Duty is based on the value of the item you ordered in Canadian dollars. The sender in the United States will have to attach a written declaration, called Form E14, to the package listing values and descriptions of the items. The package will go to the Canada Border Services Agency, which will assess it and calculate appropriate duty fees.
According to Canada Border Services Agency, items worth less than $20 will not be charged duty, with the exception of alcohol, tobacco products, some publications, and goods ordered from a Canadian retailer but shipped from the United States. When importing items from the United States, things made in the United States or Mexico are not charged duty fees under the North American Free Trade Agreement.
The Canada Border Services Agency states that for items worth more than $20 or that don't qualify for the $20 exemption, duty is calculated based on the total value of the item. Though goods made in the United States and Mexico are exempt, an item sent from the United States is not necessarily made there. Anything made elsewhere will be charged duty. The duty fee will vary depending on the type of item and where it was made. An additional duty, called an excise duty, may be charged on luxury items.
GST, or HST if applicable, will be charged on most items imported from the United States if it has not already been paid. PST will also be collected if applicable. The amount charged will depend on the province you live in. If applicable, tobacco tax will also be collected at the rate your province charges.
When you go to pick up your package, Canada Post will collect any duty and taxes before they release the package to you. If duty or taxes are owed, they will also charge an additional fee of $5 or $8, depending on whether the item was in regular mail or express mail.
If you disagree with the duty or taxes charged, you can refuse to accept the package. It will be returned to the Canada Border Services Agency, where it will be reassessed and returned to Canada Post. If you have already paid the fees and accepted the item, you can fill out the Informal Adjustment Request form on the back of Form E14 and send it to the address listed on the form along with proof of the items' value. Any refund you are entitled to should be sent to you within 10 days.