Most US domestic airlines don’t have weight limits for carry-ons: If you can hoist it into the overhead bin, you’re okay. However, some low-cost carriers and international airlines may have weight limits for carry-on bags ranging from 15 lbs (Qantas, Emirates) to 17 lbs (LATAM) to 22 lbs (Air Canada, Caribbean Airways, etc) and heavier. Just check the individual carrier before you fly.