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Thai late-tax surcharge calculator

Calculate the 1.5% monthly-or-part surcharge from a user-confirmed period count.

Limited scopePreliminary referenceRevenue Code section 27 · Confirm period count
Saves this tool's name on this device only (up to 20). No form values.
Only visible result text is included. Form fields are not read. Review sensitive values before sharing.

You must confirm the due date and count each month or part with the Revenue Department. This excludes penalties, criminal fines, extensions and special rules.

Enter values, then process to see the result.

How to use it

  1. Confirm that the stated scope applies.
  2. Enter the checked base and select the applicable option.
  3. Review the breakdown, source and exclusions.

Important limitation

Calculates only section 27 surcharge from a user-confirmed month-or-part count; excludes penalties, criminal fines, exceptions and extensions.

The interactive form is fully localized in English.

Reviewed 2026-09-16; next review 2026-12-16.

Available for trial use while references or examples are being expanded.

Sources

ประมวลรัษฎากร มาตรา 27กรมสรรพากร · opens in a new tabThe 1.5% rate per month or part, counting basis and cap at the outstanding tax.Source checked 2026-09-16
Recorded updates

Review history

Site changelog

Dates describe the review scope recorded below. A page update does not mean every source was checked again.

  1. Last recorded source/method review

    Available for trial use while references or examples are being expanded.

Related guides

How to count Thai tax surcharge under Revenue Code Section 27Understand the meaning, scope and sources before using the result.

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