I always wear a size L tank top or t-shirt, but they run smaller than I usually expect. My advice is to order a size up unless you want a really tight fit.
AM Fitted T Shirt 3 Pack for Men's Clothing - T-Shirts & Tanks
46 Review
Carhartt Workwear XXXXX-Large Men's T-Shirt β Original Clothing for T-Shirts & Tanks
34 Review
Ultimate Comfort: Discover the Comfort Colors Sleeve 6014 - X Large Men's Clothing, T-Shirts & Tanks
40 Review
Next Level Premium Fitted N6210: High-Quality Men's Clothing & Essential T-Shirts + Tanks Collection
39 Review