# Reverse Sales Tax Calculator

> Calculate the pre-tax price and tax amount when the total price including sales tax is known.

Page: https://askcalculators.com/calculator/reverse-sales-tax-calculator/
Definition: https://askcalculators.com/calculator/reverse-sales-tax-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/reverse-sales-tax-calculator/schema.json
Version: 1.0.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/calculator/reverse-sales-tax-calculator/?totalWithTax=106.25&salesTaxRate=6.25

## Inputs
- totalWithTax: Total price including tax; type=money; required; default=106.25; min=0
- salesTaxRate: Sales tax rate; type=percent; required; default=6.25; min=0; max=1000

## Outputs
- preTaxPrice: Price before tax; format=currency; primary
- salesTaxAmount: Sales tax amount; format=currency
- taxShareOfTotal: Tax as % of total; format=percent
- verificationTotal: Recomputed total; format=currency

## Formula
pre-tax price = total ÷ (1 + tax rate); tax = total − pre-tax price

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.