Withholding tax & VAT calculator
Thai withholding tax (WHT) is calculated on your service fee before VAT, then subtracted from the total invoice amount. For example: a 10,000 baht fee with 3% WHT means 300 baht withheld; if VAT-registered, add 7% VAT (700 baht) to get 10,700 baht invoiced. Your client pays 10,400 baht (the total minus WHT). This calculator works both ways: forward from your fee, or reverse — if a client withheld 300 baht at 3%, your gross fee was 10,000 baht and they transferred 9,700 baht. WHT rates range 1–15% depending on income type (service fees, rent, professional, etc.), per Thai Revenue Department rules. BillsOS formats and computes these figures; this is not tax advice.
Work out withholding tax and VAT both ways — forward (from your fee) and reverse (a client withheld 3% = THB X, what was the gross?).
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Worked scenarios
Forward — ฿10,000 fee, 3% WHT + 7% VAT
Fee 10,000 · VAT 700 · invoiced 10,700 · WHT 300 (on the pre-VAT fee) · client pays 10,400 baht.
Reverse — client withheld ฿300 at 3%
Gross fee = 300 ÷ 0.03 = 10,000 baht; net transferred = 9,700 baht (no VAT case).
Rates follow Revenue Department income types (services often 3%, rent 5%, etc.) · see withholding tax rates.
BillsOS only formats and computes documents for you. This is general information, not tax advice — please confirm with the Revenue Department or your accountant.