Business and Financial Tools
Thailand VAT and Withholding Tax Calculator
Enter an amount, identify whether VAT is included, and set the VAT rate, withholding rate, and withholding base to see a complete payment breakdown.
Exact satang calculation
Enter the amount and tax rates
Choose what the entered amount represents. Rates can be changed to match your transaction.
Transparent breakdown
Tax calculation results
- Withholding base
- —
- Rounding
- Half up to 2 decimal places
Quick answer
How do I calculate Thai VAT and withholding tax together?
For an amount before VAT, multiply it by the VAT rate and add the tax. Calculate withholding from the applicable base, then subtract it from the VAT-included amount. This tool shows each component and lets you change the rates and withholding base.
How to use this tool
- Choose whether the entered figure is before VAT, VAT included, or for a withholding-only calculation.
- Enter the amount and rates, confirming the rates applicable to your transaction and documents.
- Choose the withholding base, review the breakdown, and export it to Print, Excel, PDF, or TXT if needed.
How the calculation works
The calculator converts money to integer satang and percentages to basis points. For a VAT-included amount, the pre-VAT value is amount × 100 ÷ (100 + VAT rate). Withholding can be calculated from either the pre-VAT or VAT-included amount. Every tax component uses round-half-up to 2 decimal places. The default 7% VAT rate reflects Revenue Department information verified on 31 July 2026; the applicable rate depends on the transaction and date.
Examples
| Example | Input | Expected result |
|---|---|---|
| THB 10,000 service before VAT | |
VAT THB 700, gross THB 10,700, withholding THB 300, net payment THB 10,400 |
| Extract VAT from a gross amount | |
Pre-VAT amount THB 1,000, VAT THB 70, net payment THB 1,070 |
| Withholding-only calculation | |
Withholding THB 50 and net payment THB 4,950 |
Limitations
- This is an arithmetic aid, not tax, legal, or accounting advice, and it cannot determine the correct rate or base for a specific transaction.
- Amounts must be non-negative and no more than THB 999,999,999,999.99; rates must be from 0 through 100% with no more than 2 decimals.
- The calculator rounds one tax amount half up to 2 decimals; it does not support per-line invoice rounding, multiple invoices, or accounting-system-specific rules.
- It does not produce tax filings, withholding certificates, tax invoices, or journal entries, and does not test exemptions.
Frequently asked questions
Does 7% VAT apply to every Thai transaction?
No. The 7% default reflects the general rate announced by the Revenue Department through 30 September 2026, but some transactions can be zero-rated, exempt, or subject to other rules. Confirm the transaction before relying on the result.
Should withholding be based on the amount before or including VAT?
The applicable base depends on the income type and transaction facts. The calculator defaults to the amount before VAT, a common case, while allowing the VAT-included amount for a user's document or scenario. It does not decide which base is legally correct.
Why can the result differ from an invoice by one satang?
Rounding order can differ: a system may round every line before adding them, or add first and round once. This page rounds each tax component half up to 2 decimal places, so compare the method with the source document.
Are the entered amounts or tax details stored?
No. Calculations and file generation run in your browser, and entered amounts and rates are not sent to the server.
References
- Thai Revenue Department — 7% VAT rate extended through 30 September 2026 Verified 2026-07-31
- Thai Revenue Department — 2026 Withholding Tax Training Guide Verified 2026-07-31
- Thai Revenue Department — Withholding under Section 3 Tredecim Verified 2026-07-31
Content and calculation method last reviewed: