Business calculator
Editor
Enter the amount, tax rate, quantity, and any simple adjustments in one clear layout. The subtotal, tax amount, and final total update instantly as you compare add-tax and reverse-tax scenarios.
This calculator keeps the core sales tax fields visible by default and uses the tax rate you enter. It does not look up jurisdiction-specific rates or tax rules.
Calculation mode
Choose whether you want to add sales tax to a pre-tax amount or remove sales tax from a tax-included total.
Price and tax inputs
Start with the amount and the sales tax rate, then use quantity to scale the estimate from one item to a larger purchase.
This is a practical percentage-based sales tax calculator, not a jurisdiction lookup tool. Actual tax treatment can vary by location, product type, shipping rules, and exemptions.
Optional adjustments
Use discount and shipping inputs when they help match a real checkout or order estimate. In this version, discount is applied before tax and shipping is treated as taxable.
The order of operations is subtotal, discount, shipping, tax, then final total. In reverse-tax mode, the same assumptions are used to split a tax-included total back into pre-tax pieces.
Results
Final total
$108.25
Pre-tax subtotal
$100.00
Sales tax amount
$8.25
Sales tax rate
8.25%
Final total
$108.25
Subtotal before discount
$100.00
Discount amount
$0.00
Shipping / handling
$0.00
Taxable amount
$100.00
Subtotal before discount
$100.00
Sales tax
$8.25
Final total
$108.25
| Metric | Value |
|---|---|
| Unit price before tax | $100.00 |
| Quantity | 1 |
| Subtotal before discount | $100.00 |
| Discount | $0.00 |
| Pre-tax subtotal | $100.00 |
| Shipping / handling | $0.00 |
| Taxable amount | $100.00 |
| Sales tax rate | 8.25% |
| Sales tax amount | $8.25 |
| Final total | $108.25 |
How it works
A sales tax calculator helps you estimate the tax amount on a purchase and the final total after tax is added. It can also work in reverse by taking a tax-included total and estimating the pre-tax subtotal plus the tax portion.
In add-tax mode, the calculator starts with the pre-tax subtotal, subtracts any discount, adds shipping, and then multiplies the taxable amount by the sales tax rate you entered. The tax amount is then added to reach the final total.
In reverse-tax mode, the calculator divides the tax-included total by one plus the tax rate to estimate the pre-tax amount. The difference between the entered total and the derived pre-tax amount is the estimated sales tax portion.
The sales tax rate is the percentage applied to the taxable amount. This calculator does not look up rates automatically, so the quality of the estimate depends on the tax rate you enter for your scenario.
Quantity scales the subtotal across multiple items. Discount reduces the subtotal before tax is applied. In this first version, shipping and handling are treated as taxable so they flow into the taxable amount before the final tax is calculated.
Results are based only on the values you enter. Actual sales tax obligations can vary by jurisdiction, product taxability, shipping treatment, exemptions, and other rules. Use this page for planning and quick calculations, not for compliance guarantees.