Traveling abroad, tourists tend to buy large amounts of goods and bring them back to their home country or sometimes to the next country they’re visiting. This is especially true with brand-name products, some of which are subject to tax.

The import tax calculation on products is divided into three parts:
1. Import duty = product price x import duty rate;
2. VAT = (product price + import duty) x VAT rate 7%;
3. Total taxes to be paid = import duties + VAT.

For example, if you buy a brand-name bag for 100,000 baht from abroad and bring it to Thailand, even for personal use, since the value is over 20,000 baht, you have to pay tax, as follows:

1. Calculate import duty = product price (100,000) x import duty rate (20%); 
    Import duty = 20,000 baht.

2. Calculate VAT = [Product price (100,000) + Import duty (20,000)] x VAT 7%;
    The VAT on this bag is 8,400 baht.

​​​​​​3. The total tax to be paid is import duty (20,000) + VAT (8,400) = 28,400 baht.

Source : bangkokbiznews