How many BTUs do I need in a portable grill?

BTUs alone don't determine cooking power, the cooking-area-to-BTU ratio matters more. A focused single burner around 8,500-11,000 BTU (like the Weber Q1200 or Megamaster) can sear as well as a sprawling 20,000+ BTU two-burner because heat is concentrated over a smaller grate. For groups of 4+, look for 20,000 BTU and dual burners so you can run two-zone cooking.