Thai VAT Explained: The Two Directions People Mix Up

ภาษีมูลค่าเพิ่ม 7% คิดยังไง แบบไม่สับสน

2026-09-18 · 5 min read

Two directions, two formulas

Given a net price, VAT is easy: multiply by 1.07. Going the other way — a shelf price that already includes tax — you divide by 1.07. That division is the step people skip, and it is why so many quotes are a few percent light.

ทิศทางหนึ่งคูณ 1.07 อีกทิศทางหาร 1.07 — สองสิ่งนี้ไม่ใช่เรื่องเดียวกัน

A worked example

A service quoted at 10,000 baht net becomes 10,700 baht gross. Now reverse it: a 10,700 baht shelf price is not 700 baht of tax on a 10,000 baht base — dividing 10,700 by 1.07 gives exactly 10,000, and the tax is 700. So far so good. But a 15,000 baht shelf price gives 14,018.69 net and 981.31 tax — not 1,050.

When to quote inclusive and when not

• Selling to consumers: quote VAT-inclusive. Nobody wants to do arithmetic at checkout.
• Selling to businesses: quote net plus tax as a separate line, because they reclaim it.
• Publishing a price publicly: be explicit either way — "prices shown include VAT" prevents disputes.

Rounding

Round the final figure, not the intermediate one. Rounding each line item drifts the total by a baht or two, which is small until an auditor asks why the invoice does not balance.

Related tools

• The VAT calculator does both directions and shows net, tax and total at once.
• Pair it with the invoice template for quotes that match what you actually charge.