How to Calculate Sales Tax: Add It to a Price or Find It in a Total
Learn how to add sales tax to a price, remove tax from a total, and find the pre-tax amount using simple formulas and examples.
Quick navigation
Table of contents
Adding sales tax to a price
When you know the pre-tax price and the tax rate:
- Tax = price × tax rate / 100
- Total = price + tax, or price × (1 + rate / 100)
Example: $50 with 8% tax
Tax is 50 × 8 / 100 = $4, so the total is $54.
Finding the tax inside a total
If the total already includes tax, divide the total by (1 + rate / 100) to get the pre-tax price. For a $54 total at 8%, 54 / 1.08 = $50, so the tax included is $4.
A common mistake is subtracting 8% of $54, which gives $49.68 and is slightly wrong.
Things that can change the result
Always confirm the rate that applies to your purchase. The same method works for VAT and GST.
- Tax rates differ by country, state, and product type.
- Some items are exempt or taxed at a reduced rate.
- Rounding rules may differ between stores and invoices.
FAQ
How do I remove sales tax from a total?
Divide the total by 1 plus the tax rate as a decimal. For example, divide by 1.08 for an 8% tax.
Does the formula work for VAT and GST?
Yes. VAT and GST are percentage taxes, so the same add-on and reverse calculations apply.
Why is my receipt a few cents different?
Stores may round tax per item or on the whole bill, which can change the final amount slightly.
