Sales Tax Calculator

Sales Tax is evaluated from Price, Sales Tax Rate and Calculation Mode. The calculation reports Pre-Tax Price, Tax Amount and Total Price.

Results

Thanks — we’ve logged this for review.

About the Sales Tax Calculator

Sales Tax is treated here as a quantitative relation between Price, Sales Tax Rate and Calculation Mode and Pre-Tax Price, Tax Amount and Total Price.

The calculator uses a multi formula configuration. Each reported value is read as a direct evaluation of the stored rules with the declared field formats and units.

Formula basis:
**Add tax mode:**
Tax Amount = Price x Rate
Total = Price x (1 + Rate)
**Reverse (tax included) mode:**
Pre-Tax Price = Total / (1 + Rate)
Tax Amount = Total - Pre-Tax Price

Interpret the outputs in the order shown by the result fields. Optional inputs affect only the outputs that depend on those variables.

Formula & How It Works

The calculation applies the following relations exactly as recorded in the metadata:

**Add tax mode:**
Tax Amount = Price x Rate
Total = Price x (1 + Rate)
**Reverse (tax included) mode:**
Pre-Tax Price = Total / (1 + Rate)
Tax Amount = Total - Pre-Tax Price

Each output field is produced by substituting the supplied inputs into the relevant relation and then applying the declared rounding or text format.

Worked Examples

Example 1: Standard Purchase — Add Tax

Inputs

amount: 149.99 tax_rate: 8.75 mode: add
Pre-Tax Price: $149.99. Tax Amount: $13.12. Total Price: $163.11

With Price = 149.99, Sales Tax Rate = 8.75 and Calculation Mode = add as the stated inputs, the result is Pre-Tax Price = $149.99, Tax Amount = $13.12 and Total Price = $163.11. Each value corresponds to the declared output fields.

Example 2: Reverse Calculation — Receipt Audit

Inputs

amount: 250 tax_rate: 9.25 mode: reverse
Pre-Tax Price: $228.83. Tax Amount: $21.17. Total Price: $250

With Price = 250, Sales Tax Rate = 9.25 and Calculation Mode = reverse as the stated inputs, the result is Pre-Tax Price = $228.83, Tax Amount = $21.17 and Total Price = $250. Each value corresponds to the declared output fields.

Example 3: No Sales Tax State

Inputs

amount: 500 tax_rate: 0 mode: add
Pre-Tax Price: $500. Tax Amount: $0. Total Price: $500

With Price = 500, Sales Tax Rate = 0 and Calculation Mode = add as the stated inputs, the result is Pre-Tax Price = $500, Tax Amount = $0 and Total Price = $500. Each value corresponds to the declared output fields.

Example 4: Small Business — Computing Taxes on Sales

Inputs

amount: 1200 tax_rate: 10.25 mode: add
Pre-Tax Price: $1,200. Tax Amount: $123. Total Price: $1,323

With Price = 1,200, Sales Tax Rate = 10.25 and Calculation Mode = add as the stated inputs, the result is Pre-Tax Price = $1,200, Tax Amount = $123 and Total Price = $1,323. Each value corresponds to the declared output fields.

Common Use Cases

  • Calculate the total price of a purchase including sales tax
  • Back-calculate the pre-tax price from a total amount paid
  • Compare sales tax burden across different states