Extending Tax Calculations

This topic discusses how to extend the tax calculation features of Global Payroll for Thailand.

Global Payroll for Thailand supports all of the tax allowances allowed by the Revenue Department available at the time of release. However, you may have to enter any new tax allowances that the Thailand Revenue Department announces after the release date.

Follow these steps to enter new tax calculation allowances:

  1. Add new fields on the Tax Allowance Declaration THA page (optional).

    Global Payroll for Thailand has two pages for tax allowance declaration: GPTH_TAX_ALLOW and GPTH_SS_TAX_ALLOW. This enables you to explicitly declare tax allowances.

  2. Modify the TAX AR ALLOWANCE array to retrieve information from the Tax Allowance Declaration Page (optional).

    The TAX AR ALLOWANCE array is used to retrieve tax allowance declaration data that is used by variables during the tax allowance calculation. If you create new fields for a tax allowance, you must create the corresponding supporting elements. Then, modify the TAX AR ALLOWANCE array to map any new fields to the new supporting elements.

  3. Create new tax allowance deduction elements.

    Create one deduction element for each new tax allowance, and add this tax allowance element into the TAX ALLOWANCE section.

    Specify the calculation logic of your new tax allowance that is based on the legal rule of the tax allowance. You may need use the following supporting elements:

    • Supporting elements that represent the declaration data on Tax Allowance Declaration page.

    • The total annual income variable, TAX VR TOTAL INC. Some tax allowances have limitations based on annual regular and irregular income.

    • The current taxable income amount variable, TAX VR TAXABLE AMT. It is equal to the difference between the TAX VR TOTAL INC variable and the total amount of tax allowances calculated before the current tax allowance.

  4. Add the current deduction element into the TAX AC ALLOW NM accumulator.

  5. Update the TAX VR TAXABLE AMT variable. Since this variable stores the current taxable income amount, you need to subtract the current tax allowance amount. You can create a post process formula to do this, such as the TAX FM ALL POST delivered by PeopleSoft.

  6. Add the new tax allowance into the TAX ALLOWANCE section. Pay close attention to the sequence number, since the Thailand Revenue Department specifies the detailed calculation sequence for each tax allowance. You need to add your new tax allowance to the correct position within the TAX ALLOWANCE section.

  7. Add the new tax allowance into the EG-COMMON element group.

  8. Update any related tax reports to include the new tax allowance.