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VAT registration threshold checker (THB 1.8m)

Quick answer

Once taxable sales of goods or services pass THB 1.8m within the year, registration must be applied for within thirty days of crossing. The test uses cumulative revenue for the year, not one month, and after registration PP.30 is due every month even with no transactions. The calculator is free, needs no sign-up and runs entirely in your browser.

Steps at a glance

  1. Add up the revenue that counts
  2. Find the month you cross
  3. Prepare form PhorPhor.01
  4. Check the result against your source documents before filing.

What to prepare

  • The base amount from a tax invoice, bill or payslip.
  • The rate or income category that applies to the item.
  • Whether the entity is VAT-registered.
  • The tax period or month you are calculating.

Need a scope assessment? Describe the accounting or tax issue, relevant periods and due dates so the checks, required records and responsibilities can be clarified before a meeting.

Discuss your scope
Cumulative taxable revenue
100,000 THB
Registration threshold
1,800,000 THB
Share of the threshold used
5.6%
Headroom left
1,700,000 THB
Status
Projected to cross in about 12 months
Projected revenue over the next twelve months
1,900,000 THB

Figures are planning estimates, not tax advice. Have an accountant or CPA review your supporting documents before filing.

Hands comparing receipts beside a calculator and laptop; not Thai tax invoices
Content illustration; not company staff or a client engagement.Kaboompics · Pexels License

Formula used

Headroom = 1,800,000 − cumulative revenue · Months to threshold = headroom ÷ average monthly sales

How to use it and file correctly

  1. 1

    Add up the revenue that counts

    Only revenue within the VAT scope counts; income the law exempts is left out of the threshold test.

  2. 2

    Find the month you cross

    Project forward with the average monthly figure so you know in advance which month passes THB 1.8m and can prepare the paperwork early.

  3. 3

    Prepare form PhorPhor.01

    You need proof of the business premises, a lease or consent letter, a map, photos of the location and the current corporate documents.

  4. 4

    Switch the paperwork over at once

    Obligations start on the effective registration date — issuing tax invoices and keeping input/output tax reports — not on the day the certificate arrives.

Common pitfalls

  • Passing the threshold without registering still leaves you liable for the output tax you should have charged, even though the customer has gone.

  • Voluntary registration brings immediate monthly filing duties; weigh that against the input-tax benefit before deciding.

  • Splitting sales across entities to stay under the threshold is a recognised audit trigger and can be assessed retrospectively.

Frequently asked questions

Calendar year or accounting period?

Companies use their accounting period and individuals use the tax year; either way the test looks at the cumulative amount actually earned in that cycle.

Do overseas online sales count?

Exported goods sit inside the VAT system at a zero rate, so they still count toward the test even though no output tax is charged.

When does the 30 days start?

From the first day cumulative taxable value exceeds THB 1.8m, not from month-end or the period close.

Can registration be cancelled later?

Deregistration is possible on qualifying grounds such as sustained revenue below the threshold or ceasing business, but outstanding returns and reclaimed input tax must be settled first.

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