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Sales Tax Calculator

Calculate sales tax in two modes: add tax to a pre-tax amount, or extract tax from a post-tax (tax-inclusive) amount. Useful for VAT and GST calculations.

Calculation Mode

Amount

₫

Tax Rate

Fill in the fields above and click Calculate to see your results.

How to use

Calculate sales tax in two modes: add tax to a pre-tax amount, or extract tax from a post-tax (tax-inclusive) amount. Useful for VAT and GST calculations.

How it's calculated

Tax Amount (pre-tax mode)

amount * tax_rate / 100

Tax to add on top of the pre-tax amount

Total with Tax

amount + tax_amount_pretax

Pre-tax amount plus tax

Tax Amount (post-tax mode)

amount - amount / (1 + tax_rate / 100)

Tax extracted from the tax-inclusive amount

Pre-tax Amount

amount / (1 + tax_rate / 100)

Original price before tax was added

Tax Amount

(mode == 1) * tax_amount_pretax + (mode == 2) * tax_amount_posttax

Tax amount for the selected mode

Final Amount

(mode == 1) * total_with_tax + (mode == 2) * pretax_amount

Total with tax (pre-tax mode) or pre-tax amount (post-tax mode)

Examples

Pre-tax: 1,000,000 ₫ at 10% → total 1,100,000 ₫

Calculation Mode:1
Amount:1,000,000
Tax Rate:10

Post-tax: 1,100,000 ₫ at 10% → tax = 100,000 ₫

Calculation Mode:2
Amount:1,100,000
Tax Rate:10

Frequently Asked Questions

What is the difference between pre-tax and post-tax mode?

Pre-tax mode (mode 1): you enter the price before tax and the calculator adds the tax on top. Post-tax mode (mode 2): you enter the final price that already includes tax and the calculator extracts how much of it is tax.

How do I extract tax from a tax-inclusive price?

Select mode 2 (Post-tax), enter the total price and tax rate. The pre-tax amount = Total ÷ (1 + Tax Rate ÷ 100). For a 1,100,000 ₫ total at 10% tax: 1,100,000 ÷ 1.1 = 1,000,000 ₫ pre-tax, so tax = 100,000 ₫.

What tax rate should I use in Vietnam?

Vietnam's standard VAT rate is 10%. A reduced rate of 5% applies to essential goods like food and medicine. Some goods are VAT-exempt (0%). Check the current regulations for your specific product or service.