You can generally bring back 1 liter of alcohol duty-free into the U.S. if you’re 21 or older. Anything above that must be declared, and you may owe duty or tax on the excess.

Practical takeaway

  • 1 liter per adult is the standard duty-free allowance.
  • You can usually bring more than 1 liter , but it must be declared and may be taxed.
  • Alcohol over 3.4 oz / 100 mL cannot go in carry-on unless it was bought after security in airport duty-free; otherwise it should go in checked luggage.
  • Large quantities can trigger extra questions if they look commercial rather than personal.

What this means from Japan

If you buy a bottle in Japan and want to bring it home, the safest simple rule is:

  1. Keep it within 1 liter if you want to avoid duty.
  1. If you buy more, declare it when entering the U.S..
  1. Pack bottles in checked baggage unless they were purchased airside at airport duty-free.

Common example

One traveler bringing back a single 750 mL bottle of whiskey would usually be within the duty-free limit. Two full-size bottles would likely exceed it and should be declared.

TL;DR

Up to 1 liter per adult is duty-free; more is allowed if declared, but you may pay tax/duty.