What Size to Buy Him: Gift Sizing When You Don't Know His Size
The size label on the gift is the one thing you cannot guess from a photo. Here is how to buy with confidence anyway.
Last updated: October 2026
If you do not know his size, buy L. Across the Adam & Westcott catalog, M, L and XL are carried on essentially every top and outerwear piece, and L sits in the middle of that run, which makes it the safest letter when you have no label to work from. Better still, buy a gift with no size at all.
What size should I buy him if I don't know his size?
Buy L in tops and outerwear: it is stocked on nearly every piece and sits mid-run between S and 2XL, so it is the least likely letter to be wrong.
Different gift categories need completely different information, and some need none at all. This table shows which situation you are in.
| Gift type | What you need to know | The number | Adam & Westcott pick |
|---|---|---|---|
| Shirt | Letter size, or his chest in inches | 45.7 in chest at L |  CoreOps Button-Up Shirt, $49.99 |
| Vest or layer | Letter size only, worn over a shirt | 9 sizes, S to 6XL |  MULTI-POCKET CARGO VEST, $59.99 |
| Belt | His trouser waist, not his belt | 2 in ranges, 34 to 44 in |  Marenzo Brass Leather Belt, $39.99 |
| Trousers | Waist in inches, hardest to guess | Waist 30 to 40 |  SLIM STRETCH CASUAL PANTS, $29.99 |
| Watch, wallet, bag | Nothing at all | One size |  BOLD DIAL SPORT WATCH, $39.99 |
Why does the same letter fit differently?
Because a letter is a brand decision, not a measurement: two Adam & Westcott shirts both labelled L differ by 3.1 inches across the chest.
The 
CoreOps Button-Up Shirt is a 100% cotton true-to-size shirt measuring 42.5 in at S, 44.1 at M, 45.7 at L and 47.2 at XL, a 1.6 inch step per size. The 
LINEN CHEST POCKET SHIRT is cut oversized in 100% linen and measures 48.8 in at L, wider than the CoreOps shirt at 2XL. Read the chart on the product page, not the letter on the label.
What if he is between sizes, or you are guessing?
Size up, and pick a piece built to be worn loose: a vest forgives an inch of error where a fitted shirt does not.
SOFTSHELL FLEECE VESTWhich gifts need no size at all?
Watches, wallets, sunglasses and bags are all one size, so they remove the guess entirely.
-
BOLD DIAL SPORT WATCH, $39.99: quartz movement, auto date, luminous hands, 3 bar water resistance, five colorways. -
ELITE RFID LEATHER WALLET, $29.99: genuine cowhide, RFID protection, zip closure, dedicated coin pocket. -
UV400 SQUARE SUNGLASSES, $34.99: UV400 lenses, five colorways, a safe pick for any face shape. -
Vintage Cowhide Leather Travel Backpack, $139.99: full-grain cowhide, 20 to 35 L, 43 x 34 x 17 cm, fits a 15.6 inch laptop, 1.6 kg.
How do I size a belt as a gift?
Use his trouser waist, not a belt he already owns: Adam & Westcott belts are sold in 2 inch waist ranges, so one range covers two waist sizes.
The 
Marenzo Brass Leather Belt at $39.99 is 100% cowhide with a solid brass pin buckle, 1.5 inches wide, and runs five ranges: 34-36, 36-38, 38-40, 40-42 and 42-44 inches. Across all 64 belts in the belts collection, the 36, 38 and 40 inch waists are the most widely stocked. If he wears 36, buy 36-38.
Frequently asked questions
What size man's shirt should I buy as a gift?
Buy L. It is stocked on nearly every Adam & Westcott top, and on the CoreOps Button-Up Shirt L measures 45.7 inches at the chest, which covers most average builds.
Should I size up or down when buying a gift?
Size up. A shirt one size large can be worn open or layered, while a shirt one size small cannot be worn at all.
How do I find his size without asking?
Read the label on a shirt he wears often, then check that letter against the inch chart on the Adam & Westcott product page, because the same letter varies by up to 3.1 inches between styles.
What is the best gift if I know nothing about his size?
A watch, wallet, sunglasses or a bag, because all four are one size. The BOLD DIAL SPORT WATCH at $39.99 and the ELITE RFID LEATHER WALLET at $29.99 are the easiest places to start.
What size belt do I buy for a 36 inch waist?
The 36-38 inch range. Adam & Westcott belts are sold in 2 inch waist ranges, so it fits a 36 or 38 inch trouser waist.
More gifting help: our full gifts for men guide for 2026 sorts picks by price and recipient, the best gifts for men under $50 covers a tighter budget, and the Adam & Westcott size chart has chest measurements for every letter.
Shop the gifts that need no size
Watches, wallets, sunglasses, belts and bags, all one size. Browse the men's watches collection, or the full Adam & Westcott accessories collection.