Except as otherwise prescribed in Section 2 of this chapter, business entities shall calculate the output tax based on the relevant sales amounts of goods and services, in accordance with the applicable tax rates prescribed in Article 7 or 10 and round to the nearest New Taiwan Dollar.
The output tax is defined as the amount of business tax to be collected in accordance with this Act by the business entity at the time of selling goods or services.

The amount of business tax payable or overpaid by a business entity will be the difference between the output tax in a tax period and the input tax in the same period.
The amount of business tax returned by a business entity to a purchaser due to sales return of goods or rebates allowed shall be deducted from output tax in the tax period when the return or rebate occurs. The amount of business tax received by a business entity due to the business entity's return of purchased goods, or due to an allowance on purchased goods, shall be deducted from the amount of input tax in the tax period when such return of goods or allowance occurs.
The input tax is defined as the business tax paid by a business entity in accordance with the act at the time of purchasing goods or services.

If a business entity sells its used passenger car or motorcycle purchased from a person who is not required to file a tax computation under this section, such business entity may calculate the input tax by the following formula:
Purchased cost of the used
passenger car or motorcycle
Input tax = －－－－－－－－－－－－－ × Applicable collection rate
1 + applicable collection rate
The business entity shall report the input tax as referred to in the preceding paragraph in order to deduct it from the output tax of the used passenger car or motorcycle in the same period in which it reports the sales amount of such passenger car or motorcycle. However, if the input tax of the used passenger car or motorcycle is higher than output tax of the aforesaid vehicle, the excess portion shall not be deducted.
When the business entity files the input tax as referred to in the first paragraph above, it shall provide relevant documents concerning the purchase of the aforesaid used passenger car or motorcycle.
The preceding paragraphs shall be applicable to cases not currently being assessed or pending final decision at the effective date of this amended article.

The sales amount prescribed in Article 14 means the total consideration received from the sale of goods or services, including any charges collected by a business entity besides the sales amount of the goods or services sold, but not including the business tax payable for that sale.
If the goods referred to in the preceding paragraph are subject to the commodity tax, the tobacco and alcohol tax, or the health and welfare surcharge on tobacco, the sales amount shall include the amount of the commodity tax, the tobacco and alcohol tax, or the health and welfare surcharge on tobacco.

In the event that a business entity sells goods or services at a price significantly lower than the market price with no proper reason, the competent tax authority may determine the sales amount based on the market price.

The sales amount of an international transport enterprise transporting outbound cargo or passengers from within the territory of the R.O.C. shall be calculated as follows:
1. Marine transport enterprise: total ticket fares or freight charges for outbound passengers or cargo accepted for transportation from within the territory of the R.O.C.
2. Air transport enterprise:
(a) passenger transportation: ticket fares from the point of embarkation within the territory of the R.O.C. to first-leg stations outside the territory of the R.O.C.;
(b) cargo transportation: freight charges for the entire trip for the cargo accepted for transportation. However, where an international air transport enterprise transships its outbound cargo en route to an aircraft of another international air transport enterprise due to route restrictions or other reasons, its freight shall be calculated upon the charges actually attributable to the portion made by the first enterprise.
First-leg stations outside the territory of the R.O.C., as provided in Item 1 of Subparagraph 2 of the preceding paragraph, shall be prescribed by the MOF.

In any of the following events, a business entity may not deduct the input tax from the output tax:
1. Where the supporting documents, as set out in Article 33 herein, for purchased goods or services are not obtained or kept in the manner required.
2. The goods or services purchased are not for the use of principal and ancillary business operation. However, this requirement does not apply to purchases made for the support of national defense, provision of morale services to the troops, or contribution to the government.
3. Goods or services for social relations purposes.
4. Goods or services rewarded to individual employees.
5. Passenger cars for personal use.
Business entities engaging solely in the business of tax-exempt goods or services as provided in Paragraph 1, Article 8 herein may not apply for refund of the input tax.
When a business entity is prohibited from deducting a certain part of the input tax from the output tax because it engages on a concurrent basis in the business of tax-exempt goods or services provided in Paragraph 1, Article 8 herein, or due to other provisions of this Act, the ratio and calculation method related to the non-deductible amount shall be prescribed by the MOF.

The business tax on imported goods shall be calculated based on the total sum of amount of the customs taxable value and import tariffs at the tax rate provided in Article 10.
If the above-mentioned goods are subject to the commodity tax, the tobacco and alcohol tax, or the health and welfare surcharge on tobacco, the business tax shall be calculated based on the total amount prescribed in the preceding paragraph plus the commodity tax, the tobacco and alcohol tax, or the health and welfare surcharge on tobacco.