http://gocanada.about.com/od/tobaccoalcohol/a/smokesbooze.htm
アメリカからカナダに免税範囲を超えてUS25ドルのタバコを1カートン持ち込んだ場合の税金の計算例が載っています。これによれば、税額は、カナダドル換算valueの68%のようです。他国からでも同じことではないかと思うので載せておきます。
Every adult may bring one carton (200 cigarettes) or 50 cigars into Canada without paying any extra charges. Beyond this amount there are various taxes and fees that add up to a 68% surcharge. For this example, the person crossing the border has one carton of cigarettes which is duty free, and is bringing in an additional carton with a value of $US25.
Additional carton of cigarettes is valued at $US25
$US25 X 1.22 = $CAD30.50 (taxable amount)
$CAD30.50 X 68% = $CAD20.74
The person bringing in the cigarettes will need to pay the $CAD20.74 to bring $US25 worth of tobacco into Canada. The maximum tobacco you can bring into Canada without an importer’s license, including the duty free volume, is 2,000 cigarettes (10 cartons) or 500 cigars.