Step-by-Step Guide: VAT and WHT Calculation Method for Thailand

This tutorial provides a clear breakdown of how to calculate VAT (Value-Added Tax) and WHT (Withholding Tax) in compliance with Thai tax laws. It also includes how discounts are handled in the calculations.

1. VAT Calculation (7%)

VAT is calculated as 7% of the price before VAT. To determine the VAT, follow these steps:

  • Step 1.1: Calculate Price Before VAT
    Use the formula: ฿Price Before VAT = ฿Total Amount ÷ (1 + VAT Rate)

    Example: ฿292,008.27 = ฿312,448.85 ÷ 1.07

  • Step 1.2: Calculate VAT Amount
    Use the formula: ฿VAT Amount = ฿Price Before VAT × VAT Rate

    Example: ฿20,440.58 = ฿292,008.27 × 0.07

2. WHT Calculation (3%)

WHT is based on the price before VAT. The WHT rate depends on the type of service, and for services in Thailand, the standard rate is 3%.

  • Step 2.1: Calculate WHT Amount
    Use the formula: ฿WHT Amount = ฿Price Before VAT × WHT Rate

    Example: ฿8,760.25 = ฿292,008.27 × 0.03

3. Grand Total Net

This is the final amount after deducting WHT from the total payment.

  • Step 3.1: Calculate Grand Total Net
    Use the formula: ฿Grand Total Net = ฿Total Amount - ฿WHT Amount

    Example: ฿303,688.60 = ฿312,448.85 - ฿8,760.25

4. Handling Discounts

When a discount is applied, it must be deducted before calculating VAT. Here’s how to handle it:

  • Step 4.1: Adjust Total with Discount
    ฿Adjusted Total = ฿Original Total - ฿Discount Amount

    Example: ฿300,000.00 = ฿312,448.85 - ฿12,448.85

  • Step 4.2: Calculate VAT on Adjusted Total
    ฿Price Before VAT = ฿Adjusted Total ÷ (1 + VAT Rate)
    ฿VAT Amount = ฿Price Before VAT × VAT Rate

    Example: ฿280,373.83 = ฿300,000.00 ÷ 1.07 ฿19,626.17 = ฿280,373.83 × 0.07

  • Step 4.3: Calculate WHT on Price Before VAT
    ฿WHT Amount = ฿Price Before VAT × WHT Rate

    Example: ฿8,411.21 = ฿280,373.83 × 0.03

  • Step 4.4: Calculate Grand Total Net with Discount
    ฿Grand Total Net = ฿Adjusted Total - ฿WHT Amount

    Example: ฿291,588.79 = ฿300,000.00 - ฿8,411.21

Summary of Key Formulas

Component Formula
Price Before VAT ฿Total Amount ÷ (1 + VAT Rate)
VAT Amount ฿Price Before VAT × VAT Rate
WHT Amount ฿Price Before VAT × WHT Rate
Grand Total Net ฿Total Amount - ฿WHT Amount
Adjusted Total (Discount) ฿Original Total - ฿Discount Amount

This method ensures accurate calculations for VAT, WHT, and any applied discounts, while complying with Thai tax regulations.

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