Income tax calculator: the tax you owe, your deductions, and the RMF and ThaiESG you can still buy

The 2026 personal income tax calculator estimates your tax for the year from your income and deductions, then tells you how much more RMF and ThaiESG you can buy for a deduction. It is the "Tax deductions" topic of the financial planning page, so it shares the same customer details.

The tax rates and deduction caps are rules built into the tool, and the figures come from what you enter. Fields labelled "From client details", such as salary, marital status, child allowance and PVD contribution rate, are taken from the customer details bar at the top, and every field can be changed.

Income

The income section starts with type 40(1) income: monthly salary (multiplied by 12 for the year), extra income such as bonuses and overtime, severance pay (gratuity), severance pay on termination, which is tax-exempt up to the last 400 days' wages and no more than THB 600,000, and withholding tax. Press "Add or remove income items" to add types 40(2) to 40(8), such as commission, rent, dividends and interest, or income from online selling. The section ends with a preliminary summary of assessable income after expense deductions.

Deductions it supports

• Basic: personal THB 60,000, a spouse with no income, children, parents you support, disabled or incapacitated people you support at THB 60,000 each, prenatal care and childbirth at actual cost up to THB 60,000 per pregnancy, and health insurance for your parents up to THB 15,000
• Insurance: social security up to THB 10,500, life insurance at the amount paid up to THB 100,000, and health insurance up to THB 25,000, with life and health insurance together capped at THB 100,000
• Savings and investment: RMF up to 30% of income, pension insurance up to 15% and THB 200,000, PVD up to 15% of wages, GPF, and the National Savings Fund (NSF) up to THB 30,000, with the whole group capped at THB 500,000. ThaiESG is up to 30% of income and THB 300,000, separate from the retirement group, and there is a field for LTF switched to Thai ESGX
• Donations and other: home loan interest up to THB 100,000, solar rooftop installation up to THB 200,000, artwork purchases, investment in social enterprises, general donations, donations to education, sports, social causes and public hospitals deducted at 2 times, and donations to political parties up to THB 10,000

Each field shows its cap under its name. The "Max" button fills in the full cap, entering more than allowed shows "Over the limit", and the quick summary box shows what counts after the limits.

Reading the results

• The headline shows the tax to pay. If you have entered withholding tax, it shows the tax still to pay or the refund instead. The next line shows how much more you can deduct with RMF and ThaiESG
• Tax brackets shows the top bracket your net income reaches and your average tax rate on net income
• "If you invest in RMF + ThaiESG" shows the total to invest and the tax saved, or the refund. It uses your remaining RMF room first, then ThaiESG, and goes no further than the amount that brings net income down to THB 150,000, the tax-free bracket
• The tax rate table works step by step: annual assessable income, less expenses by income type, less deductions, gives net income; tax is calculated at progressive rates, then withholding tax and the dividend tax credit are deducted to give the net tax payable

The brackets used: net income of 0 to THB 150,000 is exempt, 150,001 to 300,000 is 5%, 300,001 to 500,000 is 10%, 500,001 to 750,000 is 15%, 750,001 to 1,000,000 is 20%, 1,000,001 to 2,000,000 is 25%, 2,000,001 to 5,000,000 is 30%, and over 5,000,000 is 35%. If you have non-salary income and a minimum tax of 0.5% of that income is higher than the progressive tax, the table uses the minimum tax instead and says so.

Before the tax year ends, the tool is in planning mode, with Insurance and Savings and investment sections where you can try amounts you plan to buy. From 1 January of the following year it switches to filing mode: it asks for the tax withheld from your salary for the full year, then tells you whether you owe more or get a refund. Before a salary is entered, the tax bracket and the RMF + ThaiESG figures show as N/A in grey.

How to use it

1. Open the tax calculator and enter the monthly salary, or enter it in the customer details bar at the top
2. In the Income section, add bonuses, severance pay and withholding tax. For other income types, press "Add or remove income items"
3. Open the Deductions section, check marital status and children, then enter the deductions you have
4. In the Insurance and Savings and investment sections, try amounts of RMF, ThaiESG or insurance you plan to buy and watch the tax in the headline change
5. Open the tax rate table to see where each figure comes from, step by step
6. Press "Add to summary" to keep the result in the meeting summary of the financial planning page, or "Reset" to start the tax topic again