Enforcement Rules of the Income Tax Act Article 48
Depreciation methods for fixed assets stated in Article 51 of the Act are as follows:1. Where the average method is adopted, the balance amount of the fixed asset cost minus the salvage value equally shared according to the years of durability prescribed in the Table of the Service Life of Fixed Assets shall be used to calculate the depreciation amount for each period.2. Where the fixed-rate progressive decrease method is adopted, the balance amount order of the depreciation amount for each period subtracted from fixed assets for each period shall be used as the basis for calculating depreciation for each time/period, and a fixed percentage shall be used to calculate the depreciation amount.3. Where the sum-of-years`- digits method is adopted, the balance amount of the fixed asset cost minus the salvage value multiplied by a decreasing fraction where the denominator is the sum of the years` digits of the service life and the numerator is the digit of the year of use in a reverse order shall be used to calculate the depreciation amount for each period. However, the years of the service life shall not be shorter than the years of durability prescribed in the Table of the Service Life of Fixed Assets.4. Where the production quantity method is adopted, the balance amount of the fixed asset cost minus the salvage value shall be divided by the estimated total production quantity to calculate the depreciation amount per unit of production, and then multiplied by the actual production quantity realized in each period to calculate the depreciation amount for each period. However, the period of the estimated total production quantity shall not be shorter than the years of durability prescribed in the Table of the Service Life of Fixed Assets.5. Where the working time method is adopted, the balance amount of the fixed asset cost minus the salvage value shall be divided by the estimated total working time to calculate the depreciation amount to be assumed in each unit of working time, then multiplied by the actual working time used in each period to calculate the depreciation amount for each period. However, the estimated total working time shall not be shorter than the years of durability prescribed in the Table of the Service Life of Fixed Assets.
中文原文 所得稅法施行細則第48條
本法第五十一條所定固定資產之折舊方法如下：
一、採平均法者，以固定資產成本減除殘值後之餘額，按固定資產耐用年數表規定之耐用年數平均分攤，計算每期折舊額。
二、採定率遞減法者，以固定資產每期減除該期折舊額後之餘額順序作為各次期計算折舊之基數，而以一定比率計算各期折舊額。
三、採年數合計法者，以固定資產成本減除殘值後之餘額，乘以一遞減之分數，其分母為使用年數之合計數，分子則為各使用年次之相反順序，計算各期折舊額。
但使用年數，不得短於固定資產耐用年數表規定之耐用年數。
四、採生產數量法者，以固定資產成本減除殘值後之餘額，除以估計之總生產量為每一單位產量應負擔之折舊額，再乘以各期實際之生產量，計算各期折舊額。
但估計總生產量之期間，不得短於固定資產耐用年數表規定之耐用年數。
五、採工作時間法者，以固定資產成本減除殘值後之餘額，除以估計之全部使用時間為每一單位工作時間應負擔之折舊額，再乘以各期實際使用之工作總時間，為各該期之折舊額。
但估計之全部使用時間，不得短於固定資產耐用年數表規定之耐用年數。
一、採平均法者，以固定資產成本減除殘值後之餘額，按固定資產耐用年數表規定之耐用年數平均分攤，計算每期折舊額。
二、採定率遞減法者，以固定資產每期減除該期折舊額後之餘額順序作為各次期計算折舊之基數，而以一定比率計算各期折舊額。
三、採年數合計法者，以固定資產成本減除殘值後之餘額，乘以一遞減之分數，其分母為使用年數之合計數，分子則為各使用年次之相反順序，計算各期折舊額。
但使用年數，不得短於固定資產耐用年數表規定之耐用年數。
四、採生產數量法者，以固定資產成本減除殘值後之餘額，除以估計之總生產量為每一單位產量應負擔之折舊額，再乘以各期實際之生產量，計算各期折舊額。
但估計總生產量之期間，不得短於固定資產耐用年數表規定之耐用年數。
五、採工作時間法者，以固定資產成本減除殘值後之餘額，除以估計之全部使用時間為每一單位工作時間應負擔之折舊額，再乘以各期實際使用之工作總時間，為各該期之折舊額。
但估計之全部使用時間，不得短於固定資產耐用年數表規定之耐用年數。