Accounting principles of costs
1. Costs are amounts reducing economic benefits, recorded at the time the transaction arises or shall be likely to arise in the future regardless of spending money or not.
2. Recording costs even which have not been at maturity but shall be likely to arise to ensure the principle of precaution and capital preservation. Costs and revenues set up by it must be recorded simultaneously on the principle of conformity. However, in some cases, conformity principles may conflict with the precautionary principle in accounting, accountants must be based on the nature and the accounting Standards to record transactions honestly and reasonably.
3. Each business can only apply one of two methods of inventory accounting: Perpetual inventory method or periodical inventory method. When a business selects an accounting method, then this method must be consistently applied at least in a financial year. In case business applies periodical inventory method: At end of accounting period, business must carry out inventory to determine value of goods stored at end of period.
4. Accountants must monitor details of expenses incurred in accordance with factors, wages, raw materials, purchase cost, depreciation of fixed assets...
5. Costs that are not considered as business income tax expense under the provisions of the tax Law but have full invoices and have been accounted in accordance with accounting policy shall not be recorded a decrease in accounting costs but shall only be adjusted in final business income tax declaration to increase the business income tax payable.
6. For accounts recording the cost without balance, at the end of the accounting period, accountants must transfer all expenses incurred during the period to determine income.

Source: Circualr 200