Personal Tax: Online Filing Guide (E-Filing)

Filing personal income tax online is faster and easier than paper filing. Here's your complete step-by-step guide.

 

Before You Start

Create RD Smart Tax Account

First-time users:

1. Go to: https://rdsmartax.rd.go.th
2. Click "Register"
3. Provide: Tax ID, name, email, phone
4. Verify email
5. Set password

 

Gather Documents

• Form 50 (from employer showing salary and withheld tax)
• Insurance premium receipts
• Investment fund statements
• Donation receipts
• Other deduction documents

 

Step-by-Step E-Filing Process

Step 1: Log In

1. Go to RD Smart Tax portal
2. Enter Tax ID and password
3. Complete 2-factor authentication (SMS code)

 

Step 2: Select Tax Form

1. Click "Personal Income Tax"
2. Select "Por Ngor Dor 90" (for employees) or "Por Ngor Dor 91" (for business owners)
3. Choose tax year: 2025

 

Step 3: Import Employer Data

If your employer filed electronically:

1. Click "Import Data"
2. System auto-fills salary and withheld tax
3. Verify accuracy

If not available:

1. Manually enter from Form 50
2. Salary amount
3. Tax withheld

 

Step 4: Enter Other Income

Add any additional income:

• Business income
• Rental income
• Investment income
• Interest (if > 20,000 THB)
• Dividends

 

Step 5: Claim Deductions

Personal Allowances:

• Personal: 60,000 THB (auto-filled)
• Spouse: 60,000 THB (if applicable)
• Children: 30,000 THB each
• Parents: 30,000 THB each (if eligible)

 

Insurance:

• Life insurance premiums (max 100,000 THB)
• Health insurance (max 25,000 THB)
• Upload: Premium receipts (PDF)

 

Retirement Savings:

• Provident fund contributions
• RMF purchases
• LTF purchases
• Upload: Fund statements

 

Other Deductions:

• Home loan interest (max 100,000 THB)
• Donations (max 10% of net income)
• Upload: Supporting documents

 

Step 6: Review Calculation

System automatically calculates:

1. Gross income: All income sources
2. Less deductions: All allowances and deductions
3. Taxable income: What you pay tax on
4. Tax liability: Based on progressive rates
5. Less tax paid: Withheld by employer
6. Result: Refund or additional tax owed

 

Step 7: Upload Supporting Documents

Required uploads (PDF):

• Form 50 from employer
• Insurance receipts
• Fund statements
• Donation receipts
• Other deduction proof

File size limit: 5 MB per document Format: PDF only

 

Step 8: Review and Confirm

1. Review all entered information
2. Check calculations
3. Verify uploaded documents
4. Read declaration
5. Check "I confirm" box

 

Step 9: Submit

1. Click "Submit"
2. System validates data
3. If errors: Fix and resubmit
4. If successful: Receive confirmation number

 

Step 10: Download Confirmation

1. Download filed return (PDF)
2. Save confirmation number
3. Print for records (optional)

 

Step 11: Payment (if tax owed)

If you owe additional tax:

1. Click "Make Payment"
2. Choose payment method:
   • Online banking
   • Credit card
   • Counter service
3. Complete payment
4. Save receipt

Deadline: May 31 (same as filing)

 

Step 12: Refund (if overpaid)

If you're owed a refund:

1. System automatically processes
2. Refund timeline: 60-90 days
3. Direct deposit to registered bank account
4. Track status in portal

 

Common E-Filing Issues

Issue 1: Can't Import Employer Data

Solution: Enter manually from Form 50

 

Issue 2: Upload Fails

Solution:

• Check file size (< 5 MB)
• Ensure PDF format
• Try different browser

 

Issue 3: Calculation Seems Wrong

Solution:

• Double-check all entries
• Verify deduction limits
• Contact RD hotline: 1161

 

Issue 4: Can't Submit

Solution:

• Check for error messages
• Ensure all required fields filled
• Verify uploaded documents

 

E-Filing vs. Paper Filing

| Feature | E-Filing | Paper | |---------|----------|-------| | Deadline | May 31 | March 31 | | Location | Anywhere | Revenue Dept office | | Confirmation | Immediate | Wait in line | | Refund | 60-90 days | 90-120 days | | Amendments | Easy online | Must visit office |

 

Tips for Success

File Early

• Don't wait until May 31
• File in March-April for faster refund
• Avoid last-minute technical issues

 

Save Everything

• Download filed return
• Save confirmation number
• Keep payment receipts
• Store for 5 years

 

Double-Check Deductions

• Maximize all eligible deductions
• Don't leave money on the table
• Review limits carefully

 

Use Help Resources

• RD Smart Tax has tutorials
• Call 1161 for support
• Or hire accountant (3,000-5,000 THB)

 

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Related Service: Accounting & Tax Compliance — Personal tax e-filing assistance.