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Finance Calc Kit
Tax

Sales Tax Calculator

Calculate sales tax rate, before-tax price, after-tax price, and tax amount instantly.

Sales tax inputs

$
%

After-tax price

$106.50

$100.00 before tax + $6.50 tax

Before-tax price

$100.00

Sales tax rate

6.50%

Sales tax amount

$6.50

Report tool

Calculate sales tax in three directions

Sales tax is usually added as a percentage of the pre-tax price. Depending on what you know, you may need the after-tax total, the pre-tax base, or the implied tax rate from two receipt amounts. This calculator supports all three with one mode selector.

When you need separate state, use, and local tax lines on one receipt, use the state and local sales tax calculator. State and local rates vary widely. For combined rates in specific states, try the Missouri sales tax calculator or the Ohio sales tax calculator. Retailers pricing with tax included can use the margin and sales tax calculator.

Key formulas

Tax Amount=Before-Tax Price×Rate100\text{Tax Amount} = \text{Before-Tax Price} \times \frac{\text{Rate}}{100}
After-Tax Price=Before-Tax Price×(1+Rate100)\text{After-Tax Price} = \text{Before-Tax Price} \times \left(1 + \frac{\text{Rate}}{100}\right)
Rate %=After-Tax Price−Before-Tax PriceBefore-Tax Price×100\text{Rate \%} = \frac{\text{After-Tax Price} - \text{Before-Tax Price}}{\text{Before-Tax Price}} \times 100

Worked example

A $100 item with 6.5% sales tax adds $6.50 in tax for an after-tax price of $106.50. Working backward from $106.50 at 6.5% gives a before-tax price of $100.00. If you only know $100 pre-tax and $106.50 total, the implied rate is 6.5%.

Frequently asked questions

Is sales tax calculated on the pre-tax price?
In most U.S. sales tax systems, yes. Tax is applied to the taxable base before tax, then added to reach the total due.
How do I find the pre-tax price from a receipt total?
Switch to before-tax mode, enter the after-tax total and known rate. The calculator divides by (1 + rate/100) to reverse the tax.
Can after-tax price be lower than before-tax price?
No for standard sales tax. After-tax price equals or exceeds the pre-tax base. The rate mode rejects totals below the pre-tax amount.
Does this cover use tax or VAT?
The math is the same for any percentage added to a base price, but VAT and use tax have different compliance rules. Confirm your jurisdiction before filing.

Resources and references

The formulas and methods in this calculator were checked against these independent sources.