizes, 29 in to 42 in, the finest ladder in the collection.

Three more get you within an inch:

Our best seller, the Slim Stretch Casual Pants at $29.99, is sold in even waists only, 30 in to 40 in. On an odd measurement such as 33 in, the stretch in the fabric means sizing down to 32 in is usually the better call than going up to 34 in.

What letter size should I buy when there is no waist number?

M, L and XL are carried on all 34 letter-sized pairs, so the middle is never the problem. The ends are.

• S sits on 28 of 34, and 2XL on 28 of 34.
• 3XL drops to 18, 4XL to 10, 5XL to 7 and 6XL to 6.
• XS sits on 7 pairs, XXS on only 2.

Above 6XL, one pair goes further: Northway Wide-Leg Cargo Pants at $37.99 runs to 8XL across ten steps. At the other end, Panel Cargo Trousers at $39.99 and Belted Outdoor Trousers at $49.98 are the two that open at XXS.

Nearly all of them carry an elastic, drawcord or drawstring waist, which is why a letter is enough. Between two letters, the drawcord takes up the difference, so take the smaller one.

Which belt size goes with my trouser waist?

Adam & Westcott belts are sold in two-inch waist ranges, so match the range that contains your trouser waist. At 30 in or 32 in that means the Belmont Signature Belt at $59.98, which runs seven ranges from 30 to 32 up to 42 to 44. The Marenzo Brass Leather Belt at $39.99 and the Classic Cowhide Belt at $54.99 both open at 34 to 36, so a 30 in or 32 in waist is below their smallest range.

Frequently asked questions

Where do I measure for trouser waist size?
Around your natural waist, where the waistband will sit, tape flat and level. Use that figure directly on the 14 waist-sized pairs, which run 28 in to 44 in.

Should I size up or down between two waist sizes?
On the Slim Stretch Casual Pants, which are sold in even waists from 30 in to 40 in, size down, because the stretch gives you the extra. On a rigid cotton twill, size up.

Do any Adam & Westcott trousers publish a letter-to-inch conversion?
No. None of the 34 letter-sized pairs publishes a waist in inches, so buy a waist-sized pair when you need an exact number.

What is the widest size range here?
The Northway Wide-Leg Cargo Pants at $37.99, ten letter steps up to 8XL, and the Wide-Leg Cargo Pants at $59.98, XS to 6XL in ten steps.

How much do men's trousers cost at Adam & Westcott?
The 48 active pairs run from $29.99 to $74.98. The waist-sized pairs start at $29.99 and the letter-sized pairs start at $32.99.

More on this collection: our guide to men's trouser fits covers the shapes rather than the sizes, three ways to wear the Slim Stretch Casual Pants styles our best seller, and our belt size guide goes deeper on matching a belt to a waist.