What size toiletry bag do I need for carry-on travel?

For TSA-compliant 3-1-1 liquids only, a small quart-sized bag is sufficient. For full-size bottles on longer trips, look for capacity in the 3–5 liter range. Verified-purchase reviewers note that oversized bags eat carry-on volume quickly, so most one-bag travelers prefer medium over large unless they pack a hair dryer or extensive skincare.