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Update criteria for year 2026 (P. N. D.91)
Tax Refund / Additional Tax Paid Calculator
The Tax Refund / Additional Tax Paid Calculator estimates an income, tax or statutory-cost estimate for the figures entered from the income, employment or business status, relevant period, allowances and current thresholds shown on the page. Replace the example values with your own tax refund additional tax paid figures and recalculate after changing an assumption. Treat it as a planning estimate and independently verify the current rule or provider terms.
Fill in the income, deductions, and taxes withheld throughout the year. The system will tell you how much tax you'll get back or have to pay extra.
Fill in tax information for the entire year
Calculation results
How to calculate tax refund / additional tax paid
Basic formula: Net amount = Tax payable − Accumulated withholding tax
- If the result is delete → Yes. tax refund
- If the result is plus → Must Pay more
- if the result zero → No need to do anything additional.
Tax payable is calculated based on net income (income − expenses − deductions) based on a stepped rate. 5–35%
Formula used for calculation
Tax refund = accumulated withholding tax for the whole year − tax actually paid
If the result is a positive number It shows that you received a tax refund. The Revenue Department will refund the money within the period. 15–30 days
Calculation example
Example 1: Salary employee 50,000 baht, married, has 1 children.
- Total annual income = 50,000 × 12 = 600,000 baht
- Lump sum cost = 600,000 × 50% = 300,000 baht
- Total deductible = 60,000 + 60,000 + 30,000 = 150,000 baht
- net income = 600,000 − 300,000 − 150,000 = 150,000 baht
- Tax payable = 0 baht (income 150,000 is in the first stage 0%)
- Withholding tax throughout the year = 1,500 × 12 = 18,000 baht
- tax refund = 18,000 − 0 = 18,000 baht
summarize
A tax rebate occurs when the tax withheld throughout the year is more than the tax actually due. Eligible persons must submit a form. P. N. D.91 within the deadline. The Revenue Department's e-Filing system makes it convenient to submit.
refer: Revenue Department: Tax refund system [Update 2026]
Frequently asked questions
What is a tax refund?
By what date must the annual tax return be filed?
Where can I find the accumulated withholding tax for the entire year?
If I have to pay additional tax, will there be a penalty?
How do people with many types of income use it?
Learn more from our article.
English calculator guide
How to use the Tax Refund / Additional Tax Paid Calculator
Use this page to test a specific tax refund additional tax paid scenario. Enter your own values in the calculator above, review the units beside each field, and recalculate after changing an assumption. The result updates the tax refund / additional tax paid estimate instead of relying on a generic example.
- Build a baseline tax refund additional tax paid case with figures that match your situation.
- Run a second tax refund additional tax paid case after changing the rate, period, quantity or other key assumption.
- Record the difference between the two tax refund additional tax paid results and the input responsible for it.
Inputs for the tax refund additional tax paid estimate
For this tax refund additional tax paid calculation, check the income, employment or business status, relevant period, allowances and current thresholds shown on the page. The result is designed to show an income, tax or statutory-cost estimate for the figures entered, not a guaranteed provider price or official decision.
How the tax refund additional tax paid result is calculated
The calculator applies the displayed statutory rates, thresholds and allowances to the figures you enter. Reusing the same tax refund additional tax paid inputs will produce the same estimate, which makes the page suitable for controlled scenario comparisons.
Checks for a tax refund additional tax paid decision
Check the effective date and confirm current rules with the relevant Thai authority or a qualified adviser. For tax refund additional tax paid, Treat the result as an estimate for planning. Tax rules, eligibility and deduction limits can depend on the tax year and your evidence, so compare the result with current Revenue Department guidance or a qualified adviser. Because this calculation can affect an important financial, legal or health decision, independently verify the inputs and current rules before relying on the result.
- Language QA
- Terminology, numeric values and calculator controls checked
- Calculator scope
- Tax and statutory rate
- Last English review
- 26 July 2026