Sales Tax Calculator
Calculate sales tax amount and final total price with decimal arithmetic and pre-tax reverse calculation.
Sales tax
Sales tax formulas
Direct formulas to calculate tax added and reverse pre-tax amounts:
Tax amount
Tax added to subtotal
Total with tax
Final checkout price
Pre-tax price
Reverse calculation
Frequently asked questions
How do you calculate sales tax?
Multiply the pre-tax price by the sales tax rate and divide by 100: Tax = Price × (Rate ÷ 100). Add the tax to the price to get the total: Total = Price + Tax = Price × (1 + Rate ÷ 100).
How do you calculate the price before sales tax?
Divide the tax-inclusive total by (1 + Tax Rate ÷ 100). For example, if a total is $108.25 with an 8.25% sales tax rate: $108.25 ÷ 1.0825 = $100.00 pre-tax price.
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