WHAT YOU CAN BRING BACK

For U.S. Citizens returning to the United States:
U.S. residents returning to the United States after 48 hours can take back $800 U.S. worth of merchandise, duty free, every 30 days.

This may include: Members of a family travelling together may combine their personal exemptions.

After a visit of less than 48 hours, or if the $800 allowance or part of it has been used within the previous 30 days, an exemption of $200 U.S. is allowed (may not be combined by family members), including 150 mL (4 ounces) of alcohol, 150 mL of perfume and no more than 50 cigarettes or 10 cigars, not of Cuban origin. Articles brought back into the U.S. as part of an exemption must be for personal or household use. They must be brought with the person and properly declared. They must not include prohibited or restricted items.

Duty charged varies according to the country the article was made in and the type of article. More information about entering or re-entering the U.S. is available through U.S. Customs.

WHAT YOU CAN BRING INTO CANADA

For U.S. Citizens coming into Canada:
Alcoholic Beverages
Visitors arriving in Ontario who are 19 years of age or older may import, duty and tax free, for personal use, either 1.5 litres (52.7 ounces) of wine or 1.14 litres (40 ounces) of liquor or spirits; or 24 x 355 mL (12 ounce) cans or bottles of beer, ale, or their equivalent. Visitors can import more alcoholic beverages (up to 45 litres or 11.9 U.S. gallons), if they are willing to pay the Ontario fees and taxes in addition to the duties that apply.

Tobacco Products
Visitors arriving in Ontario who are 19 years of age or older may import, duty and tax-free:
If visitors bring in more tobacco products, they will have to pay the Ontario taxes and duties that apply, as specified by the Canada Border Services Agency (CBSA).
For Canadian Citizens returning to Canada:

The CBSA wishes to remind all travellers that changes were recently made to the limits of personal exemptions. Since June 1, 2012, the new limits of personal exemptions are:

After being away for: You can bring back goods, tax and duty free, worth up to:

Note that there are no personal exemptions for stays of less than 24 hours.

Alcoholic beverages and tobacco products may be included in your 48-hour or seven-day exemption, provided you are of legal age, but certain restrictions apply.

Exemption chart on alcohol and tobacco

Only one of the following amounts of alcoholic beverages may be imported free of duty and taxes (when stays are more than 48 hours):

You must be of legal age in the province of importation.

The following amounts of tobacco products may be imported free of duty and taxes (when stays are more than 48 hours):